阅读说明：本技术 激光模块 (Laser module ) 是由 内山正裕 于 2018-11-28 设计创作，主要内容包括：本发明在激光模块中使各激光二极管生成的激光与在光纤内传输的激光的耦合效率提高。激光模块(1)具备光纤、n个激光二极管LD<Sub>i</Sub>以及n个准直透镜SL<Sub>i</Sub>。在激光模块(1)中,与激光二极管LD<Sub>1</Sub>对应的准直长度LC<Sub>1</Sub>与相对于各准直透镜SL<Sub>i</Sub>设定好的特定的距离SL不等。(The invention improves the coupling efficiency of the laser generated by each laser diode and the laser transmitted in the optical fiber in the laser module. A laser module (1) is provided with an optical fiber and n Laser Diodes (LD) i And n collimator lenses SL i . In the laser module (1), the laser diode LD 1 Corresponding collimation length LC 1 And with respect to each collimator lens SL i The set specific distance SL varies.)

1. A laser module comprises an optical fiber, and an optical path length LO corresponding to the optical path length from the optical fiber_iN laser diodes LD with sequence from long to short of i ═ 1, 2, ·, n_iAnd n collimator lenses SL respectively disposed in the middle of the optical paths_iThe method is characterized in that the method comprises the following steps of,

from each laserDiode LD_iTo each collimating lens SL_iAs the collimation length LC_iAnd a laser diode LD₁Corresponding collimation length LC₁And laser diode LD_nCorresponding collimation length LC_nAt least one of the collimating lenses SL_iThe determined specific distance SL is not equal.

2. A laser module as defined in claim 1,

the specific distance SL is set so that the laser diodes LD are driven from each other_iOutput and pass through each collimating lens SL_iThe optical path of each laser is parallel or divergent,

at least a collimating lens SL₁Configured to satisfy SL < LC₁。

3. A laser module as claimed in claim 2,

and laser diode LD₁And laser diode LD_nAll different laser diodes as laser diodes LD_mAnd each laser diode LD_jCorresponding collimating lenses SL_jConfigured to satisfy SL < LC_m≤LC_j＜LC₁Wherein j is more than or equal to 2 and less than or equal to m.

4. A laser module as defined in claim 1,

the specific distance SL is set so that the laser diodes LD are driven from each other_iOutput and pass through each collimating lens SL_iThe optical path of each laser is parallel or divergent,

at least a collimating lens SL_nConfigured to satisfy LC_n＜SL。

5. A laser module as defined in claim 1,

the specific distance SL is set so that the laser diodes LD are driven from each other_iOutput and pass through each collimating lens SL_iThe light path of each laser beam is converged,

at least a collimating lens SL_nConfigured to satisfy SL < LC_n。

6. A laser module as defined in claim 5,

and laser diode LD₁And laser diode LD_nAll different laser diodes as laser diodes LD_mAnd each laser diode LD_jCorresponding collimating lenses SL_jConfigured to satisfy SL < LC_m≤LC_j＜LC_nWherein j is m is not less than j is not more than n-1.

7. A laser module as defined in claim 1,

the specific distance SL is set so that the laser diodes LD are driven from each other_iOutput and pass through each collimating lens SL_iThe light path of each laser beam is converged,

at least a collimating lens SL₁Configured to satisfy LC₁＜SL。

8. Laser module according to one of claims 1 to 7,

further, the optical path control device further includes collimator lenses SL respectively disposed in the middle of the optical paths and positioned at the respective positions_iN mirrors M between said optical fibers_i，

Each reflector M_iThe optical paths are arranged to be bent at predetermined angles.

9. A laser module as defined in claim 8,

further comprises a substrate having a mounting surface S on which the laser diodes LD are mounted_iAnd each collimating lens SL_iAnd each reflector M_i，

The mounting surface S includes at least n sub-mounting surfaces SS each having a height gradually decreased as approaching the optical fiber_i，

On each sub-carrier plane SS_iCarries a corresponding laser diode LD_iCollimator lens SL_iAnd a mirror M_i。

10. A laser module comprises an optical fiber, and an optical path length LO corresponding to the optical path length from the optical fiber_iN laser diodes LD with sequence from long to short of i ═ 1, 2, ·, n_iAnd n collimator lenses SL respectively disposed in the middle of the optical paths_iThe method is characterized in that the method comprises the following steps of,

each collimating lens SL_iAs the curvature r_iAnd a laser diode LD₁Corresponding collimating lens SL₁Curvature r of₁And laser diode LD_nCorresponding collimating lens SL_nCurvature r of_nAt least one of the collimating lenses has a different curvature from the other collimating lenses.

11. A laser module as defined in claim 10,

at least a curvature r₁Less than the curvature of the other collimating lens.

12. A laser module comprises an optical fiber, and an optical path length LO corresponding to the optical path length from the optical fiber_iN laser diodes LD with sequence from long to short of i ═ 1, 2, ·, n_iAnd n collimator lenses SL respectively disposed in the middle of the optical paths_iThe method is characterized in that the method comprises the following steps of,

each laser diode LD_iThe emitter size ES is the size of the emitter_iEmitter size ES₁And emitter size ES_nAt least one of the laser diodes has an emitter size different from that of the other laser diodes.

13. A laser module as defined in claim 12,

at least the emitter size ES₁Smaller than the emitter size of said other laser diode.

Technical Field

The present invention relates to a laser module including a plurality of laser diodes and an optical fiber.

Background

As an excitation light source of a fiber laser, a laser module including a plurality of laser diodes and an optical fiber is widely used. In such a laser module, laser light output from a plurality of laser diodes is input to an optical fiber. By using such a laser module, it is possible to obtain laser light of large power that cannot be obtained from a single laser diode. A laser module 101 shown in fig. 7 (see patent document 1) is a typical conventional laser module.

In the laser module 101 shown in fig. 7, the laser light output from the 7 laser diodes LD1 to LD7 is guided to the optical fiber OF by using the 7 mirrors M1 to M7. That is, the laser beams output from the laser diodes LD1 to LD7 and the laser beam propagating through the optical fiber OF are optically coupled via these optical components. The laser light propagating through the optical fiber OF is output from the laser module 101. In fig. 7, only principal rays of laser light output from the laser diodes LD1 to LD7 are shown by broken lines.

According to the laser module 101 configured as described above, output laser light having a power about 7 times as large as the laser light output from each laser diode can be obtained.

Patent document 1: japanese patent laid-open publication No. 2013-235943 (published 2013 in 11 months and 21 days)

In the conventional laser module 101, the power OF the output laser beam depends on the coupling efficiency OF the coupling between the laser beams output from the laser diodes LD1 to LD7 and the laser beam propagating through the optical fiber OF. The higher the coupling efficiency, the higher the power of the output laser of the laser module 101. That is, the power of the laser beams output from the laser diodes LD1 to LD7 can be converted into the power of the output laser beams with higher efficiency. However, when this coupling efficiency is focused on, there is still room for improving the coupling efficiency in the conventional laser module 101.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object of the present invention is to improve coupling efficiency between laser light generated by each laser diode and laser light propagating through an optical fiber in a laser module including a plurality of laser diodes and the optical fiber.

