Antimonide single transverse mode external cavity laser

Abstract

The antimonide single transverse mode external cavity laser provided in the embodiment of the present application comprises at least an intrinsic cavity module, an external cavity feedback module and a laser output module; wherein the intrinsic cavity module comprises an antimonide gain chip having a substrate, an N-type antimonide layer, an active region, a P-type antimonide layer and an electrode stacked sequentially from bottom to top; the external cavity feedback module is arranged on the outer side of the front cavity surface of the antimonide gain chip, and the laser output module is arranged on the outer side of the rear cavity surface of the antimonide gain chip; the laser beam emitted from the front cavity surface of the antimonide gain chip is selected, filtered and diffracted by the wavelength tuning component, and then reflected to the front cavity surface side along the incident light path, and emitted from the rear cavity surface after being transmitted by the active region, and finally output in the form of a single transverse mode. The present application adopts an antimonide gain chip as a gain medium, expands the working wavelength of the laser to the mid-infrared band, improves the wavelength selectivity and tuning range, and well maintains the single-mode output characteristics.

Description

Technical Field

[0001] The present application relates to the field of optical communication technology, and in particular to an antimonide single transverse mode external cavity laser. Background Art

[0002] With the continuous development of fields such as optical communications, sensing technology and environmental monitoring, the demand for laser sources that can operate efficiently and stably in the mid-infrared band (2-4 microns) is also growing. The 2-4 micron band is the atmospheric window band, which is particularly important for the detection of gas molecules. Many important gases (such as carbon dioxide, water vapor, methane, etc.) have strong absorption lines in this wavelength range and can be used for high-precision detection and analysis. Traditionally, this band mainly relies on quantum cascade lasers and other types of solid-state lasers, but they are usually large in size, complex in manufacturing process, high in cost and difficult to integrate, and there are challenges in temperature stability and wavelength selectivity in some applications.

[0003] Traditional semiconductor lasers have limited tuning range, low output power, wide line width, and difficulty in achieving single transverse mode operation. These problems have hindered the wider application of semiconductor lasers to a certain extent and limited their adaptability and flexibility in applications. For high-resolution spectral measurements, narrow line width is crucial, but traditional lasers often find it difficult to balance narrow line width with wide tuning range. Summary of the invention

[0004] The present application provides an antimonide single transverse mode external cavity laser, which can solve the technical problems of traditional semiconductor lasers such as limited tuning range, low output power, wide line width, and difficulty in achieving single transverse mode operation.

[0005] In a first aspect, an embodiment of the present application provides an antimonide single transverse mode external cavity laser, comprising:

[0006] The intrinsic cavity module comprises an antimonide gain chip; the antimonide gain chip comprises a substrate, an N-type antimonide layer, an active region, a P-type antimonide layer and an electrode for connecting an external power supply, which are stacked in sequence from bottom to top; when a voltage is applied to the electrode, electrons are injected from the N-type antimonide layer into the active region, holes are injected from the P-type antimonide layer into the active region, and the electrons and holes are recombined and excited in the active region to generate a laser beam; the antimonide gain chip comprises a front cavity surface and a rear cavity surface which are arranged oppositely, and the laser beam is emitted through the front cavity surface;

[0007] An external cavity feedback module is arranged on the outer side of the front cavity surface of the antimonide gain chip; the external cavity feedback module at least includes a wavelength tuning component; the external cavity feedback module is used to receive the laser beam emitted through the front cavity surface of the antimonide gain chip, and perform frequency-selective filtering on the laser beam through the wavelength tuning component, and the laser beam after the frequency-selective filtering is reflected along the incident light path to the front cavity surface side of the antimonide gain chip after diffraction, and is emitted from the rear cavity surface of the antimonide gain chip after being transmitted by the active region;

[0008] The laser output module is arranged on the outer side of the back cavity surface of the antimonide gain chip, and is used to receive the diffracted laser beam emitted from the back cavity surface of the antimonide gain chip, and output it in a single transverse mode.

[0009] In some embodiments, the antimonide includes at least one of a binary antimonide, a multinary antimonide and an antimony-containing compound semiconductor material; the binary antimonide includes at least one of gallium antimonide and indium antimonide; the multinary antimonide includes at least one of aluminum gallium antimony, indium gallium antimony and aluminum gallium indium antimony; the antimony-containing compound semiconductor material includes at least one of antimony silver ore and antimony palladium ore.

