阅读说明：本技术 双波长激光输出装置及方法、半导体激光器 (Dual-wavelength laser output device and method, and semiconductor laser ) 是由 郑婉华 鲁玉环 张伟桥 周旭彦 渠红伟 于 2021-09-23 设计创作，主要内容包括：本公开提供了一种双波长激光输出装置,应用于光学技术领域,包括：光源模块,用于输出不同偏振态的偏振光；反射光栅,用于将偏振光中第一指定波长的光束进行一级衍射得到第一指定波长的衍射光,以及,对偏振光进行零级衍射得到零级衍射光；全反射镜,用于将第一指定波长的衍射光反射到反射光栅上；体布拉格光栅,用于对零级衍射光中的第二指定波长的光束进行衍射,得到第二指定波长的衍射光；反射光栅,还用于对第一指定波长的衍射光进行一级衍射至光源模块,以及,对第二指定波长的衍射光进行零级衍射至光源模块。本申请还公开了一种双波长激光输出装置方法、半导体激光器,可输出等强度的双波长激光。(The utility model provides a dual wavelength laser output device is applied to optics technical field, includes: the light source module is used for outputting polarized light in different polarization states; the reflection grating is used for performing first-order diffraction on a light beam with a first specified wavelength in the polarized light to obtain diffracted light with the first specified wavelength and performing zero-order diffraction on the polarized light to obtain zero-order diffracted light; a total reflection mirror for reflecting the diffracted light of the first prescribed wavelength onto the reflection grating; the volume Bragg grating is used for diffracting the light beam with the second specified wavelength in the zero-order diffracted light to obtain the diffracted light with the second specified wavelength; the reflection grating is also used for performing first-order diffraction on the diffracted light with the first specified wavelength to the light source module and performing zero-order diffraction on the diffracted light with the second specified wavelength to the light source module. The application also discloses a dual-wavelength laser output device and method, and a semiconductor laser capable of outputting dual-wavelength laser with equal intensity.)

1. A dual wavelength laser output apparatus, comprising:

the light source module is used for outputting polarized light in different polarization states;

the reflection grating is used for receiving the polarized light along a first direction, performing first-order diffraction on a light beam with a first specified wavelength in the polarized light to obtain diffracted light with the first specified wavelength, and performing zero-order diffraction on the polarized light to obtain zero-order diffracted light;

a total reflection mirror for receiving the diffracted light of the first specified wavelength from a second direction and reflecting the diffracted light of the first specified wavelength onto the reflection grating in a direction opposite to the second direction;

the volume Bragg grating is used for receiving the zero-order diffracted light along a third direction and diffracting a light beam with a second specified wavelength in the zero-order diffracted light to obtain diffracted light with the second specified wavelength;

the reflection grating is further configured to receive the diffracted light with the first specified wavelength in the opposite direction of the second direction and the diffracted light with the second specified wavelength in the opposite direction of the third direction, perform first-order diffraction on the diffracted light with the first specified wavelength in the opposite direction of the first direction to the light source module, and perform zero-order diffraction on the diffracted light with the second specified wavelength in the opposite direction of the first direction to the light source module.

2. The dual wavelength laser output apparatus as claimed in claim 1, wherein the light source module includes:

the semiconductor laser gain chip is used for emitting laser;

the collimation module is used for receiving the laser and collimating the divergence angle of the laser;

and the polarization state adjusting module is used for receiving the collimated laser and adjusting the polarization state of the collimated laser to be a target polarization state to obtain the polarized light.

3. The dual wavelength laser output device of claim 2, wherein the collimating module comprises:

the fast axis collimating mirror is used for receiving the laser and collimating the divergence angle of the laser in the fast axis direction to obtain first laser;

and the slow axis collimating mirror is used for receiving the first laser and collimating the divergence angle of the light beam in the slow axis direction to obtain second laser, and the second laser comprises the collimated laser.

4. The dual-wavelength laser output device according to claim 2, wherein an emission end face of the semiconductor laser gain chip is coated with an antireflection film;

and the opposite end surfaces of the emitting ends of the semiconductor laser gain chips are plated with high-reflection films.

5. The dual wavelength laser output device according to claim 1, wherein the reflection grating is a blazed grating;

the blazed angle of the blazed grating is different along with the difference of the incident angle of the light beam when the incident light is incident on the reflection grating, and the difference between the incident angle and the blazed angle is less than 3 degrees.

