阅读说明：本技术 一种波长锁定半导体激光器系统 (Wavelength locking semiconductor laser system ) 是由 孙舒娟 俞浩 王俊 李波 胡燚文 于 2021-08-11 设计创作，主要内容包括：一种波长锁定半导体激光器系统,包括：第一光纤耦合模块至第N光纤耦合模块,第k光纤耦合模块包括第k传能光纤和若干第k半导体激光发光管；体光栅锁定模块,体光栅锁定模块包括若干第N+1半导体激光发光管、体光栅和第N+1传能光纤；光纤合束器,光纤合束器包括第一输入光纤至第N+1输入光纤、以及输出光纤；第k传能光纤与第k输入光纤与连接,第N+1传能光纤与第N+1输入光纤连接；部分反射结构,设置在输出光纤的输出端面一侧,部分反射结构用于作为若干第一半导体激光发光管至若干第N半导体激光发光管的谐振反馈结构。所述波长锁定半导体激光器系统输出光束的光谱得到窄化。(A wavelength-locked semiconductor laser system, comprising: the first optical fiber coupling module to the Nth optical fiber coupling module, the kth optical fiber coupling module comprises a kth energy transfer optical fiber and a plurality of kth semiconductor laser light emitting tubes; the body grating locking module comprises a plurality of N +1 semiconductor laser luminescent tubes, a body grating and an N +1 energy transmission optical fiber; the optical fiber combiner comprises a first input optical fiber to an N +1 th input optical fiber and an output optical fiber; the kth energy transmission optical fiber is connected with the kth input optical fiber, and the N +1 energy transmission optical fiber is connected with the N +1 input optical fiber; and the partial reflection structure is arranged on one side of the output end face of the output optical fiber and is used as a resonance feedback structure from the plurality of first semiconductor laser light emitting tubes to the plurality of Nth semiconductor laser light emitting tubes. The spectrum of the output beam of the wavelength-locked semiconductor laser system is narrowed.)

1. A wavelength-locked semiconductor laser system, comprising:

the first optical fiber coupling module to the Nth optical fiber coupling module, the kth optical fiber coupling module comprises a kth energy transfer optical fiber and a plurality of kth semiconductor laser light emitting tubes; n is an integer greater than or equal to 2, k is an integer greater than or equal to 1 and less than or equal to N;

the body grating locking module comprises a plurality of N +1 semiconductor laser luminescent tubes, a body grating and an N +1 energy transmission optical fiber;

an optical fiber combiner including first to N +1 th input fibers and an output fiber; the kth energy transmission optical fiber is connected with the kth input optical fiber, and the N +1 energy transmission optical fiber is connected with the N +1 input optical fiber;

and the partial reflection structure is arranged on one side of the output end face of the output optical fiber and is used as a resonance feedback structure from the plurality of first semiconductor laser light emitting tubes to the plurality of Nth semiconductor laser light emitting tubes.

2. A wavelength-locked semiconductor laser system as claimed in claim 1 wherein the partially reflective structure is a coated reflective layer in contact with the output end facet of the output optical fiber.

3. A wavelength-locked semiconductor laser system as claimed in claim 1 wherein said partially reflective structure comprises a partially reflective partially transmissive mirror disposed opposite an output end facet of said output optical fiber.

4. A wavelength-locked semiconductor laser system as claimed in claim 3 further comprising: and the coated antireflection layer is arranged on the output end face of the output optical fiber and is positioned between the partial reflection partial transmission mirror and the output optical fiber.

5. A wavelength-locked semiconductor laser system as claimed in any one of claims 1 to 4 wherein the partially reflective structure has a reflectivity of 5% to 20%.

6. The wavelength-locked semiconductor laser system of claim 1, wherein the bulk grating lock-in module further comprises: a central wavelength detection unit adapted to detect a central wavelength shift degree of laser light emitted by the N +1 th semiconductor laser light emitting tube; and the temperature control unit is suitable for carrying out temperature compensation on the volume grating according to the central wavelength deviation degree so as to reduce the central wavelength deviation of the laser.