[0010] In some embodiments, the front cavity surface of the antimonide gain chip is coated with an antireflection film, and the back cavity surface is coated with a reflection film.

[0011] In some embodiments, the transmittance of the antireflection film on the front cavity surface of the antimonide gain chip is greater than 99.5%; the reflectivity of the reflection film on the back cavity surface of the antimonide gain chip is greater than 99%.

[0012] In some embodiments, the external cavity feedback module also includes a collimating mirror arranged along the optical path; the collimating mirror is an aspheric lens, which is used to expand and collimate the incident laser light beam; the wavelength tuning component at least includes a blazed grating; the blazed grating and the back cavity surface of the antimonide gain chip form a resonant cavity, and the wavelength tuning of the diffracted laser light beam is achieved by rotating the angle of the blazed grating.

[0013] In some embodiments, the blazed grating is controlled to rotate by a rotation mechanism;

[0014] The rotating mechanism includes at least a rotating motor, a position sensor and a controller; the rotating motor is arranged at the edge of the blazing grating to drive the blazing grating to rotate; the position sensor is arranged between the rotating motor and the controller to measure the rotation angle of the blazing grating and feed it back to the controller; the controller is connected to the rotating motor to control the rotation direction of the blazing grating and adjust the rotation angle around the axis.

[0015] In some embodiments, the laser output module includes at least a single-mode optical fiber directly coupled to the antimonide gain chip.

[0016] In some embodiments, the light incident end face of the single-mode optical fiber has two symmetrically arranged inclined surfaces to form a wedge-shaped incident end face, and the wedge-shaped incident end face is processed into a fiber microlens.

[0017] In some embodiments, the angle of the wedge-shaped incident end face of the single-mode optical fiber is 60°-120°.

[0018] In some embodiments, the wedge-shaped incident end face of the single-mode optical fiber is coated with an anti-reflection film, and the transmittance of the anti-reflection film on the wedge-shaped incident end face of the single-mode optical fiber is greater than 99%.

[0019] The antimonide single transverse mode external cavity laser provided in the embodiment of the present application comprises at least an intrinsic cavity module, an external cavity feedback module and a laser output module; wherein the intrinsic cavity module comprises an antimonide gain chip having a substrate, an N-type antimonide layer, an active region, a P-type antimonide layer and an electrode for connecting an external power supply stacked in sequence from bottom to top; the external cavity feedback module is arranged on the outer side of the front cavity surface of the antimonide gain chip, and the laser output module is arranged on the outer side of the rear cavity surface of the antimonide gain chip; the laser beam emitted from the front cavity surface of the antimonide gain chip is selected, filtered and diffracted by a wavelength tuning component, and then reflected to the front cavity surface side along the incident light path, and emitted from the rear cavity surface after being transmitted by the active region, and finally output in the form of a single transverse mode.

[0020] This application uses an antimonide gain chip as the gain medium to extend the operating wavelength of the laser to the mid-infrared band, enhances the application flexibility of the laser, and greatly broadens its application scenarios; at the same time, the structure of the single transverse mode coupled external cavity grating improves the wavelength selectivity and tuning range, enhances the robustness of the system, and maintains the single-mode output characteristics well. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0022] Figure 1 A schematic diagram of the structure of an antimonide single transverse mode external cavity laser provided in one embodiment of the present application.

[0023] Figure 2 A schematic diagram of the structure of an antimonide gain chip provided in one embodiment of the present application.

[0024] Figure 3 A schematic diagram of the laser light path in an external cavity feedback module provided in one embodiment of the present application.

[0025] Figure 4A schematic diagram of the laser light path in an external cavity feedback module provided in one embodiment of the present application.

[0026] Figure 5 A schematic diagram of the structure of an antimonide single transverse mode external cavity laser provided in one embodiment of the present application.

[0027] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0028] The present application is further described in detail below by specific embodiments in conjunction with the accompanying drawings. Wherein similar elements in different embodiments adopt associated similar element numbers. In the following embodiments, many detailed descriptions are intended to enable the present application to be better understood. However, those skilled in the art can easily recognize that some of the features can be omitted in different situations, or can be replaced by other elements, materials, and methods. In some cases, some operations related to the present application are not shown or described in the specification, in order to avoid the core part of the present application being overwhelmed by too much description, and for those skilled in the art, it is not necessary to describe these related operations in detail, and they can fully understand the related operations based on the description in the specification and the general technical knowledge in the art.