6. The dual wavelength laser output apparatus as claimed in claim 1, wherein the total reflection mirror is rotatable within a preset angle range.

7. The dual wavelength laser output device of claim 2, wherein the polarization state adjustment module comprises a zero-order half waveplate.

8. A semiconductor laser characterized by comprising the dual wavelength laser output device as claimed in any one of claims 1 to 7.

9. A control method applied to the dual wavelength laser output apparatus of any one of claims 1 to 7, comprising:

controlling the light source module to output polarized light;

the total reflection mirror is controlled to rotate to change the angle at which diffracted light of the first specified wavelength is reflected back to the reflection grating.

10. The control method of claim 9, wherein when the light source module comprises a zero-order half waveplate, the method further comprises:

the rotation of the zero-order half waveplate is controlled to change the polarization state of the polarized light.

Technical Field

The application relates to the technical field of optics, in particular to a dual-wavelength laser output device and method and a semiconductor laser.

Background

The dual-wavelength laser is a laser beam which can simultaneously emit two wavelengths, and can be widely applied to the fields of dual-wavelength interference imaging, optical switches, terahertz pumping sources, optical sensing and the like. For example, a dual-wavelength tunable pumping source is used for outputting two laser wavelengths with similar wavelengths and matched with each other, the dual-wavelength laser interacts with a nonlinear medium with a good second-order nonlinear coefficient to generate a difference frequency, and finally terahertz radiation is obtained.

The current methods for realizing dual-wavelength laser output mainly include two types: 1. a monolithic integrated semiconductor laser realizes stable dual wavelengths through a complex epitaxial design or a complex process flow, has a high longitudinal mode rejection ratio and a small volume, but has a small wavelength difference tunable range between the dual wavelengths and low output power. 2. Based on semiconductor lasers fed back by different external cavities, a specific spectrum mode is selected by a diffractive optical element and fed back to be injected into a gain area of the semiconductor laser, and the currently known structures comprise a double Littrow external cavity, a double Littmann structure, a double VBG external cavity and the like. The dual-wavelength external cavity structure laser output generally has the characteristic of high power, but the advantages and the disadvantages of different external cavity structures are also obvious. For a double-VBG external cavity structure, the side mode rejection ratio of output laser is high, but the wavelength difference between the two wavelengths cannot be tuned; for external cavity structures such as a double Littrow external cavity structure using a surface grating, the tunable range is wide, but the side mode suppression ratio of the structure is not high; for the composite cavity structure using VBG and surface grating simultaneously, because the diffraction efficiency of the surface grating to different wavelengths in the same polarization state is not high, the output intensity of the dual wavelengths is different.

Disclosure of Invention

The main purpose of the present application is to provide a dual-wavelength laser output device and method, and a semiconductor laser, which have high power, easy tuning, high longitudinal mode rejection ratio, and dual-wavelength equal-intensity output.

In order to achieve the above object, a first aspect of the embodiments of the present application provides a dual-wavelength laser output apparatus, including:

the light source module is used for outputting polarized light in different polarization states;

the reflection grating is used for receiving the polarized light along a first direction, performing first-order diffraction on a light beam with a first specified wavelength in the polarized light to obtain diffracted light with the first specified wavelength, and performing zero-order diffraction on the polarized light to obtain zero-order diffracted light;

a total reflection mirror for receiving the diffracted light of the first specified wavelength from a second direction and reflecting the diffracted light of the first specified wavelength onto the reflection grating in a direction opposite to the second direction;

the volume Bragg grating is used for receiving the zero-order diffracted light along a third direction and diffracting a light beam with a second specified wavelength in the zero-order diffracted light to obtain diffracted light with the second specified wavelength;

the reflection grating is further configured to receive the diffracted light with the first specified wavelength in the opposite direction of the second direction and the diffracted light with the second specified wavelength in the opposite direction of the third direction, perform first-order diffraction on the diffracted light with the first specified wavelength in the opposite direction of the first direction to the light source module, and perform zero-order diffraction on the diffracted light with the second specified wavelength in the opposite direction of the first direction to the light source module.

In an embodiment of the present disclosure, the light source module includes:

the semiconductor laser gain chip is used for emitting laser;

the collimation module is used for receiving the laser and collimating the divergence angle of the laser;

and the polarization state adjusting module is used for receiving the collimated laser and adjusting the polarization state of the collimated laser to be a target polarization state to obtain the polarized light.