7. The wavelength-locked semiconductor laser system of claim 6, wherein the temperature control unit comprises a semiconductor chilling plate in contact with the body grating, the semiconductor chilling plate adapted to chill the body grating, the semiconductor chilling plate further adapted to heat the body grating, and a feedback control adapted to adjust the degree of chilling and heating of the semiconductor chilling plate based on the degree of center wavelength shift detected by the center wavelength detection unit.

8. The wavelength-locked semiconductor laser system of claim 1, wherein the kth fiber coupling module further comprises: the k-th focusing coupling mirror unit is suitable for focusing and coupling a plurality of laser beams collimated by the k-th collimating mirrors to a k-th energy transmission optical fiber; a plurality of k45 degree reflecting mirrors, wherein the k45 degree reflecting mirrors are suitable for reflecting the laser light collimated by the k collimating mirror towards a k focusing coupling mirror unit.

9. The wavelength-locked semiconductor laser system of claim 1, wherein the bulk grating lock-in module further comprises: the N +1 th focusing coupling mirror unit is positioned between the volume grating and the N +1 th energy transmission optical fiber; a plurality of N +145 degree reflectors, wherein the N +145 degree reflectors are suitable for reflecting the laser light collimated by the N +1 degree collimator toward the volume grating.

Technical Field

The invention relates to the field of semiconductors, in particular to a wavelength locking semiconductor laser system.

Background

The semiconductor laser has the excellent characteristics of high efficiency, compact structure, wide wavelength range, low cost, high reliability and the like. However, the conventional semiconductor laser has poor spectral characteristics, poor beam quality, low direct output power and low brightness. However, some solid-state lasers and fiber lasers require the output beam of the semiconductor laser to have a narrow line width. In order to narrow the spectrum of a semiconductor laser, a bulk bragg grating (VBG) is often used as a reflective cavity mirror to form an external cavity semiconductor laser together with a high power semiconductor laser.

The commonly used semiconductor laser pump source is provided with a single-tube beam combining module and an array, and is subjected to optical fiber coupling after beam shaping to form a tail fiber output pump source. A common configuration when performing spectral narrowing is to place the volume grating (VBG) inside a single-tube module and behind the exit face of the array. In a single-tube module, each module needs to correspond to one volume grating, and each linear array also needs to correspond to one volume grating in the array, so that the number of the volume gratings used in a high-power pump source is increased, the cost is increased, and the adjustment difficulty is increased. In addition, the temperature of the volume grating is increased due to the absorption of the incident laser by the volume grating due to the glass material, and the temperature effect of the volume bragg grating material and the heating effect of the high-power-density laser cause the red shift of the bragg wavelength of the grating and further cause the red shift of the lasing wavelength of the locked semiconductor laser, so that the wavelength shift problem caused by the temperature effect of the volume bragg grating must be considered in the wavelength locking of the high-power and high-brightness semiconductor laser. When the number of the VBGs is increased, each VBG needs to be subjected to temperature control, and when the temperature of each VBG cannot be accurately controlled at the same time, different modules or linear arrays are locked at different central wavelengths, so that the spectrum of the final combined output beam is broadened.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the problem of wider spectrum of the output beam of the wavelength locking semiconductor laser system in the prior art.

In order to solve the above technical problem, the present invention provides a wavelength-locked semiconductor laser system, including: the first optical fiber coupling module to the Nth optical fiber coupling module, the kth optical fiber coupling module comprises a kth energy transfer optical fiber and a plurality of kth semiconductor laser light emitting tubes; n is an integer greater than or equal to 2, k is an integer greater than or equal to 1 and less than or equal to N; the body grating locking module comprises a plurality of N +1 semiconductor laser luminescent tubes, a body grating and an N +1 energy transmission optical fiber; an optical fiber combiner including first to N +1 th input fibers and an output fiber; the kth energy transmission optical fiber is connected with the kth input optical fiber, and the N +1 energy transmission optical fiber is connected with the N +1 input optical fiber; and the partial reflection structure is arranged on one side of the output end face of the output optical fiber and is used as a resonance feedback structure from the plurality of first semiconductor laser light emitting tubes to the plurality of Nth semiconductor laser light emitting tubes.