[0029] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner to form various implementations. At the same time, the steps or actions in the method description can also be interchanged or adjusted in a manner that is obvious to those skilled in the art. Therefore, the various sequences in the specification and the drawings are only for the purpose of clearly describing a certain embodiment and are not meant to be a required sequence, unless otherwise specified that a certain sequence must be followed.

[0030] The terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable when appropriate, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are usually a class, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated before and after are in an "or" relationship. The "connection" and "connection" mentioned in this application, unless otherwise specified, include direct and indirect connections (connections).

[0031] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0032] Figure 1 This is a schematic diagram of the structure of an antimonide single transverse mode external cavity laser provided in one embodiment of the present application. Figure 1 As shown, the antimonide single transverse mode external cavity laser provided in this embodiment at least includes an intrinsic cavity module 110 , an external cavity feedback module 120 and a laser output module 130 .

[0033] In this embodiment, the intrinsic cavity module 110 serves as the core part of the laser. The intrinsic cavity module 110 is responsible for amplifying or oscillating the light in certain excited substances through the principle of stimulated radiation, so as to generate and amplify the laser. The external cavity feedback module 120 is connected to the intrinsic cavity module 110 and is responsible for providing a feedback signal to stabilize the output of the laser. It is possible to form a stable laser oscillation by precisely controlling the reflection and interference of the laser in the cavity, with high precision and tunability, and to adjust the laser frequency, line width and output power. The laser output module 130 is located at the end of the laser and is responsible for outputting the stable laser to the external environment. It usually includes an output mirror and a coupling system, with high coupling efficiency and output stability, and couples the laser from the cavity to an external optical fiber or free space.

[0034] Typically, the intrinsic cavity module 110 includes at least a gain chip, which, as an optical gain medium, is a key component in a laser and plays a vital role in the generation and amplification of lasers. In a laser, the gain chip amplifies the input optical signal through the stimulated emission process and generates a high-intensity laser output; in this process, the active region in the gain chip is a key part, which contains particles or quantum wells that can generate lasers.

[0035] In this embodiment, the intrinsic cavity module 110 includes at least an antimonide gain chip 1101, which has irreplaceable advantages in the mid-infrared band, especially in terms of direct luminescence efficiency, wavelength adaptability and high-temperature stability. It is significantly superior to conventional compound materials. Antimonide materials usually have a smaller bandgap width, and its bandgap width is 0.6-1.0eV, which makes electrons easier to be excited and stored, and can achieve high-performance 2-4 μm mid-infrared band laser amplification. By adjusting the antimonide alloy composition (such as InGaAsSb, AlGaAsSb), the bandgap and lattice constant can be continuously adjusted to match different wavelength requirements. At the same time, since antimonide has a higher carrier mobility, this means that under the same electric field strength, the carriers in the antimonide can move faster, enhance the carrier confinement ability, reduce the threshold current, increase the output power, and also reduce the overall energy consumption of the laser. Antimonide materials usually have good thermal stability and reliability, which enables the antimonide gain chip 1101 to maintain stable performance at high temperatures or in harsh environments.

[0036] Figure 2 This is a schematic diagram of the structure of an antimonide gain chip provided by an embodiment of the present application. Figure 2 As shown, in this embodiment, the antimonide gain chip 1101 is based on quantum well epitaxial layer growth technology, and has a substrate a, an N-type antimonide layer b, an active area c, a P-type antimonide layer d and an electrode e for connecting an external power supply stacked from bottom to top.

[0037] The function of substrate a is to provide physical support for the chip and is the basis for crystal growth, which is used to ensure the structural integrity and stability of the chip. The N-type antimonide layer b is located above the substrate a and is an electron donor, which contains more free electrons. The P-type antimonide layer d is located above the active region c and is a hole acceptor, which contains more holes. In the gain chip, the N-type antimonide layer b and the P-type antimonide layer d together form a PN junction, which provides the necessary energy band structure for the generation of lasers. The active region c is the key area for generating lasers in the gain chip. It is a quantum well structure. Here, through the process of population inversion and stimulated radiation, photons are amplified and form a laser beam. The material selection and structural design of the active region c have an important influence on the performance of the laser. The front and rear cavity surfaces of the active region c constitute a Fabry-Pérot resonant cavity. Usually, the front cavity surface is partially reflected (output laser), and the rear cavity surface is fully reflected to enhance light feedback. The top of the electrode e is connected to the P-type layer, and the bottom electrode is connected to the N-type layer through the substrate a, forming a current path for connecting the control power supply to provide the necessary current input for the gain chip. Through the electrode e, current can be injected into the active area c, thereby stimulating the recombination process of electrons and holes, and then generating lasers.