In an embodiment of the present disclosure, the collimating module includes:

the fast axis collimating mirror is used for receiving the laser and collimating the divergence angle of the laser in the fast axis direction to obtain first laser;

and the slow axis collimating mirror is used for receiving the first laser and collimating the divergence angle of the light beam in the slow axis direction to obtain second laser, and the second laser comprises the collimated laser.

In one embodiment of the present disclosure, an anti-reflection film is plated on the emission end face of the semiconductor laser gain chip;

and the opposite end surfaces of the emitting ends of the semiconductor laser gain chips are plated with high-reflection films.

In an embodiment of the present disclosure, the reflective grating is a blazed grating;

the blazed angle of the blazed grating is different along with the difference of the incident angle of the light beam when the incident light is incident on the reflection grating, and the difference between the incident angle and the blazed angle is less than 3 degrees.

In an embodiment of the present disclosure, the total reflection mirror is rotatable within a predetermined angle range.

In an embodiment of the present disclosure, the polarization state adjustment module includes a zero-order half waveplate.

A second aspect of the embodiments of the present application provides a semiconductor laser including the dual-wavelength laser output device according to the first aspect.

A third aspect of the embodiments of the present application provides a control method, which is applied to the dual-wavelength laser output apparatus in the first aspect, and includes:

controlling the light source module to output polarized light;

the total reflection mirror is controlled to rotate to change the angle at which diffracted light of the first specified wavelength is reflected back to the reflection grating.

In an embodiment of the present disclosure, when the light source module includes a zero-order half waveplate, the method further includes:

the rotation of the zero-order half waveplate is controlled to change the polarization state of the polarized light.

According to the embodiment of the disclosure, the dual-wavelength laser output device comprises a reflection grating and a volume bragg grating, wherein the reflection grating can select the light beam with the first specified wavelength to perform first-order diffraction to obtain the diffracted light with the first specified wavelength, the volume bragg grating can select the light beam with the second specified wavelength to perform diffraction to obtain the diffracted light with the second specified wavelength, so that the selection of a spectrum is completed, and the dual-wavelength laser output is realized. The tunable range of the reflection grating is wide, the mode can be continuously tuned, the spectral mode locking characteristic of the volume Bragg grating is excellent, the structure that only the reflection grating or the volume Bragg grating is used as a diffraction element is compared, and the device has the advantages of wide tuning range and high longitudinal mode rejection ratio by simultaneously adopting two diffraction elements.

Drawings

In order to more clearly illustrate the embodiments of the present application 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, it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

Fig. 1 is a diagram illustrating a dual-wavelength laser output apparatus according to an embodiment of the present disclosure;

fig. 2 is a diagram illustrating a dual-wavelength laser output apparatus according to an embodiment of the present disclosure;

fig. 3 is an output spectrum curve of a conventional semiconductor laser provided in an embodiment of the present application;

FIG. 4 is a laser output spectrum plot of a dual wavelength laser output apparatus provided herein;

fig. 5 is a corresponding dual-wavelength power curve diagram of the dual-wavelength laser output device according to the embodiment of the present application;

fig. 6 is a flowchart illustrating a control method according to an embodiment of the present application.

Detailed Description

In order to make the purpose, features and advantages of the present application more obvious and understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, fig. 1 is a diagram of a dual-wavelength laser output device according to an embodiment of the present disclosure, which can output dual-wavelength laser with equal intensity, and the dual-wavelength laser output device includes a light source module 10, a reflective grating 5, a total reflector 6, and a volume bragg grating 7.

A light source module 10 for outputting polarized light of different polarization states; the reflection grating 5 is used for receiving the polarized light along a first direction, performing first-order diffraction on a light beam with a first specified wavelength in the polarized light to obtain diffracted light with the first specified wavelength, and performing zero-order diffraction on the polarized light to obtain zero-order diffracted light; a total reflection mirror 6 for receiving the diffracted light of the first specified wavelength from the second direction and reflecting the diffracted light of the first specified wavelength onto the reflection grating 5 in the opposite direction of the second direction; the volume Bragg grating 7 is used for receiving the zero-order diffracted light along a third direction and diffracting a light beam with a second specified wavelength in the zero-order diffracted light to obtain diffracted light with the second specified wavelength; the reflection grating 5 is further configured to receive the diffracted light with the first specified wavelength in the opposite direction of the second direction and the diffracted light with the second specified wavelength in the opposite direction of the third direction, perform first-order diffraction on the diffracted light with the first specified wavelength in the opposite direction of the first direction to the light source module 10, and perform zero-order diffraction on the diffracted light with the second specified wavelength in the opposite direction of the first direction to the light source module 10.