Optionally, the partial reflection structure is a coated reflection layer in contact with the output end face of the output optical fiber.

Optionally, the partially reflective structure comprises a partially reflective partially transmissive mirror disposed opposite the output end face of the output optical fiber.

Optionally, the method further includes: and the coated antireflection layer is arranged on the output end face of the output optical fiber and is positioned between the partial reflection partial transmission mirror and the output optical fiber.

Optionally, the reflectivity of the partial reflection structure is 5% to 20%.

Optionally, the volume grating locking module further includes: a central wavelength detection unit adapted to detect a central wavelength shift degree of laser light emitted by the N +1 th semiconductor laser light emitting tube; and the temperature control unit is suitable for carrying out temperature compensation on the volume grating according to the central wavelength deviation degree so as to reduce the central wavelength deviation of the laser.

Optionally, the temperature control unit includes a semiconductor refrigeration piece and a feedback control piece, the semiconductor refrigeration piece is in contact with the volume grating, the semiconductor refrigeration piece is suitable for refrigerating the volume grating, the semiconductor refrigeration piece is also suitable for heating the volume grating, and the feedback control piece is suitable for adjusting the refrigerating and heating degrees of the semiconductor refrigeration piece according to the central wavelength deviation degree detected by the central wavelength detection unit.

Optionally, the kth fiber coupling module further includes: the k-th focusing coupling mirror unit is suitable for focusing and coupling a plurality of laser beams collimated by the k-th collimating mirrors to a k-th energy transmission optical fiber; a plurality of k45 degree reflecting mirrors, wherein the k45 degree reflecting mirrors are suitable for reflecting the laser light collimated by the k collimating mirror towards a k focusing coupling mirror unit.

Optionally, the N +1 th collimating mirror and the N +1 th focusing coupling mirror unit are located between the volume grating and the N +1 th energy transmitting fiber; a plurality of N +145 degree reflectors, wherein the N +145 degree reflectors are suitable for reflecting the laser light collimated by the N +1 degree collimator toward the volume grating.

The technical scheme of the invention has the following advantages:

according to the wavelength locking semiconductor laser system provided by the technical scheme of the invention, for the first optical fiber coupling module to the Nth optical fiber coupling module, the partial reflection structure is used as a resonance feedback structure from a plurality of first semiconductor laser light emitting tubes to a plurality of Nth semiconductor laser light emitting tubes, and no body grating is arranged in the first optical fiber coupling module to the Nth optical fiber coupling module. The body grating locking module is internally provided with a body grating as a resonance feedback structure of a plurality of (N +1) th semiconductor laser luminescent tubes. The laser beam transmitted by the body grating enters the (N +1) th energy-transferring optical fiber and the optical fiber beam combiner in sequence in the state that the body grating locks a plurality of (N +1) th semiconductor laser light-emitting tubes, the laser beam is reflected back to a part of laser by the partial reflection structure when reaching the output end surface of the output optical fiber, the reflected laser sequentially returns to the output optical fiber and the input optical fiber (from the first input optical fiber to the N +1 th input optical fiber), the reflected laser is divided into a plurality of reflected laser beam splitting by the first input optical fiber to the N +1 th input optical fiber, the plurality of reflected laser beam splitting respectively and correspondingly enters the first energy transmission optical fiber to the N +1 th energy transmission optical fiber, and then enters the first optical fiber coupling module to the N optical fiber coupling module and the bulk grating locking module, and the reflected laser beam entering the kth optical fiber coupling module is split to lock the kth semiconductor laser luminous tube in the kth optical fiber coupling module. Secondly, for any kth optical fiber coupling module from the first optical fiber coupling module to the Nth optical fiber coupling module, a laser beam output by the kth optical fiber coupling module sequentially passes through a kth energy transfer optical fiber and an optical fiber combiner, the laser beam output by the kth optical fiber coupling module is reflected to a part of laser by a partial reflection structure when reaching the output end face of an output optical fiber, the reflected laser sequentially returns to the output optical fiber and the optical fiber combiner, and is also divided into (N +1) paths of reflected laser beam splitting by a first input optical fiber to an N +1 th input optical fiber, the reflected laser beam splitting respectively enters a first energy transfer optical fiber to an N +1 th energy transfer optical fiber, wherein the reflected laser from the first energy transfer optical fiber to the N1 th energy transfer optical fiber respectively returns to the first optical fiber coupling module to the Nth optical fiber coupling module, and the reflected laser from the N +1 th energy transfer optical fiber returns to a bulk grating locking module, therefore, for the first fiber coupling module to the Nth fiber coupling module and the bulk grating locking module, feedback light received by each module is light emitted by the module and light from the rest N modules, so that the modules are interlocked. The body grating locking module adopts the body grating to lock the wavelength, so that the locking state of the body grating locking module is not interfered by reflected light of a partial reflection structure, the locking of the body grating locking module on the first optical fiber coupling module to the Nth optical fiber coupling module is realized, the locking wavelength of the first optical fiber coupling module to the Nth optical fiber coupling module is completely consistent with the locking wavelength of the body grating locking module, and the spectrum of the output light beam of the wavelength locking semiconductor laser system is narrowed.