[0038] The working process of the antimonide gain chip 1101 is as follows: a voltage is applied to the electrode e through an external power supply, electrons are injected from the N-type antimonide layer b into the active region c, holes are injected from the P-type antimonide layer d into the active region c, electrons and holes recombine in the active region c, and some electrons are excited to a high energy level, forming a population inversion distribution; in the population inversion state, electrons in the active region c will transition from a high energy level to a low energy level when stimulated by photons or other forms, and release photons in the same state as the exciting photons, and the released photons are reflected multiple times in the optical resonant cavity, and further interact with the electrons in the gain medium, inducing more stimulated radiation, and the number of photons increases exponentially, forming a laser; the optical resonant cavity formed by the front and rear cavity surfaces of the active region c provides positive feedback for the photons, so that the photons are reflected multiple times in the cavity and amplified, and after reaching the threshold current, the laser is emitted from the front cavity surface (partial reflection surface) of the active region c.

[0039] In some embodiments, the antimonide includes at least one of a binary antimonide, a multinary antimonide and an antimony-containing compound semiconductor material; the binary antimonide includes at least one of gallium antimonide (GaSb) and indium antimonide (InSb); the multinary antimonide includes at least one of aluminum gallium antimony (AlGaSb), indium gallium antimony (InGaSb) and aluminum gallium indium antimony (AlGaInSb); the antimony-containing compound semiconductor material includes at least one of antimony silver ore (such as AgSbS2 or Ag3SbS3, etc.) and antimony palladium ore (referring to a compound containing antimony and palladium).

[0040] In some embodiments, the front cavity surface of the antimonide gain chip 1101 is coated with an antireflection film, and the back cavity surface is coated with a reflective film. In certain cases, the transmittance of the antimonide gain chip 1101's front cavity surface antimonide gain chip 1101's antimonide reflective film is greater than 99.5%; the reflectance of the reflective film on the back cavity surface of the antimonide gain chip 1101 is greater than 99%.

[0041] In any of the above embodiments, the external cavity feedback module 120 is disposed on the outer side of the front cavity surface of the antimonide gain chip 1101, and the external cavity feedback module 120 at least includes a beam expansion collimation component 1201 and a wavelength tuning component 1202. The long tuning component is used to select and adjust the wavelength of the laser beam. Through the tuning component, the laser beam of a specific wavelength can be filtered, thereby optimizing the output characteristics of the laser.

[0042] Figure 3 This is a schematic diagram of the laser light path in the external cavity feedback module provided in one embodiment of the present application. Figure 3As shown, in this embodiment, the beam expansion and collimation component 1201 in the external cavity feedback module 120 receives the laser beam emitted from the front cavity surface of the antimonide gain chip 1101, and performs frequency selective filtering on the laser beam through the wavelength tuning component 1202. After diffraction, the laser beam after frequency selective filtering is reflected along the incident light path to the front cavity surface side of the antimonide gain chip 1101, and is transmitted through the active region c and emitted from the rear cavity surface of the antimonide gain chip 1101.

[0043] Figure 4 This is a schematic diagram of the laser light path in a laser output module provided in one embodiment of the present application. Figure 4 As shown, the laser output module 130 is arranged on the outer side of the back cavity surface of the antimonide gain chip 1101. The laser output module 130 includes a single-mode optical fiber 1301, which is used to receive the diffracted laser beam emitted from the back cavity surface of the antimonide gain chip 1101 and output it in the form of a single transverse mode. Among them, the single transverse mode means that the intensity distribution of the laser beam on the cross section is a single and stable mode. The single transverse mode output ensures the stability and predictability of the laser beam. Therefore, one of the tasks of the laser output module 130 is to rearrange the diffracted laser beam into a single transverse mode to meet the needs of specific applications.