In an embodiment of the present disclosure, a littrow angle is formed between the first direction and a normal of the reflection grating 5, that is, a light beam, which is emitted by the light source module 10 and enters the reflection grating 5, and a certain included angle is formed between the normal of the reflection grating 5 and the light beam, which satisfies the littrow angle of the reflection grating 5, so that the reflection grating 5 can diffract the light beam with the first specified wavelength at one time, and the total reflection mirror 6 can feed back the light beam with the first specified wavelength to the reflection grating 5 according to an original light path, thereby outputting the diffracted light with the first specified wavelength.

In the present disclosure, the second direction is perpendicular to the volume bragg grating 7, that is, the zero-order diffracted light from the reflection grating 5 to the volume bragg grating 7 is perpendicular to the volume bragg grating 7, so that the volume bragg grating 7 can feed back the diffracted light with the second specified wavelength to the reflection grating 5 according to the original optical path, thereby outputting the diffracted light with the second specified wavelength.

According to the embodiment of the disclosure, the dual-wavelength laser output device includes the reflection grating 5 and the volume bragg grating 7, the reflection grating 5 can select the light beam with the first specified wavelength to perform first-order diffraction to obtain diffracted light with the first specified wavelength, the volume bragg grating 7 can select the light beam with the second specified wavelength to perform diffraction to obtain diffracted light with the second specified wavelength, so as to complete selection of a spectrum and realize dual-wavelength laser output. The tunable range of the reflection grating 5 is wide, the mode can be continuously tuned, the spectral mode locking characteristic of the volume Bragg grating 7 is excellent, compared with a structure which only uses the reflection grating 5 or the volume Bragg grating 7 as a diffraction element, and the device can have a wide tuning range and a high longitudinal mode rejection ratio by simultaneously adopting two diffraction elements.

Referring to fig. 2, fig. 2 is a dual-wavelength laser output device according to an embodiment of the present disclosure, the dual-wavelength laser output device includes a light source module 10, a reflective grating 5, a total reflector 6, and a volume bragg grating 7 shown in fig. 1, where the light source module 10 includes a semiconductor laser gain chip 1, a collimating module, and a polarization state adjusting module 4.

The semiconductor laser gain chip 1 is used for emitting laser;

the collimation module is used for receiving the laser and collimating the divergence angle of the laser;

and the polarization state adjusting module 4 is configured to receive the collimated laser, and adjust the polarization state of the collimated laser to a target polarization state to obtain the polarized light.

In this disclosure, when the light source module 10 includes the semiconductor laser gain chip 1, the collimating module and the polarization state adjusting module 4, the diffracted light with the first specified wavelength, which is diffracted to the light source module 10 in the first direction in the first order, and the diffracted light with the second specified wavelength, which is diffracted to the light source module 10 in the first direction in the second order, will sequentially pass through the polarization state adjusting module 4, the collimating module and the semiconductor laser gain chip 1 to perform the gain mode, so as to generate the dual-wavelength laser.

In an embodiment of the present disclosure, the semiconductor gain chip is a common single semiconductor laser gain chip 1, and compared with a monolithic integrated dual wavelength laser, a high power output can be realized.

In one embodiment of the present disclosure, the emission end face of the semiconductor laser gain chip 1 is plated with an anti-reflection film; and/or, the opposite end surface of the emitting end of the semiconductor laser gain chip 1 is plated with a high-reflection film so as to output high-power laser.

In an embodiment of the present disclosure, the collimating module includes a fast axis collimating mirror 2 and a slow axis collimating mirror 3, the position of the fast axis collimating mirror 2 corresponds to the position of the semiconductor laser gain chip 1, the position of the slow axis collimating mirror 3 corresponds to the position of the fast axis collimating mirror 2, and the position of the zero-order half-wave plate corresponds to the position of the slow axis collimating mirror 3.

The fast axis collimating mirror 2 is used for receiving the laser and collimating the divergence angle of the laser in the fast axis direction to obtain first laser; and the slow axis collimating mirror 3 is used for receiving the first laser and collimating the divergence angle of the light beam in the slow axis direction to obtain second laser, and the second laser comprises the collimated laser.