In order to solve the above-described problem, a laser module according to one aspect of the present invention includes an optical fiber, and an optical path LO that is a length of an optical path to the optical fiber_iN laser diodes LD with sequence from long to short of i ═ 1, 2, ·, n_iAnd n collimator lenses SL respectively disposed in the middle of the optical paths_i. In the laser module, each laser diode LD_iTo each collimating lens SL_iAs the collimation length LC_iAnd a laser diode LD₁Corresponding collimation length LC₁And laser diode LD_nCorresponding collimation length LC_nAt least one of the collimating lenses SL_iThe determined specific distance SL is not equal.

In order to solve the above-described problem, a laser module according to one aspect of the present invention includes an optical fiber, and an optical path LO that is a length of an optical path to the optical fiber_iN laser diodes LD with sequence from long to short of i ═ 1, 2, ·, n_iAnd n collimator lenses SL respectively disposed in the middle of the optical paths_i. In the laser module, each collimator lens SL_iAs the curvature r_iAnd a laser diode LD₁Corresponding collimating lens SL₁Curvature r of₁And laser diode LD_nCorresponding collimating lens SL_nCurvature r of_nAt least one of the collimating lenses has a different curvature from the other collimating lenses.

In order to solve the above-described problem, a laser module according to one aspect of the present invention includes an optical fiber, and an optical path LO that is a length of an optical path to the optical fiber_iN laser diodes LD with sequence from long to short of i ═ 1, 2, ·, n_iAnd n collimator lenses SL respectively disposed in the middle of the optical paths_i. In the laser module, each laser diode LD_iThe emitter size ES is the size of the emitter_iEmitter size ES₁And emitter size ES_nAt least one of the laser diodes has an emitter size different from that of the other laser diodes.

A laser module according to an aspect of the present invention is a laser module including a plurality of laser diodes and an optical fiber, and can improve the coupling efficiency between laser light generated by each laser diode and laser light propagating through the optical fiber.

Drawings

Fig. 1 is a perspective view of a laser module as embodiment 1 of the present invention.

Fig. 2 is a three-view illustration of the laser module shown in fig. 1.

Fig. 3 (a) is a schematic diagram in the case of a unit optical system in which n is 4 among the unit optical systems included in the laser module shown in the plan view 1. Fig. 3 (b) is a schematic diagram showing a unit optical system in which n is 1 among the unit optical systems included in the laser module of the comparative example shown in the plan view 7. Fig. 3 (c) is a schematic diagram of the unit optical system in which n is 1 among the unit optical systems included in the laser module shown in the plan view 1.

Fig. 4 (a) is a distribution diagram of illuminance of each laser beam on the incident surface of the condensing lens commonly provided in the laser module shown in fig. 1 and the laser module of the comparative example shown in fig. 7. Fig. 4 (b) is an angular distribution diagram of each laser beam on the incident surface of the optical fiber included in the laser module of the comparative example shown in fig. 7. Fig. 4 (c) is an angular distribution diagram of each laser beam on the incident surface of the optical fiber included in the laser module shown in fig. 1.

Fig. 5 (a) is a graph showing a correlation between a coupling efficiency and a collimation length in a unit optical system provided in a laser module according to embodiment 1 of the present invention. Fig. 5 (b) is a graph showing a preferred collimation length for each unit optical system provided in the laser module according to embodiment 1 of the present invention.

Fig. 6 (a) is a graph showing the correlation between the coupling efficiency and the curvature of the S-axis collimator lens in the unit optical system provided in the laser module according to embodiment 2 of the present invention. Fig. 6 (b) is a graph showing a curvature suitable for each unit optical system provided in the laser module according to embodiment 2 of the present invention.

Fig. 7 is a perspective view of a conventional laser module.

Detailed Description

[ 1 st embodiment ]

(Structure of laser Module)

A structure of a laser module 1 according to embodiment 1 of the present invention will be described with reference to fig. 1. Fig. 1 is a perspective view of a laser module 1.

As shown in FIG. 1, the laser module 1 has 7 laser diodes LD₁～LD₇7F-axis collimating lenses FL₁～FL₇7S-axis collimating lenses SL₁～SL₇7 reflectors M₁～M₇One condenser lens FL and one optical fiber OF. Laser diode LD₁～LD₇F-axis collimating lens FL₁～FL₇S-axis collimating lens SL₁～SL₇Mirror M₁～M₇And a condensing lens FL is mounted on a bottom plate B of the housing of the laser module 1. The optical fiber OF penetrates the side wall OF the housing OF the laser module 1 to include an incident end face OF_IThe inner end is introduced into the housing of the laser module 1. In fig. 1, a side wall of the housing of the laser module 1 is not shown.

The substrate B as claimed in the claims is composed of a pair of main surfaces facing each other and 4 side surfaces. Hereinafter, a principal surface of the pair of mutually opposing principal surfaces of the base plate B, which principal surface is on the positive z-axis direction side in the coordinate system shown in fig. 1, will be referred to as a placement surface S. The carrier surface S at least comprises 7 sub-carrier surfaces SS_i. Each sub-carrying surface SS_iIs a plane (parallel plane in the present embodiment) along the xy plane in the illustrated coordinate system, and is configured so as to approach the incident end face OF the optical fiber OF_IWhile its height becomes lower stepwise. In other words, the base plate B is configured to: OF at the exit end face_ISub-carrier plane SS of farthest position₁Is highest as approaching the incident end face OF_ISub-carrier surface SS_iIs gradually reduced and is located at the incident end face OF_ISub-carrier plane SS of the nearest position₇Is the lowest.

On the sub-carrier plane SS_iRespectively mounted with a laser diode LD_i. Each laser diode LD_iAccording to the incident end face OF from the emission end face to the optical fiber OF_IOptical path length, that is, optical path length LO_iThe sequence from long to short is i ═ 1, 2, ·, 6 and 7. That is, the laser diode LD₁Mounted on the off-incident end face OF_IThe furthest position, and thus the optical path LO₁Longest, laser diode LD₇Carried on the incident end face OF_ITo the nearest position of the optical path LO₇And shortest.

On the sub-carrier plane SS_iExcept for the laser diode LD_iIn addition, a laser diode LD is mounted_iCorresponding S-axis collimating lens SL_iF-axis collimating lens FL_iAnd a reflector M_i. I.e. on the sub-mount surface SS_iLaser diode LD mounted therein_iS-axis collimating lens SL_iF-axis collimating lens FL_iAnd a reflector M_i. Is arranged on a sub-carrier surface SS_iLaser diode LD_iS-axis collimating lens SL_iF-axis collimating lens FL_iAnd a mirror M_iThe condenser lens FL and the optical fiber OF constitute a unit optical system for coupling the laser beam LBi and the laser beam propagating through the optical fiber OF.