[0044] In summary, the antimonide single transverse mode external cavity laser provided in this embodiment at least includes an intrinsic cavity module, an external cavity feedback module and a laser output module; wherein the intrinsic cavity module includes an antimonide gain chip having a substrate, an N-type antimonide layer, an active region, a P-type antimonide layer and an electrode for connecting an external power supply stacked in sequence from bottom to top; the external cavity feedback module is arranged on the outer side of the front cavity surface of the antimonide gain chip, and after receiving the laser beam emitted through the front cavity surface of the antimonide gain chip, the laser beam is frequency-selected, filtered and diffracted through a wavelength tuning component, and after diffraction, the laser beam is reflected along the incident light path to the front cavity surface side of the antimonide gain chip, and is emitted from the rear cavity surface after being transmitted through the active region of the antimonide gain chip; the laser output module is arranged on the outer side of the rear cavity surface of the antimonide gain chip, and after receiving the diffracted laser beam emitted through the rear cavity surface of the antimonide gain chip, the laser beam is output in a single transverse mode form. This antimonide single-transverse mode external cavity laser uses an antimonide gain chip as the gain medium, which extends the operating wavelength of the laser to the mid-infrared band, enhances the application flexibility of the laser, and greatly broadens its application scenarios; at the same time, the structure of the single-transverse mode coupled external cavity grating improves the wavelength selectivity and tuning range, enhances the robustness of the system, and maintains the single-mode output characteristics well.

[0045] Figure 5 This is a schematic diagram of the structure of an antimonide single transverse mode external cavity laser provided in one embodiment of the present application. Figure 5As shown, the antimonide single transverse mode external cavity laser of this embodiment includes an intrinsic cavity module 110 , an external cavity feedback module 120 and a laser output module 130 .

[0046] The intrinsic cavity module 110 at least includes an antimonide gain chip 1101, which extends the working wavelength of the semiconductor laser to the mid-infrared band. The antimonide gain chip 1101 has a front cavity surface and a rear cavity surface that are relatively arranged, and the laser beam generated by the excitation in the active area c is emitted from its front cavity surface. The front cavity surface of the antimonide gain chip 1101 is coated with an antireflection film, and the rear cavity surface is coated with a reflective film.

[0047] In this embodiment, the external cavity feedback module 120 includes a beam expansion and collimation component 1201 and a wavelength tuning component 1202 arranged along the optical path. The beam expansion and collimation component 1201 includes a collimator. The collimator receives the laser beam emitted from the front cavity surface of the antimonide gain chip 1101, expands and collimates the laser beam, and then emits the laser beam. The laser beam transmitted by the collimator is incident on the wavelength tuning component 1202. The wavelength tuning component 1202 performs frequency selective filtering on the laser beam. After diffraction, the laser beam after frequency selective filtering is reflected along the incident optical path to the front cavity surface side of the antimonide gain chip 1101, and is transmitted by the active region c of the antimonide gain chip 1101 and then emitted from the rear cavity surface of the antimonide gain chip 1101.

[0048] In some embodiments, the collimating lens is an aspheric lens, and through its special curved surface design, the divergence angle of the laser beam is reduced, thereby obtaining a wider and more parallel beam. When selecting an aspheric lens for laser beam expansion and collimation, factors such as the wavelength of the laser beam, the divergence angle, the diameter of the required collimated beam, and the focal length of the lens need to be considered. Assuming that the divergence angle of the light source is θ and the required beam diameter after collimation is Φ, the focal length of the aspheric lens suitable for this system can be calculated. Aspheric lenses can provide better beam quality and reduce the influence of aberrations such as spherical aberration. Compared with traditional spherical lenses, aspheric lenses usually have higher efficiency and better performance in laser beam expansion and collimation.

[0049] In some embodiments, the wavelength tuning component 1202 includes at least a blazed grating; the blazed grating and the back cavity surface of the antimonide gain chip 1101 form a resonant cavity, and the wavelength tuning of the diffracted laser beam is achieved by rotating the angle of the blazed grating. A blazed grating is an optical element manufactured using the principles of interference and diffraction of light. When the incident laser is irradiated onto the surface of the grating, the grating causes the light wave to diffract, producing a series of alternating light and dark diffraction fringes, the position and intensity of these diffraction fringes are related to the wavelength and incident angle of the incident light. By adjusting the parameters of the grating, the wavelength and incident angle of the incident light can be selected and analyzed. In a laser, a blazed grating can be used to select and tune the output wavelength of the laser. By adjusting the angle of the grating, the wavelength of the light fed back to the laser can be changed, thereby achieving monochromatic laser output.