In an embodiment of the present disclosure, antireflection films are coated on two sides of the fast axis collimating mirror 2, the slow axis collimating mirror 3, and the zero-order half-wave plate. The incident mirror surface and the emergent mirror surface of the fast axis collimating mirror 2, the slow axis collimating mirror 3 and the zero-order half-wave plate are coated with antireflection films.

In an embodiment of the present disclosure, the polarization state adjustment module 4 includes a zero-order half wave plate, and since the reflection grating 5 has diffraction efficiencies for different wavelengths and different polarizations, the polarization state of the output polarized light can be changed by rotating the half wave plate, so as to compensate for the change of the diffraction efficiencies of different wavelengths on the diffraction grating, and compared with other tunable dual-wavelength systems using the reflection grating 5, dual-wavelength equal-intensity output can be accurately achieved.

In an embodiment of the present disclosure, the reflection grating 5 is a blazed grating, a blazed angle of the blazed grating is different according to a difference between incident angles of light beams when the incident light is incident on the reflection grating 5, and a difference between the incident angle and the blazed angle is less than 3 degrees.

In an embodiment of the present disclosure, the total reflection mirror 6 is rotatable within a predetermined angle range, so as to achieve the purposes of changing the angle at which the diffracted light with the first specified wavelength is reflected back to the reflection grating 5, completing diffraction with different wavelengths, facilitating tuning, outputting tunable laser in a wider range, and the like. The preset angle range may be 0 to 0.5 °, or 0 to 1 °, etc., which is not limited by the present disclosure, and the above object may be achieved while ensuring that the diffracted light with the first specified wavelength is reflected to the reflection grating 5 in the opposite direction of the second direction.

Referring to fig. 3, 4 and 5, fig. 3 is an output spectrum curve of a conventional semiconductor laser provided in the present application; fig. 4 is a laser output spectrum curve of the dual-wavelength laser output device according to the embodiment of the present application. As shown in fig. 3 and 4, the semiconductor laser in fig. 3 is single-wavelength output, and the output laser of the dual-wavelength laser output device of the present embodiment in fig. 4 is dual-wavelength, so that it can be seen that the present embodiment can provide dual-wavelength laser output. Fig. 5 is a corresponding dual-wavelength power curve diagram of the dual-wavelength laser output device provided in the embodiment of the present application, so that it can be seen that the embodiment can provide equal-intensity output of dual-wavelength laser.

Referring to fig. 6, fig. 6 is a flowchart illustrating a control method according to an embodiment of the present application, where the method is applicable to the dual-wavelength laser output apparatus shown in fig. 1 or fig. 2, and the method mainly includes the following steps:

s601, controlling the light source module 10 to output polarized light;

s602, the total reflection mirror 6 is controlled to rotate to change the angle at which the diffracted light of the first specified wavelength is reflected back to the reflection grating 5.

In the present disclosure, the total reflection mirror 6 is rotatable within a predetermined angle range, so as to achieve the purposes of changing the angle at which the diffracted light with the first specified wavelength is reflected back to the reflection grating 5, completing diffraction with different wavelengths, facilitating tuning, outputting tunable laser with a wider range, and the like. The preset angle range may be 0 to 0.5 °, or 0 to 1 °, etc., which is not limited by the present disclosure, and the above object may be achieved while ensuring that the diffracted light with the first specified wavelength is reflected to the reflection grating 5 in the opposite direction of the second direction.

In one embodiment of the present disclosure, when the light source module 10 includes a zero-order half waveplate, the method further includes: the rotation of the zero-order half waveplate is controlled to change the polarization state of the polarized light.

In the disclosure, because the reflection grating 5 has diffraction efficiency for different wavelengths and different polarizations, the polarization state of the output polarized light can be changed by rotating the half-wave plate, so as to compensate the change of the diffraction efficiency of different wavelengths on the diffraction grating, and compared with other tunable dual-wavelength systems using the reflection grating 5, the dual-wavelength equal-intensity output can be accurately realized.

It should be noted that, for the sake of simplicity, the above-mentioned method embodiments are described as a series of acts or combinations, but those skilled in the art should understand that the present invention is not limited by the described order of acts, as some steps may be performed in other orders or simultaneously according to the present invention. Further, those skilled in the art will appreciate that the embodiments described in the specification are presently preferred and that no acts or modules are necessarily required of the invention.

In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.

In view of the above description of the dual-wavelength laser output device and method and the semiconductor laser provided by the present invention, those skilled in the art will appreciate that the embodiments and applications of the present invention can be modified, and the present disclosure should not be construed as limiting the present invention.