Laser diode LD_i(i is a natural number of 1. ltoreq. i.ltoreq.7) is an output laser LB₁～LB₇The light source of (1). In the present embodiment, in the illustrated coordinate system, a laser diode in which the active layer is arranged parallel to the xy plane and the emission end face is arranged parallel to the zx plane is used as the laser diode LD_iThe preparation is used. For laser diode LD_iIn other words, the laser beam LB having the forward direction of the y-axis, the F-axis (fast axis) parallel to the z-axis, and the S-axis (slow axis) parallel to the x-axis is output_i. These laser diodes LD_iAs described above, the sub-mounting surfaces SS are respectively mounted on the sub-mounting surfaces SS having different heights_i. In addition, these laser diodes LD₁～LD₇Configured as laser diodes LD_iLies on a plane parallel to the particular zx-plane. Therefore, each laser LB_iAlong the sub-carrier plane SS_i(parallel in this embodiment).

At each laser LB_iHas an F-axis collimator lens FL arranged on the optical path_i. In the present embodiment, the F-axis collimator lens FL₁～FL₇Have the same structure. In the present embodiment, in the illustrated coordinate system, a plano-convex cylindrical lens in which a flat surface (incident surface) is oriented in the negative y-axis direction and a curved surface (output surface) is oriented in the positive y-axis direction is used as the F-axis collimator lens FL_i. F-axis collimating lens FL_iThe outer edge of the y-axis positive direction side of the cross section parallel to the yz plane is arranged to draw an arc so that the laser beam LB_iIs collimated by diffusion in the F-axis direction.

After passing through an F-axis collimating lens FL_iLaser LB of_iIs provided with an S-axis collimating lens SL_i. In the present embodiment, the S-axis collimator lens SL₁～SL₇Have the same structure. In the present embodiment, in the illustrated coordinate system, a plano-convex cylindrical lens in which a flat surface (incident surface) is oriented in the negative y-axis direction and a curved surface (output surface) is oriented in the positive y-axis direction is used as the S-axis collimator lens SL_i. S-axis collimating lens SL_iThe outer edge of the positive y-axis direction side of the cross section parallel to the xy plane is arranged to draw an arc so that the slave laser diode LD_iOutput laser LB_iIs collimated by diffusion in the S-axis direction.

After passing through the S-axis collimating lens SL_iLaser LB of_iOn the optical path of (A), a reflecting mirror M is arranged_i. Each reflector M_iThe reflection surface has a normal vector orthogonal to the z-axis and 45 DEG to the positive x-axis direction and the negative y-axis direction. Mirror M_iThe reflecting surface of (2) reflects the laser beam LB_iThe traveling direction is changed from the positive y-axis direction to the positive x-axis direction (bending), and the S-axis is changed from a state parallel to the x-axis to a state parallel to the y-axis.

These respective mirrors M_iArranged from the laser diodes LDi to the mirrors M_iOptical path LM of_iAre all equal. By means of mirrors M_iReflected laser light LB_iAre arranged parallel to each other in a plane parallel to the zx-plane.

At the time of passing through the reflecting mirror M_iReflected laser light LB_iThe condenser lens FL is disposed on the optical path. In the present embodiment, in the illustrated coordinate system, a plano-convex lens in which a curved surface (incident surface) is oriented in the negative x-axis direction and a flat surface (output surface) is oriented in the positive x-axis direction is used as the condenser lens FL.

The condenser lens FL is arranged such that the outer edge on the x-axis negative direction side of the cross section parallel to the xy plane describes an arc, and the outer edge on the x-axis negative direction side of the cross section parallel to the zx plane describes an arc. Therefore, the condenser lens FL (1) will pass through the mirror M_iReflected laser light LB_iCondensing their optical axes to intersect at 1 point, and (2) passing these laser beams LB_iThe beams are condensed to reduce their beam diameters.

Laser beam LB transmitted through condenser lens FL_iAt the optical axis cross point OF, an incident end face OF provided with an optical fiber OF_I. Optical fiber OF with incident end face OF_IThe laser beams LB are routed in the negative x-axis direction and condensed by a condenser lens FL_iFrom the incident end face OF_IIs incident on the optical fiber OF. That is, each laser diode LD_iGenerated laser light LB_iOptically coupled to the laser light transmitted within the optical fiber.

(F-axis collimator lens FL_iConfiguration and coupling efficiency of

A laser module according to one aspect of the present invention is characterized in that each F-axis collimator lens FL_iThe configuration of (2). More specifically, the laser module 1 of the present embodiment is characterized by being connected to a laser diode LD₁Corresponding F-axis collimating lens FL₁The configuration of (2). This feature of the laser module 1 is explained with reference to fig. 2 to 4.

Fig. 2 is a three-dimensional view (top view, front view, and left view) of the laser module 1. In the laser module 1 shown in fig. 2, (1) the side surface along the zx plane located on the negative y-axis side is referred to as the front surface of the laser module 1, and (2) the side surface along the yz plane located on the positive x-axis side is referred to as the left side surface of the laser module 1.

Fig. 3 (a) is a schematic diagram of a unit optical system in which n is 4 among the unit optical systems included in the laser module 1. Fig. 3 (b) is a schematic diagram of a unit optical system in which n is 1 among the unit optical systems included in the laser module 101 of the comparative example shown in fig. 7. Fig. 3 (c) is a schematic diagram illustrating a unit optical system in which n is 1 among the unit optical systems included in the laser module 1 in a plan view. The unit optical system having i equal to 4 is an optical path length LO in the unit optical system provided in the laser module 1_iThe unit optical system of the intermediate value is used as a reference when the laser module 1 is installed. The unit optical system having i equal to 1 is an optical path length LO in the unit optical system provided in the laser module 1_iThe longest unit optical system, and is the unit optical system that includes the features of the laser module 1. Therefore, in the present embodiment, the F-axis collimator lens FL is used as a pair of unit optical systems with i 1 and 4_iThe configuration of (a) will be explained.

In fig. 3, (a) to (c) do not include information on the F axis of the optical path of each unit optical system. Therefore, in fig. 3 (a) to (c), the F-axis collimator lens FL included in each unit optical system is omitted_iTo illustrate (a).

A straight line RR' shown in fig. 3 (a) to (c) represents the mirror M provided in each unit optical system_iThe position of the reflecting surface of (2). This is for simplifying the top view to make the laser LB_iIs easy to understand. As a result, in fig. 3 (a) to (c), the unit optical systems are linearly expanded without bending the optical path.