[0050] The tuning principle of the blazed grating is based on the grating formula, i.e., d(sinθ+sinφ)=mλ, where d is the grating constant, θ is the incident angle, φ is the diffraction angle, m is the diffraction order, and λ is the wavelength. Rotating the blazed grating can change the incident angle θ, thereby selecting different wavelengths λ to achieve tuning.

[0051] In some embodiments, the rotation control of the blazed grating is achieved by a rotating mechanism, wherein the rotating mechanism at least includes a rotating motor, a position sensor and a controller; the rotating motor is arranged at the edge of the blazed grating to drive the blazed grating to rotate; the position sensor is arranged between the rotating motor and the controller to measure the rotation angle of the blazed grating and feed it back to the controller; the controller is connected to the rotating motor to control the rotation direction of the blazed grating and adjust the rotation angle around the axis.

[0052] like Figure 5 As shown, the laser output module 130 of this embodiment includes at least a single-mode optical fiber 1301, which is directly coupled to the antimonide gain chip 1101, and can effectively avoid the mode dispersion problem in the multi-mode optical fiber, thereby improving the efficiency and stability of laser transmission, ensuring that the output laser is transmitted in the optical fiber and also has good single-mode characteristics. The single-mode optical fiber 1301 has the advantages of low loss, low dispersion, high bandwidth, etc., and is suitable for long-distance, high-speed signal transmission.

[0053] In some embodiments, the light incident end face of the single-mode optical fiber 1301 has two symmetrically arranged inclined surfaces to form a wedge-shaped incident end face, and the wedge-shaped incident end face is processed into an optical fiber microlens. Making the incident section of the single-mode optical fiber 1301 into an inclined surface can increase the coupling tolerance of the optical fiber, help reduce the reflection of light at the end face of the optical fiber, reduce reflection loss, and thus improve the transmission efficiency of light. The optical fiber end face is processed into a lens-like shape, which has the function of changing the optical path or mode conversion, and can focus or diverge the incident light, thereby realizing the precise control and transmission of the optical signal. Through precise design and manufacturing, efficient transmission and reception of optical signals can be achieved, and the coupling efficiency between optical fibers and other optical elements can be improved. The inclined surface structure can also adjust the mode distribution of optical signals, reduce return loss, reduce crosstalk between adjacent channels, optimize transmission quality, and ensure stable transmission of optical signals in optical fibers.

[0054] In some embodiments, the angle of the wedge-shaped incident end face of the single-mode optical fiber 1301 is 60°-120°. By adjusting the wedge angle, the incident angle of the light on the optical fiber end face can be changed, thereby affecting the intensity and direction of the reflected light. Generally speaking, a larger wedge angle can more effectively reduce the intensity of the reflected light, but it may also bring other performance impacts, such as a reduction in coupling efficiency or a change in the optical signal mode. According to specific application requirements, by selecting an appropriate wedge angle, the single-mode optical fiber 1301 can maintain a high coupling efficiency or reduce the intensity of the reflected light. For example, in some application scenarios, a smaller wedge angle may be required to maintain a high coupling efficiency; in other scenarios, a larger wedge angle may be required to more effectively reduce the intensity of the reflected light.

[0055] In some embodiments, the wedge-shaped incident end face of the single-mode optical fiber 1301 is coated with an anti-reflection film, and the transmittance of the anti-reflection film on the wedge-shaped incident end face of the single-mode optical fiber 1301 is greater than 99%, so as to reduce the intensity of reflected light, increase the intensity of transmitted light, and further improve the transmission efficiency of optical signals.

[0056] The antimonide single transverse mode external cavity laser provided in this embodiment extends the working wavelength of the laser to the mid-infrared band by selecting the antimonide gain chip as the gain medium, thereby enhancing the application flexibility of the laser and greatly broadening its application scenarios; the blazed grating is selected as the extracavity frequency selection element to realize the structure of the antimonide single transverse mode coupled external cavity grating, improve the wavelength selectivity and tuning range, enhance the robustness of the system, and well maintain the single-mode output characteristics. Based on the back-cavity Littrow structure, the external grating feedback mechanism is used to rotate the blazed grating angle to achieve a wide range of wavelength tuning while maintaining good single-mode output characteristics. Direct coupling of microlens fiber with laser light source has many advantages such as simple and compact structure, easy alignment with semiconductor laser chip, simple manufacturing, and low production cost. The lens shape of the wedge-shaped fiber can well match the light field mode of the elliptical spot of the semiconductor laser. The two wedge surfaces of the wedge-shaped fiber lens correspond to the direction with a larger divergence angle of the semiconductor laser, which can increase the coupling efficiency of the fiber. The coupling efficiency value between the wedge-shaped microlens fiber and the semiconductor chip can reach more than 85%.