Secondly, the laser beam combining is carried out by using the optical fiber beam combiner, and the output power of the output optical fiber is increased by N +1 times.

Further, the volume grating locking module further comprises: a central wavelength detection unit adapted to detect a central wavelength shift degree of laser light emitted by the N +1 th semiconductor laser light emitting tube; and the temperature control unit is suitable for carrying out temperature compensation on the volume grating according to the central wavelength deviation degree so as to reduce the central wavelength deviation of the laser. The central wavelength drift of the bulk grating locking module is controlled. When the central wavelength drift of the bulk grating locking module is controlled, the locking central wavelengths of all the first fiber coupling modules to the Nth fiber coupling module are consistent and synchronously changed, so that the widening of the final combined output light spectrum caused by the fact that different modules are locked at different central wavelengths is avoided, namely the whole system can realize the adjustability and controllability of the locking central wavelength under the condition that the spectrum width is consistent with the spectrum width of a single bulk grating locking module.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a schematic diagram of a wavelength-locked semiconductor laser system according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a wavelength-locked semiconductor laser system according to another embodiment of the present invention;

fig. 3 is a schematic structural diagram of a kth fiber coupling module according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a bulk grating locking module according to an embodiment of the present invention.

Detailed Description

An embodiment of the present invention provides a wavelength-locked semiconductor laser system, with reference to fig. 1, 2 and 3, including:

the first optical fiber coupling module G1 to the Nth optical fiber coupling module Gn, wherein the kth optical fiber coupling module comprises a kth energy transfer optical fiber and a plurality of kth semiconductor laser light emitting tubes; n is an integer greater than or equal to 2, k is an integer greater than or equal to 1 and less than or equal to N;

a bulk grating locking module S including several N +1 semiconductor laser emitting tubes, a bulk grating 22 and an N +1 energy transfer optical fiber C_N+1；

The optical fiber combiner 10, the optical fiber combiner 10 includes first to N +1 th input optical fibers and an output optical fiber 101; the kth energy transmission optical fiber is connected with the kth input optical fiber, and the N +1 energy transmission optical fiber is connected with the N +1 input optical fiber;

and a partial reflection structure disposed on an output end surface side of the output optical fiber 101, the partial reflection structure being used as a resonance feedback structure for the first semiconductor laser light emitting tube to the Nth semiconductor laser light emitting tube.

As shown in FIG. 1, the first fiber coupling module G1 includes a first energy-transmitting fiber C1 and a plurality of first semiconductor laser light emitting tubes, the second fiber coupling module G1 includes a second energy-transmitting fiber C2 and a plurality of second semiconductor laser light emitting tubes, and the Nth fiber coupling module G_NComprising an Nth energy transmitting optical fiber C_NAnd the kth optical fiber coupling module comprises a kth energy transmission optical fiber and a plurality of kth semiconductor laser light-emitting tubes in sequence.