A straight line EE' shown in fig. 3 (a) to (c) indicates the laser diode LD provided in each unit optical system_iThe straight line II' represents the incident end face OF OF the optical fiber OF_IThe position of (a). In fig. 3 (a) to (c), the arrows shown on the straight line EE' indicate the laser diodes LD_iLaser beam LB at the emission end face of (1)_iSpot size SP of_EIn the condenser lens FLThe arrows in the drawing indicate the laser beam LB at the entrance surface of the condenser lens FL_iSpot size SP of_FThe arrow illustrated on the line II' indicates the incident end face OF_ILaser LB of_iSpot size SP of_I. Spot size SP_ECan also be expressed as laser LB_iThe width of the near field pattern on the S-axis (x-axis in the coordinate system shown in fig. 1) and the emitter size ES described in the claims₁And (7) corresponding. In the present embodiment, the spot size SP is set_FUsing laser light LB at the entrance face of the condenser lens FL_iThe spot size of (a). However, as the spot size SP_FThe laser beam LB at the exit surface of the condenser lens FL may be used_iThe spot size of (a). In addition, the spot size SP is also schematically illustrated in fig. 2_F。

FIG. 4 (a) shows the laser beams LB incident on the condensing lens FL which is commonly provided in the laser module 1 and the laser module 101 shown in FIG. 7_iThe illuminance distribution map of (a). FIG. 4 (b) shows an incidence plane OF OF an optical fiber OF provided in the laser module 101_IEach laser LB in (1)_iThe angular distribution of (c). FIG. 4 (c) shows an incidence plane OF OF an optical fiber OF provided in the laser module 1_IAngle profile of each laser in (1). The laser module 101 is a comparative example of the laser module 1. In the following description, the laser module 101 is used in a part thereof. Fig. 7 is a perspective view of the laser module 101.

Here, first, a problem of the laser module 101 will be described, and then, a case where the laser module 1 can eliminate the problem will be described.

As shown in fig. 2, the slave laser diodes LD_iTo each S-axis collimating lens SL_iAre respectively set as the collimation length LC_i。

In the laser module 101, an S-axis collimator lens SL₁～SL₇Are respectively configured as a collimation length LC₁～LC₇Are all aligned with the S axis_iThe focal lengths (specific distances SL described in the claims) of the lenses are uniform. Therefore, the slave laser diode LD₁～LD₇Respectively output laser LB₁～LB₇Through an S-axis collimating lens SL₁～SL₇But collimated so that the respective optical paths are parallel.

For example, as shown in fig. 3 (a), when a detailed description is given of the unit optical system with i equal to 4, the slave laser diode LD is used as an example₄Laser LB of each point output of emitter₄Collimating lens SL with prescribed diffusion angle to S axis₄Is incident on the incident surface of the collimating lens SL at the S axis₄Is refracted at a predetermined angle with respect to the reflection surface, and collimates the lens SL from the S axis in a state where the optical paths are parallel₄Is output from the output surface. Here, the light is output from the end of the emitter and passes through the S-axis collimating lens SL₄Parallel light converted laser LB₄Direction of transmission and laser LB₄The angle formed by the transmission direction of the principal ray of (a) is an angle α. In addition, the laser light LB will be output from a certain point of the emitter as follows₄Light whose optical path is in an outward state as such is called divergent light. In contrast, the light having its optical path in the inward direction is hereinafter referred to as "received light".

Through an S-axis collimating lens SL₄And becomes the laser LB of the parallel light₄Collimating lens SL from S axis₄Distance LL from the lens₄The incident surface of the condenser lens FL of (1) is incident thereon, refracted at a predetermined angle between the incident surface and the reflection surface of the condenser lens FL, and output from the exit end surface of the condenser lens FL as a converged light with its optical path facing inward.

Spot size SP in condenser lens FL_FCaused by the angle alpha mentioned above, depending on the distance LL between the lenses_iAnd becomes larger. Obviously, this is due to LL_itan α depends on the inter-lens distance LL_iAnd becomes larger. Thus, the spot size SP_FDistance LL between lenses_iThe smallest i is the smallest in the case of 7, the distance LL between the lenses_iThe maximum value i is 1 (see fig. 4 (a)).

Here, the case where i is 4 has been described as an example, but the case where i is 1 to 3, 5 to 7 includes the inter-lens distance LL_iResulting in a spot size SP_FUnlike the case where i is 4The same applies to all points. Thus, the slave laser diode LD_iOutput laser LB_iAnd is optically coupled to the laser light propagating inside the optical fiber OF. In the present specification, the term "coupling efficiency" refers to the coupling efficiency of the laser diode LD_iOutput laser LB_iAnd the coupling efficiency with the laser light propagating inside the optical fiber OF.

In the laser module 101 thus configured, the spot size SP_FDistance LL between lenses_iThe smallest i is the smallest in the case of 7, the distance LL between the lenses_iThe maximum i is 1. As a result, the laser beam LB is used_iTo the incident plane OF_IThe largest incident angle among the incident angles at the time of incidence is defined as an angle β_iIn the case of angle beta₁At an angle beta₁～β₇Medium to maximum.

Presence of laser light LB_iTo the incident plane OF_IThe larger the incident angle at the time of incidence, the larger the laser LB_iThe coupling efficiency with the laser light propagating through the optical fiber OF tends to decrease. Therefore, in the comparative laser LB₁～LB₇In the case of coupling efficiency of (2), laser LB₁～LB₃Is lower than the laser LB as a reference in the case of designing the laser module 1₄The coupling efficiency of (2) is more frequent. In addition, in the comparative laser LB₁～LB₃In the case of coupling efficiency of (2), laser LB₁According to the laser LB₂Laser LB₃The order of (a) becomes higher.

Therefore, in the laser module 1, attention is paid to the laser beam LB having the lowest coupling efficiency in the laser module 101₁Collimating lens SL with S axis₁Of the collimation length LC₁Collimating lens SL greater than S axis_iIn such a way that the S-axis collimates the lens SL₁Is shifted to the positive y-axis direction side (see fig. 2).

That is, as shown in fig. 3 (c), the unit optical system in the case where i of the laser module 1 is compared with the unit optical system in the case where i of the laser module 101 shown in fig. 3 (b) is 1, and the S-axis collimator lens SL is provided₁Is located away from the emission end face of the laser diode LD 1.

As a result, the slave laser diode LD₁Output and pass through an S-axis collimating lens SL₁Refracted laser light LB₁Not parallel light, but with laser light LB₁The main light ray transmission direction of (a) forms a beam-receiving light of an angle alpha. Therefore, the spot size SP in the unit optical system in the case where i is 1 in the laser module 1_FSmaller than the spot size SP in the unit optical system in the case where i is 1 in the laser module 101_F. That is, the angle β in the unit optical system in the case where i in the laser module 1 is 1_iIs smaller than β in the unit optical system in the case where i is 1 in the laser module 101_i. This is obvious when (b) and (c) of fig. 4 are compared.