The plurality of kth semiconductor laser light emitting tubes are semiconductor laser arrays; or each of the plurality of k-th semiconductor laser emitting tubes is a single tube.

The N +1 th semiconductor laser light emitting tubes are semiconductor laser arrays; or each of the plurality of N +1 th semiconductor laser light-emitting tubes is a single tube.

In one embodiment, referring to fig. 1, the partially reflective structure is a coated reflective layer 102 in contact with the output end face of the output optical fiber 101, which makes the structure of the partially reflective structure simple.

In another embodiment, referring to FIG. 2, the partially reflective structure includes a partially reflective partially transmissive mirror 112b disposed opposite the output end face of the output fiber 101. Further, the partially reflecting structure further includes: and the coated anti-reflection layer 112 is arranged on the output end face of the output optical fiber 101, and the coated anti-reflection layer 112 is positioned between the partial reflection partial transmission mirror 112b and the output optical fiber 101. The coated anti-reflection layer 112 is adapted to increase the transmittance of the output end face of the output optical fiber 101. If the coated anti-reflection layer 112 is not provided, the output end surface of the output optical fiber 101 will have a part of reflection, and the difference of the output end surfaces of different output optical fibers 101 will cause the reflection to have different magnitudes. In the present application, the coated anti-reflection layer 112 is provided to increase the transmittance of the output end face of the output optical fiber 101, and mainly depends on the partially reflective partially transmissive mirror 112b for reflection, and the reflectance of the partially reflective partially transmissive mirror 112b is easily and precisely controlled.

In one embodiment, the partially reflective structure has a reflectivity of 5% to 20%, such as 5%, 8%, 10%, 15%, or 20%. Has the advantages that: if the reflectivity of the partial reflection structure is less than 5%, less laser light participates in the competition mode, which increases the difficulty of laser wavelength locking, and if the reflectivity of the partial reflection structure is greater than 20%, less light is transmitted by the partial reflection structure, which results in lower output laser power. Referring to fig. 1, the reflectivity of the coated reflective layer 102 is 5% to 20%. Referring to fig. 2, the partially reflective partially transmissive mirror 112b has a reflectivity of 5% to 20%.

Referring to fig. 3, a kth fiber coupling module of any one of the first to nth fiber coupling modules, the kth fiber coupling module including: a plurality of kth semiconductor laser luminous tubes 110k and kth energy transmission optical fibers C_kThe kth fiber coupling module further includes: the k-th focusing coupling mirror unit is suitable for focusing and coupling a plurality of laser beams collimated by the k-th collimating mirrors to a k-th energy transmission optical fiber; a plurality of k45 degree reflecting mirrors 140k, wherein the k45 degree reflecting mirrors 140k are suitable for directing the laser light collimated by the k collimating mirror to the k focusing coupling mirrorThe cell is reflective. Each k-th collimating mirror includes a k-th slow axis collimating mirror 130k and a k-th fast axis collimating mirror 120 k. The plurality of kth fast axis collimating lenses 120k are arranged in the fast axis direction and have a small height difference, the plurality of kth fast axis collimating lenses 120k are further arranged in sequence in the slow axis direction, and the plurality of kth slow axis collimating lenses 130k are arranged in sequence in the slow axis direction. In the k-th collimating mirror, a k-th fast axis collimating mirror 120k is located between the k-th semiconductor laser emitting tube 110k and the k-th slow axis collimating mirror 130 k. The kth fast axis collimating lens 120k is adapted to collimate the laser beam output by the kth semiconductor laser emitting tube 110k in the fast axis direction, and the kth slow axis collimating lens 130k is adapted to collimate the laser beam in the slow axis direction. After the k-th fast axis collimating lens 120k collimates the laser beam in the fast axis, the k-th slow axis collimating lens 130k collimates the laser beam in the slow axis direction. The number of the kth slow axis collimating mirrors 130k is the same as the number of the kth semiconductor laser emitting tubes 110k, and the number of the kth fast axis collimating mirrors 120k is the same as the number of the kth semiconductor laser emitting tubes 110 k. An angle of 45 degrees is formed between a normal direction of the k45 th reflecting mirror 140k and an incident direction of laser light incident on the k45 th reflecting mirror 140k, the k45 th reflecting mirror 140k is adapted to reflect the laser light collimated by the k slow axis collimating mirror 130k and the k fast axis collimating mirror 120k toward the k focusing coupling mirror unit, and the k45 th reflecting mirror 140k deflects an optical path of the laser light by 90 degrees. The number of the k45 reflecting mirrors 140k is the same as the number of the k slow axis collimating mirrors 130 k. The plurality of k 45-degree reflecting mirrors 140k have height difference in the fast axis direction, so that the plurality of k 45-degree reflecting mirrors 140k do not block the laser beams reflected by the reflecting mirrors 140k on the light path, and each laser beam is reflected by the corresponding k 45-degree reflecting mirror 140k and then enters the k focusing coupling mirror unit. A kth semiconductor laser emitting tube 110k corresponds to a kth fast axis collimator 120k, a kth slow axis collimator 130k, and a kth 45 ° reflector 140 k.

Referring to fig. 3, the kth focusing coupling mirror unit is adapted to focus the collimated laser and couple the collimated laser to the kth energy transmitting fiber, and the kth focusing coupling mirror unit focuses the collimated laser to make the size of the focused spot smaller than the kth energy transmitting fiber C_kSo that the laser beam can pass through the kth energy-transmitting fiber C_kAnd (5) transmitting. Kth focusThe coupling mirror unit comprises a k fast axis focusing coupling mirror 150k and a k slow axis focusing coupling mirror 160k, the k fast axis focusing coupling mirror 150k being located between the number k45 ° of mirrors 140k and the k slow axis focusing coupling mirror 160 k. The kth focusing coupling mirror unit may also be a spherical lens.

For the first optical fiber coupling module to the Nth optical fiber coupling module, the partial reflection structure is used as a resonance feedback structure from the plurality of first semiconductor laser light emitting tubes to the plurality of Nth semiconductor laser light emitting tubes, and body gratings are not arranged in the first optical fiber coupling module to the Nth optical fiber coupling module.

Referring to fig. 4, the bulk grating lock module S includes: a plurality of N +1 semiconductor laser luminous tubes 110', a body grating 22 and an N +1 energy transmission optical fiber C_N+1The volume grating locking module further comprises: a plurality of N +1 st collimating mirrors and N +1 st focusing coupling mirror units 156, the N +1 st focusing coupling mirror units 156 are positioned on the volume grating 22 and the N +1 st energy transmission fiber C_N+1Meanwhile, the (N +1) th focusing and coupling mirror unit 156 is adapted to focus and couple the laser beam transmitted by the volume grating 22 to the (N +1) th energy transmission fiber C_N+1(ii) a A number of N +145 ° mirrors 140 ', said N +145 ° mirrors 140' being adapted to reflect the laser light after being collimated by the N +1 th collimator mirror towards the volume grating 22. Each of the N +1 th collimating mirrors includes an N +1 th slow axis collimating mirror 130 'and an N +1 th fast axis collimating mirror 120'. The N +1 th fast axis collimating lenses 120 ' are arranged in the fast axis direction and have a small height difference, the N +1 th fast axis collimating lenses 120 ' are also arranged in sequence in the slow axis direction, and the N +1 th slow axis collimating lenses 130 ' are arranged in sequence in the slow axis direction. In the N +1 st collimating mirror, the N +1 st fast axis collimating mirror 120 ' is located between the N +1 st semiconductor laser emitting tube 110 ' and the N +1 th slow axis collimating mirror 130 '. The (N +1) th fast axis collimating lens 120 ' is adapted to collimate the laser beam output from the (N +1) th semiconductor laser emitting tube 110 ' in the fast axis direction, and the (N +1) th slow axis collimating lens 130 ' is adapted to collimate the laser beam in the slow axis direction. After the N + 1-th fast axis collimating lens 120 'collimates the laser beam in the fast axis, the N + 1-th slow axis collimating lens 130' collimates the laser beam in the slow axis direction. The number of the (N +1) th slow-axis collimating mirrors 130 'is the same as that of the (N +1) th semiconductor laser emitting tubes 110',the number of the N +1 th fast axis collimating mirrors 120 'is the same as that of the N +1 th semiconductor laser emitting tubes 110'. An angle of 45 degrees is formed between the normal direction of the N +145 degree reflecting mirror 140 'and the incident direction of the laser light incident on the N +145 degree reflecting mirror 140', the N +145 degree reflecting mirror 140 'is suitable for reflecting the laser light collimated by the N +1 slow axis collimating mirror 130' and the N +1 fast axis collimating mirror 120 'toward the volume grating 22, and the N +145 degree reflecting mirror 140' deflects the optical path of the laser light by 90 degrees. The number of N +145 reflecting mirrors 140 'is the same as the number of N +1 slow axis collimating mirrors 130'. The N +145 degree reflectors 140 ' have height difference in the fast axis direction, so that the N +145 degree reflectors 140 ' do not block the laser beams reflected by the N +145 degree reflectors on the light path, and each laser beam is reflected by the corresponding N +145 degree reflector 140 ' and then enters the N +1 focusing and coupling mirror unit. An N +1 th semiconductor laser emitting tube 110 'corresponds to an N +1 th fast axis collimator 120', an N +1 th slow axis collimator 130 'and an N +145 degree reflector 140'.