Thus, the laser module 1 thus constructed has a collimation length LC₁～LC₇Uniform and S-axis collimating lens SL_iThe coupling efficiency can be improved compared with the laser module 101 having the same focal length.

(other preferred structures)

In the present embodiment, the collimator lens SL is configured to have a specific distance SL and an S-axis_iWhen the focal lengths of the lenses are identical (that is, when the laser beam having passed through the S-axis collimator lens is parallel light), the laser beam passes through the S-axis collimator lens SL₁Satisfy SL < LC₁Thus, the case where the coupling efficiency can be improved has been described.

However, in the laser module 1, the specific distance SL may be set smaller than the S-axis collimator lens SL_iThe focal length of (i.e., the focal length is set so that the laser beam transmitted through the S-axis collimating lens is a divergent beam). Even in this case, by being configured as an S-axis collimator lens SL₁Satisfy SL < LC₁Thereby also enabling the coupling efficiency to be improved.

In the present embodiment, the collimating lens SL is only aligned with the S axis₁Is configured to satisfy SL < LC₁The case of (a) was explained. However, it may be configured such that: in the laser module according to one aspect of the present invention, the laser diode is connected to the laserTube LD₁And laser diode LD_n(e.g. laser diode LD)₇) As the laser diode LD, a laser diode different from the laser diode_mAnd will be connected to each laser diode LD_j(j is 2-m, m is 2-n-1) corresponding to each S-axis collimating lens SL_jConfigured to satisfy SL < LC_m≤LC_j＜LC₁. For example, the S-axis collimator lens SL may be set to m 3₁～SL₃Each configured to satisfy SL < LC₃＜LC₂＜LC₁。

According to this configuration, not only for the laser LB₁For laser LB₂～LB_mThe angle β, which is the maximum value of the incident angle thereof, can also be reduced_i. Therefore, not only the laser LB can be made₁Can also improve the coupling efficiency of the laser LB₂～LB_mThe coupling efficiency of (2) is improved.

Further, the following may be configured: in the laser module according to one aspect of the present invention, the specific distance SL is set from each laser diode LD_iOutput and pass through respective S-axis collimating lenses SL_iThe optical path of each laser beam is parallel or divergent, and at least the S axis is collimated by the lens SL_n(e.g., S-axis collimating lens SL)₇) Configured to satisfy LC_n< SL (e.g. LC₇＜SL)。

On the laser LB_iAngle beta of (1)_iWith laser LB_iThere is a trade-off relationship between spot size. I.e. the angle beta cannot be made_iAnd laser LB_iThe spot size of (a) is reduced beyond a limit. Thus, at the angle β_iIf the spot size of the laser beam is too small, the spot size of the laser beam may become too large, and as a result, the laser beam LB may be present_iThe coupling efficiency of (2) is reduced.

According to the above configuration, the laser beam LB can be prevented_iAngle beta of_iBecomes too small, and thus the laser beam LB can be prevented_iThe coupling efficiency is reduced. Further, by adjusting the curvature of the condenser lens FL, the laser beams LB can be adjusted_iAngle beta of_i. However, when this adjustment method is used, there are laser beams LB_iAny one of the laser LBs_iAngle beta of_i(e.g., laser LB)_nAngle beta of_n) And becomes too small. This is because the laser module 1 is provided with n laser beams LB_iAnd a condenser lens FL for collecting light. According to the above configuration, by reducing each laser beam LB_iThe angle β preferable for not reducing the coupling efficiency can be obtained by making the incident angles uniform_iAnd spot size SP_ITherefore, the above-described problems can be prevented.

Further, the following may be configured: in the laser module according to one aspect of the present invention, the specific distance SL is set from each laser diode LD_iOutput and pass through respective S-axis collimating lenses SL_iThe last laser LB_iBecomes a light beam and collimates at least the S axis with the lens SL_nConfigured to satisfy SL < LC_n。

There may also be a specific distance SL set to pass through each S-axis collimator lens SL_iThe last laser LB_iThe light is collected. In this way, each laser LB_iWhen a specific distance SL is set for the light converging mode, the collimating lenses SL may pass through the respective S axes_iThe last laser LB_iSpot size SP at the condenser lens FL_FWith the distance LL between the lenses_iIncreasing and decreasing.

Laser diode LD_nConfigured to interact with other laser diodes LD₁～LD_n－1In contrast, the distance between lenses LL_n(optical path LO)_n) And shortest. Therefore, each laser LB_iWhen the specific distance SL is set to receive the light, the slave laser diode LD_nSpot size of output laser and slave laser diode LD_nThe spot size of the laser beam output from the other laser diodes is likely to be larger than that of the laser beam output from the other laser diodes, that is, the incident angle is likely to be larger.

According to this configuration, the distance SL is set to be a specific distance so as to be a minimum beamIn this case, each laser beam LB can be reduced_nTo the incident plane OF_IAngle of incidence (i.e. angle beta)_i). Therefore, the optical path LO can be reduced_iDifferent respective laser LB_iTo the incident plane OF_IThe difference in incident angle of (2).

Further, the following may be configured: in each laser LB_iA laser module with a specific distance SL set for receiving light beams, and a laser diode LD₁And laser diode LD_nAll different laser diodes as laser diodes LD_mAnd will be connected to each laser diode LD_j(j is m is more than or equal to j is less than or equal to n-1, m is 2 is more than or equal to m is less than or equal to n-1) corresponding to each S-axis collimating lens SL_jConfigured to satisfy SL < LC_m≤LC_j＜LC_n. For example, the S-axis collimator lens SL may be set to m 5₅～SL₇Each configured to satisfy SL < LC₅＜LC₆＜LC₇。

According to this configuration, not only for the laser LB_nFor laser LB_m～LB_n－1The OF to the incident surface can be reduced_IAngle of incidence (i.e. angle beta)_i). Therefore, not only the laser LB can be made_nCan also improve the coupling efficiency of the laser LB_m～LB_n－1The coupling efficiency of (2) is improved.

Further, the following may be configured: in each laser LB_iA laser module having a predetermined distance SL for receiving light, and at least an S-axis collimating lens SL₁Configured to satisfy LC₁＜SL。

Laser diode LD₁Configured to interact with other laser diodes LD₂～LD_nIn contrast, the optical path LO₁The longest. Therefore, the collimating lens SL passes through each S axis_iThe last laser LB_iWhen the mode of receiving the light is set, the slave laser diode LD₁Output laser and slave laser diode LD₁Angle beta of laser beam output from other laser diode_iIt is easy to be small.

According to the above structure, canCan prevent laser LB₁Angle beta of₁Becomes too small, and thus the laser beam LB can be prevented₁The coupling efficiency is reduced. Further, by adjusting the curvature of the condenser lens FL, it is possible to adjust each laser beam LB_iAngle beta of_i. However, when this adjustment method is used, there are laser beams LB_iAny one of the laser LBs_iAngle beta of_i(e.g., laser LB)₁Angle beta of₁) And becomes too small. This is because the laser module 1 is provided with n laser beams LB_iAnd a condenser lens FL for collecting light. According to the above configuration, by reducing each laser beam LB_iThe angle β preferable for reducing the coupling efficiency can be obtained at the same time as the difference in the incident angle of (i) s (i.e., the incident angles are made uniform)_iAnd spot size SP_ITherefore, the above-described problems can be prevented.