Referring to fig. 4, the (N +1) th focusing and coupling mirror unit 156 is adapted to focus the collimated laser light and couple the collimated laser light to the (N +1) th energy transmission fiber C_N+1The N +1 th focusing coupling mirror unit 156 focuses the collimated laser beam to make the size of the focused spot smaller than the N +1 th energy transmission fiber C_N+1So that the laser beam can pass through the N +1 th energy-transmitting fiber C_N+1And (5) transmitting. The (N +1) th focusing coupling mirror 156 unit comprises an (N +1) th fast axis focusing coupling mirror and an (N +1) th slow axis focusing coupling mirror, wherein the (N +1) th fast axis focusing coupling mirror is positioned between the (N + 145) th reflecting mirrors and the (N +1) th slow axis focusing coupling mirror.

The body grating 22 arranged in the body grating locking module S is used as a resonance feedback structure of a plurality of N +1 semiconductor laser luminous tubes. The bulk grating locking module S uses the bulk grating 22 for wavelength locking. In the bulk grating locking module S, the bulk grating 22 partially transmits laser to enter the N +1 energy transmission optical fiber C_N+1The body grating 22 can reflect the light beam with a specific wavelength, so the light beam with the specific wavelength is reflected by the body grating 22 to enter the N +1 semiconductor laser emitting tube 110 ', and a competition mode is formed inside the N +1 semiconductor laser emitting tube 110', thereby realizing wavelength locking and spectrumNarrowing, and because of the presence of the optical fiber combiner in this embodiment, mutual wavelength locking is achieved between the respective N +1 th semiconductor laser emitting tubes 110'. The volume of the volume grating 22 is small, and miniaturization of the entire wavelength-locked semiconductor laser system can be achieved.

The optical fiber combiner 10 includes first to N +1 th input optical fibers and an output optical fiber 101; the kth energy transmission optical fiber is connected with the kth input optical fiber, and the N +1 th energy transmission optical fiber is connected with the N +1 th input optical fiber. The optical fiber combiner 10 is an (N +1) × 1 optical fiber combiner, that is, the optical fiber combiner has (N +1) input channels and 1 output channel. Secondly, the laser beam combining is carried out by using the optical fiber beam combiner, and the output power of the output optical fiber is increased by N +1 times.