Further, it is preferable that: as described above, the laser module 1 includes n mirrors M_iEach mirror M_iConfigured to apply laser light LB_iThe optical paths of (a) are bent at predetermined angles (90 ° in the present embodiment).

With this configuration, the laser diodes LD are driven by the respective laser diodes_iThe optical path to the optical fiber OF is reflected by the respective mirrors M_iBent to a specified angle. Therefore, the laser module 1 can shorten its length. Further, the length in the laser module 1 refers to a dimension with respect to a direction along the central axis OF the optical fiber OF (x-axis direction in the coordinate system illustrated in fig. 1) among dimensions OF the laser module.

Further, it is preferable that: as described above, the laser module 1 further includes a substrate having a mounting surface S on which the laser diodes LD are mounted_iAnd each S-axis collimating lens SL_iAnd each reflector M_iThe mounting surface S includes at least n sub-mounting surfaces SS each having a stepwise height decreasing as the sub-mounting surface approaches the optical fiber_iOn each sub-carrier plane SS_iA corresponding laser diode LD is mounted thereon_iS-axis collimating lens SL_iAnd a mirror M_i。

For sub-carrier planes SS of different heights_iEach of which isBy mounting a laser diode LD_iS-axis collimating lens SL_iAnd a mirror M_iThereby enabling each laser LB_iAre different in height, and the above-mentioned laser beams LB_iFor from each laser diode LD_iEach laser LB outputted_iThrough respective S-axis collimating lenses SL_iAnd is reflected by each mirror M_iAnd bending the light path.

Further, the following may be configured: in the laser module according to one embodiment of the present invention, each S-axis collimating lens SL is provided_iIs set as a curvature r_iAt least with the laser diode LD₁Corresponding S-axis collimating lens SL₁Curvature r of₁And laser diode LD_nCorresponding S-axis collimating lens SL_nCurvature r of_nAny one of the collimating lenses has a different curvature from the other collimating lenses.

The following may be configured: a laser module according to one aspect of the present invention replaces the collimating length LC in the laser module 1₁And collimation length LC_nIs different from the specific distance SL, and the curvature r is made₁And curvature r_nAny one of the collimating lenses has a different curvature from the other collimating lenses. According to this structure, the laser module functions and makes the collimation length LC₁And collimation length LC_nThe same effect as the laser modules 1 of which the specific distance SL is not equal.

Further, it is preferable that: on the basis of the laser module described above, at least the curvature r₁Less than the curvature of the other collimating lenses described above.

According to this configuration, the collimating lens SL is set to pass through each S-axis_iThe last laser LB_iWhen the light becomes parallel light or divergent light, the collimator lens SL functions as a collimator lens for at least the S axis₁Configured to satisfy SL < LC₁The same effect as in the case of (1).

Further, the following may be configured: in the laser module according to one aspect of the present invention, each laser diode LD is provided_iThe emitter size ES is the size of the emitter_iAt least the emitter dimension ES₁And emitter size ES_nThe emitter size of any one of the laser diodes is different from that of the other laser diodes.

The following may be configured: a laser module according to one aspect of the present invention replaces the collimating length LC in the laser module 1₁And collimation length LC_nIs different from the specific distance SL, so that the emitter size ES is set₁And emitter size ES_nThe emitter size of any one of the laser diodes is different from that of the other laser diodes. According to this structure, the laser module functions and makes the collimation length LC₁And collimation length LC_nThe same effect as the laser modules 1 of which the specific distance SL is not equal.

Further, it is preferable that: in the laser module according to one aspect of the present invention, at least the emitter size ES₁Smaller than the emitter size of the other laser diodes described above.

According to this configuration, the collimating lens SL is set to pass through each S-axis_iThe last laser LB_iWhen the laser beam becomes parallel light or divergent light, the laser module functions as a collimator lens SL having at least an S axis₁Configured to satisfy SL < LC₁The same effect as in the laser module 1.

(embodiment 1)

A laser module 1 as embodiment 1 of the present invention will be explained with reference to fig. 5. The laser module 1 of the present embodiment is obtained by increasing the number of unit optical systems from n 7 to n 13 on the basis of the structure of the laser module 1 shown in fig. 1.

FIG. 5 (a) shows the coupling efficiency and the collimation length LC in the unit optical system provided in the laser module 1 of the present embodiment_iThe associated graph of (2). Fig. 5 (b) shows a preferred collimation length LC for each unit optical system provided in the laser module 1 of the present embodiment_iGraph of (a).

As can be seen from FIG. 5 (a), by making each collimation length LC_i(i is 1, 3, 7, 10, 13) is varied within a range of 9mm to 10.5mm, and each laser LB is varied_iThe coupling efficiency of (2) varies. According to FIG. 5(a) As a result, the preferred collimation length LC is obtained for each of the cases where i is 1, 3, 7, 10, and 13_iAnd plotted against i to yield (b) of fig. 5. In addition, in fig. 5 (b), the preferred collimation length LC will be fitted by the least square method_iAnd the straight line obtained is drawn with a dashed line.

As can be seen from fig. 5 (b): preferred collimation length LC with respect to i-7 to be used as a reference in designing the laser module 1₇(9.9 mm) as a reference value, the larger i is, the shorter the collimation length LC is_iThe smaller i, the longer the collimation length LC_iThereby, the coupling efficiency can be improved.

In the above-described embodiment, the collimating lens SL is aligned with respect to the S axis_iA part of the S-axis collimating lens SL_iThe case where the position of (c) is not equal to the specific distance SL has been explained. However, in the laser module 1 according to one embodiment of the present invention, the S-axis collimating lens SL may be used_iIs not equal to the specified distance SL. In this case, each collimation length LC is preferable_iSatisfy LC₁＞LC₂＞···＞LC_i＞···＞LC₁₂＞LC₁₃。

(embodiment 2)

A laser module as embodiment 2 of the present invention will be explained with reference to fig. 6. The laser module 1 of the present embodiment is based on the configuration of the laser module 101 shown in fig. 7, and increases the number of unit optical systems from n-7 to n-13, and then makes the S-axis collimator lens SL_iCurvature r of_iAnd (c) varying.

FIG. 6 (a) shows the coupling efficiency and curvature r in the unit optical system of the laser module of the present embodiment_iThe associated graph of (2). Fig. 6 (b) shows a curvature r preferable for each unit optical system provided in the laser module 1 of the present embodiment_iGraph of (a).