The laser beam transmitted by the body grating enters the N +1 energy transfer optical fiber and the optical fiber beam combiner 10 in sequence in the state that the body grating 22 locks a plurality of N +1 semiconductor laser luminous tubes, the laser beam is reflected back to a part of laser by a partial reflection structure when reaching the output end surface of the output optical fiber, the reflected laser sequentially returns to the output optical fiber and the input optical fiber (from the first input optical fiber to the N +1 th input optical fiber), the reflected laser is divided into a plurality of reflected laser beam splitting by the first input optical fiber to the N +1 th input optical fiber, the plurality of reflected laser beam splitting respectively and correspondingly enters the first energy transmission optical fiber to the N +1 th energy transmission optical fiber, and then enters the first optical fiber coupling module to the N optical fiber coupling module and the bulk grating locking module, and the reflected laser beam entering the kth optical fiber coupling module is split to lock the kth semiconductor laser luminous tube in the kth optical fiber coupling module. Secondly, for any kth optical fiber coupling module from the first optical fiber coupling module to the Nth optical fiber coupling module, a laser beam output by the kth optical fiber coupling module sequentially passes through a kth energy transfer optical fiber and an optical fiber combiner, the laser beam output by the kth optical fiber coupling module is reflected to a part of laser by a partial reflection structure when reaching the output end face of an output optical fiber, the reflected laser sequentially returns to the output optical fiber and the optical fiber combiner 10, and is also divided into (N +1) paths of reflected laser beam splitting by a first input optical fiber to an N +1 th input optical fiber, the reflected laser beam splitting respectively enters a first energy transfer optical fiber to an N +1 th energy transfer optical fiber, wherein the reflected laser from the first energy transfer optical fiber to the N +1 th energy transfer optical fiber respectively returns to the first optical fiber coupling module to the Nth optical fiber coupling module, and the reflected laser from the N +1 th energy transfer optical fiber returns to the bulk grating locking module, therefore, for the first fiber coupling module to the Nth fiber coupling module and the bulk grating locking module, feedback light received by each module is light emitted by the module and light from the rest N modules, so that the modules are interlocked. The body grating locking module adopts the body grating to lock the wavelength, so that the locking state of the body grating locking module is not interfered by reflected light of a partial reflection structure, the locking of the body grating locking module on the first optical fiber coupling module to the Nth optical fiber coupling module is realized, the locking wavelength of the first optical fiber coupling module to the Nth optical fiber coupling module is completely consistent with the locking wavelength of the body grating locking module, and the spectrum of the output light beam of the wavelength locking semiconductor laser system is narrowed.

The volume grating locking module further comprises: a central wavelength detection unit (not shown) adapted to detect a central wavelength shift degree of the laser light emitted from the N +1 th semiconductor laser emitting tube 110'; a temperature control unit (not shown) adapted to perform temperature compensation on the volume grating 22 according to the degree of central wavelength shift to reduce the central wavelength shift of the laser.

The temperature control module comprises a semiconductor refrigeration piece and a feedback control unit (not shown), the semiconductor refrigeration piece is in contact with the body grating 22, the semiconductor refrigeration piece is suitable for refrigerating the body grating 22, the semiconductor refrigeration piece is also suitable for heating the body grating 22, and the feedback control unit is suitable for adjusting the refrigerating degree and the heating degree of the semiconductor refrigeration piece according to the central wavelength deviation degree of the laser detected by the central wavelength detection module.

When the central wavelength detection module detects that the central wavelength of the laser deviates to the short wave direction, the feedback control unit is suitable for controlling the semiconductor refrigeration piece to heat the volume grating 22; when the central wavelength detection module detects that the central wavelength of the laser deviates towards the long-wave direction, the feedback control unit is suitable for controlling the semiconductor refrigerating sheet to refrigerate the volume grating 22.

The central wavelength drift of the bulk grating locking module is controlled. When the central wavelength drift of the bulk grating locking module is controlled, the locking central wavelengths of all the first fiber coupling modules to the Nth fiber coupling module are consistent and synchronously changed, so that the widening of the final combined output light spectrum caused by the fact that different modules are locked at different central wavelengths is avoided, namely the whole system can realize the adjustability and controllability of the locking central wavelength under the condition that the spectrum width is consistent with the spectrum width of a single bulk grating locking module.

It should be understood that the above examples are only for clarity of illustration and are not intended to limit the embodiments. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. And obvious variations or modifications therefrom are within the scope of the invention.