As can be seen from fig. 6 (a): by making each curvature r_i(i is 1, 3, 7, 10, 13) is varied within a range of 6.2mm to 6.9mm, and each laser beam LB is varied_iThe coupling efficiency of (2) varies. According to the figureAs a result of (a) of fig. 6, a preferable curvature r was obtained for each of the cases where i was 1, 3, 7, 10, and 13_iAnd plotted against i to yield (b) of fig. 6. In fig. 6 (b), the curvature r is preferably fitted by the least square method_iThe resulting straight line is drawn with a dashed line.

As can be seen from (b) of fig. 6: preferred curvature r with respect to i-7 to be used as a reference in designing the laser module 1_i(6.7 mm) as a reference value, the larger i is, the larger the curvature r is_iThe smaller i, the smaller the curvature r_iThereby, the coupling efficiency can be improved.

In the above-described embodiment, the collimating lens SL is aligned with respect to the S axis_iA part of the S-axis collimating lens SL_iCurvature r of_iThe case of being unequal to the specific distance SL has been explained. However, in the laser module 1 according to one embodiment of the present invention, the S-axis collimator lens SL may be used_iAll curvatures r of_iMutually different structures. In this case, each curvature r is preferable_iSatisfy r₁＜r₂＜···＜r_i＜···＜r₁₂＜r₁₃。

[ conclusion ]

A laser module 1 according to one embodiment OF the present invention includes an optical fiber OF, and an optical path LO corresponding to the length OF an optical path to the optical fiber OF_iN laser diodes LD with sequence from long to short of i ═ 1, 2, ·, n_iAnd n collimator lenses SL respectively disposed in the middle of the optical paths_i. In the laser module 1, each laser diode LD_iTo each collimating lens SL_iAs the collimation length LC_iAnd a laser diode LD₁Corresponding collimation length LC₁And laser diode LD_nCorresponding collimation length LC_nAt least one of (1) and the collimating lenses SL_iThe determined specific distance SL is not equal.

The laser module is composed of a plurality of laser diodes LD_iOutput and pass through each collimating lens SL_iThe latter laser light is concentratedAnd inputting the optical fiber. Each laser diode LD_iThe emitter provided has a certain size although it is small. Therefore, the incident angle of each laser beam incident on the optical fiber has a certain specific width in a predetermined angle range including a perpendicular range, depending on the size of the emitter. The specific width of the incident angle may make each laser diode LD possible_iThe coupling efficiency of the generated laser light and the laser light transmitted in the optical fiber is reduced.

In the laser module, at least the laser diode LD₁Corresponding collimation length LC₁And laser diode LD_nCorresponding collimation length LC_nIs different from the specific distance SL, the slave laser diode LD can be reduced₁Laser light output from the laser diode LD_nAn incident angle when at least any one of the output laser beams is incident on the optical fiber. In other words, the predetermined angle range including the perpendicular can be narrowed. Therefore, the laser module can improve the coupling efficiency between the laser light generated by each laser diode and the laser light propagating through the optical fiber, as compared with the conventional laser module.

Further, it is preferable that: in the laser module 1 according to one embodiment of the present invention, the specific distance SL is set from each laser diode LD_iOutput and pass through each collimating lens SL_iThe light path of each laser is parallel or divergent, at least the collimating lens SL₁Configured to satisfy SL < LC₁。

The specific distance SL is set to be from each laser diode LD_iOutput and pass through respective collimating lenses SL_iThe optical paths of the subsequent laser beams are often parallel. In addition, there may be a case where the specific distance SL is set to the above-described optical path divergence.

Laser diode LD₁Configured to interact with other laser diodes LD₂～LD_nIn contrast, the optical path LO₁The longest. Therefore, when the specific distance SL is set so that the optical path is parallel or divergent, the slave laser diode LD₁Output laser and slave laser diodeTube LD₁The incidence angle of the laser light output from the other laser diodes is larger than that of the laser light output from the other laser diodes.

According to the above configuration, when the specific distance SL is set so that the optical path is parallel or divergent, the slave laser diode LD can be reduced₁Angle of incidence in the output laser light.

Further, it is preferable that: in the laser module 1 according to one embodiment of the present invention, a laser diode LD is provided₁And laser diode LD_nAll different laser diodes as laser diodes LD_mAnd will be connected to each laser diode LD_j(j is 2. ltoreq. j. ltoreq.m) of each collimator lens SL_jConfigured to satisfy SL < LC_m≤LC_j＜LC₁。

According to the above-described structure, except for the collimator lens SL₁Besides, will be connected with the laser diode LD₂～LD_mCorresponding D collimating lens SL₂～SL_mEach also configured as a collimation length LC₂～LC_mBeyond a certain distance SL. In addition, the collimation length LC₂～LC_mThe values are set to become smaller in this order. According to this structure, except from the laser diode LD₁For the slave laser diode LD other than the output laser light₂～LD_mThe incidence angle of the laser beams outputted separately can be reduced.

Further, the following may be configured: in the laser module 1 according to one embodiment of the present invention, the specific distance SL is set from each laser diode LD_iOutput and pass through each collimating lens SL_iThe light path of each laser beam is parallel or divergent, and at least the collimating lens SL_nConfigured to satisfy LC_n＜SL。

Laser diode LD_nConfigured to interact with other laser diodes LD₁～LD_n－1In contrast, the optical path LO_nAnd shortest. Therefore, the light source is set to pass through each collimating lens SL_iWhen the optical paths of the subsequent laser beams are parallel or divergent, the slave laser diode LD_nOutput laser and slave laser diode LD_nOutside the fieldThe laser diode of (3) is likely to have a smaller incident angle than the laser light output therefrom.

Here, there is a relationship between the incidence angle of the laser beam (i.e., the number of laser beam apertures) and the spot size of the laser beam, in which when one is reduced, the other is inevitably increased. Therefore, in the slave laser diode LD_nWhen the angle of incidence of the output laser beam becomes too small, the spot size of the laser beam becomes too large, and as a result, there is a possibility that the slave laser diode LD may be present_nThe coupling efficiency of the output laser light and the laser light propagating through the optical fiber is reduced.

According to the above structure, the slave laser diode LD can be prevented_nThe incident angle of the output laser light becomes too small.

Further, the following may be configured: in the laser module 1 according to one embodiment of the present invention, the specific distance SL is set from each laser diode LD_iOutput and pass through each collimating lens SL_iThe optical path of each laser beam is converged to form at least a collimator lens SL_nConfigured to satisfy SL < LC_n。

There may also be a case where the specific distance SL is set from each laser diode LD_iOutput and pass through each collimating lens SL_iAnd the optical path of each of the subsequent laser beams is converged. When the specific distance SL is set to the above-described optical path convergence, the light may pass through each collimator lens SL_iThe spot size of each laser beam becomes farther from the collimator lens SL_iAnd becomes smaller.

Laser diode LD_nConfigured to interact with other laser diodes LD₁～LD_n－1In contrast, the optical path LO_nAnd shortest. Therefore, when the specific distance SL is set to the above-mentioned optical path convergence, the slave laser diode LD_nSpot size of output laser and slave laser diode LD_nThe spot size of the laser beam output from the other laser diodes tends to be larger than that of the laser beam output from the other laser diodes, that is, the incident angle tends to be larger.

According to the above configuration, when the specific distance SL is set to the optical path convergenceCapable of reducing the slave laser diode LD_nAngle of incidence in the output laser light.

Further, the following may be configured: in the laser module 1 according to one embodiment of the present invention, a laser diode LD is provided₁And laser diode LD_nAll different laser diodes as laser diodes LD_mAnd will be connected to each laser diode LD_j(j is m is more than or equal to j is more than or equal to n-1) corresponding to each collimating lens SL_jConfigured to satisfy SL < LC_m≤LC_j＜LC_n。

According to the above-described structure, except for the collimator lens SL_nBesides, it will also be connected to the laser diode LD_m～LD_n－1Corresponding collimating lenses SLm-SL_n－1Each respectively configured as a collimation length LC_m～LC_n－1Beyond a certain distance SL. In addition, the collimation length LC_m～LC_n－1The values are set to become smaller in this order. According to this structure, except from the laser diode LD_nFor the slave laser diode LD other than the output laser light_m～LD_n－1The incidence angle of the laser beams outputted separately can be reduced.

Further, the following may be configured: in the laser module 1 according to one embodiment of the present invention, the specific distance SL is set from each laser diode LD_iOutput and pass through each collimating lens SL_iThe optical path of each laser beam is converged to form at least a collimator lens SL₁Configured to satisfy LC₁＜SL。

Laser diode LD₁Configured to interact with other laser diodes LD₂～LD_nIn contrast, the optical path LO₁The longest. Therefore, the light source is set to pass through each collimating lens SL_iWhen the optical path of each subsequent laser beam is converged, the slave laser diode LD₁Output laser and slave laser diode LD₁The incidence angle of the laser light output from the other laser diodes is likely to be smaller than that of the laser light output from the other laser diodes.

When the incident angle becomes too small as described above, there is a possibility that the slave laser diode LD may exist₁Laser light output andthe coupling efficiency of the laser light propagating through the optical fiber is reduced. According to the above structure, the slave laser diode LD can be prevented₁The incident angle of the output laser light becomes too small.

Further, it is preferable that: the laser module 1 according to one embodiment of the present invention further includes collimator lenses SL respectively disposed in the middle of the optical paths_iN mirrors M between the optical fiber OF_iEach mirror M_iThe optical paths are arranged to be bent at predetermined angles.

According to the above structure, each laser diode LD_iThe optical path to the optical fiber is reflected by the respective mirrors M_iBent to a specified angle. Therefore, the laser module can shorten the length thereof. The length in the present laser module refers to a dimension of the laser module with respect to a direction along the central axis of the optical fiber.

Further, it is preferable that: the laser module 1 according to one embodiment of the present invention further includes a substrate B having a mounting surface S on which the laser diodes LD are mounted_iAnd each collimating lens SL_iAnd each reflector M_iThe mounting surface S includes at least n sub-mounting surfaces SS each having a stepwise height decreasing as approaching the optical fiber OF_iOn each sub-carrier plane SS_iCarries a corresponding laser diode LD_iCollimator lens SL_iAnd a mirror M_i。

For sub-carrier planes SS of different heights_iBy mounting a laser diode LD thereon_iCollimator lens SL_iAnd a mirror M_iThus, the heights of the laser beams from the laser diodes LD can be made different_iThe output laser beams pass through the collimating lenses SL_iAnd is reflected by each mirror M_iAnd bending the light path.

A laser module 1 according to one embodiment OF the present invention includes an optical fiber OF, and an optical path LO corresponding to the length OF an optical path to the optical fiber OF_iN laser diodes with sequence order of i ═ 1, 2, ·, n from long to shortLD_iAnd n collimator lenses SL respectively disposed in the middle of the optical paths_i. In the laser module 1, each collimator lens SL is disposed_iAs the curvature r_iAt least with the laser diode LD₁Corresponding collimating lens SL₁Curvature r of₁And laser diode LD_nCorresponding collimating lens SL_nCurvature r of_nAny one of the collimating lenses has a different curvature from the other collimating lenses.

The following may be configured: the laser module 1 according to one aspect of the present invention replaces the collimation length LC₁And collimation length LC_nIs different from the specific distance SL, and the curvature r is made₁And curvature r_nAny one of the collimating lenses has a different curvature from the other collimating lenses. According to this structure, the collimation length LC is realized₁And collimation length LC_nThe same effect as a laser module of which the specific distance SL is not equal.

Further, it is preferable that: in the laser module 1 according to one aspect of the present invention, at least the curvature r₁Less than the curvature of the other collimating lenses described above.

According to the above configuration, the collimating lens SL is set to pass through each collimating lens SL_iWhen the optical paths of the subsequent laser beams are parallel or divergent, at least the collimator lens SL is used₁Configured to satisfy SL < LC₁The same effect as in the case of (1).

A laser module 1 according to one embodiment OF the present invention includes an optical fiber OF, and an optical path LO corresponding to the length OF an optical path to the optical fiber OF_iN laser diodes LD with sequence from long to short of i ═ 1, 2, ·, n_iAnd n collimator lenses SL respectively disposed in the middle of the optical paths_i. In the laser module 1, each laser diode LD_iThe emitter size ES is the size of the emitter_iAt least the emitter size ES₁And emitter size ES_nThe emitter size of any one of the laser diodes is different from that of the other laser diodes.

The following may be configured: the laser module 1 according to one aspect of the present invention replaces the collimation length LC₁And collimation length LC_nIs different from the specific distance SL, so that the emitter size ES is set₁And emitter size ES_nThe emitter size of any one of the laser diodes is different from that of the other laser diodes. According to this structure, the collimation length LC is realized₁And collimation length LC_nThe same effect as a laser module of which the specific distance SL is not equal.

Further, it is preferable that: in the laser module 1 according to one aspect of the present invention, at least the emitter size ES₁Smaller than the emitter size of the other laser diodes described above.

According to the above configuration, the collimating lens SL is set to pass through each collimating lens SL_iWhen the optical paths of the subsequent laser beams are parallel or divergent, at least the collimator lens SL is used₁Configured to satisfy SL < LC₁The same effect as in the case of (1).

The present invention is not limited to the above embodiments, and various modifications can be made within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments are also included in the technical scope of the present invention.

Description of the reference numerals

1 … laser module; LD_i… a laser diode; FL_i… F-axis collimating lens; SL (Long-side)_i… S-axis collimating lens; m_i… a mirror; FL … condenser lenses; OF … optical fiber; b … backplane (baseplate); s … carrying surface; SS_i… a sub-carrier surface.