[0057] Therefore, the antimonide single transverse mode external cavity laser provided in this embodiment has the advantages of narrow line width, easy wavelength tuning, stable performance, good beam quality, and easy integration.

[0058] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the inspiration of the present application, ordinary technicians in the field can make several simple deductions, deformations or substitutions based on the ideas of the present application without departing from the scope of protection of the purpose of the present application and the claims. All of these are within the protection of the present application.

Claims

1. An antimonide single transverse mode external cavity laser, characterized in that: include: An intrinsic cavity module, including an antimonide gain chip; The antimonide gain chip comprises a substrate, an N-type antimonide layer, an active region, a P-type antimonide layer and an electrode for connecting an external power source, which are stacked in sequence from bottom to top; when a voltage is applied to the electrode, electrons are injected from the N-type antimonide layer into the active region, and holes are injected from the P-type antimonide layer into the active region, and the electrons and holes are recombined and excited in the active region to generate a laser beam; The antimonide gain chip has a front cavity surface and a rear cavity surface that are arranged opposite to each other, and the laser beam is emitted through the front cavity surface; An external cavity feedback module is arranged on the outer side of the front cavity surface of the antimonide gain chip; the external cavity feedback module at least includes a wavelength tuning component; the external cavity feedback module is used to receive the laser beam emitted through the front cavity surface of the antimonide gain chip, and perform frequency-selective filtering on the laser beam through the wavelength tuning component, and the laser beam after the frequency-selective filtering is reflected along the incident light path to the front cavity surface side of the antimonide gain chip after diffraction, and is emitted from the rear cavity surface of the antimonide gain chip after being transmitted by the active region; Wherein, the wavelength tuning component at least includes a blazed grating; the blazed grating and the back cavity surface of the antimonide gain chip form a resonant cavity, and the wavelength tuning of the diffracted laser beam is achieved by rotating the rotation angle of the blazed grating; The laser output module is arranged on the outer side of the back cavity surface of the antimonide gain chip, and is used to receive the diffracted laser beam emitted from the back cavity surface of the antimonide gain chip, and output it in a single transverse mode.

2. The antimonide single transverse mode external cavity laser according to claim 1, characterized in that: The antimonide includes at least one of a binary antimonide, a multinary antimonide and an antimony-containing compound semiconductor material; the binary antimonide includes at least one of gallium antimonide and indium antimonide; the multinary antimonide includes at least one of aluminum gallium antimony, indium gallium antimony and aluminum gallium indium antimony; the antimony-containing compound semiconductor material includes at least one of antimony silver ore and antimony palladium ore.

3. The antimonide single transverse mode external cavity laser according to claim 1 or 2, characterized in that: The front cavity surface of the antimonide gain chip is plated with an antireflection film, and the rear cavity surface is plated with a reflection film.

4. The antimonide single transverse mode external cavity laser according to claim 3, characterized in that: The transmittance of the antireflection film on the front cavity surface of the antimonide gain chip is greater than 99.5%; the reflectivity of the reflection film on the back cavity surface of the antimonide gain chip is greater than 99%.

5. The antimonide single transverse mode external cavity laser according to claim 3, characterized in that: The external cavity feedback module also includes a collimator mirror arranged along the optical path; the collimator mirror is an aspherical lens, which is used to expand and collimate the incident laser light beam.

6. The antimonide single transverse mode external cavity laser according to claim 5, characterized in that: The blazed grating is controlled to rotate by a rotating mechanism; The rotating mechanism includes at least a rotating motor, a position sensor and a controller; the rotating motor is arranged at the edge of the blazing grating to drive the blazing grating to rotate; the position sensor is arranged between the rotating motor and the controller to measure the rotation angle of the blazing grating and feed it back to the controller; the controller is connected to the rotating motor to control the rotation direction of the blazing grating and adjust the rotation angle around the axis.

7. The antimonide single transverse mode external cavity laser according to claim 3, characterized in that: The laser output module at least includes a single-mode optical fiber, which is directly coupled to the antimonide gain chip.

8. The antimonide single transverse mode external cavity laser according to claim 7, characterized in that: The light incident end face of the single-mode optical fiber has two symmetrically arranged inclined surfaces to form a wedge-shaped incident end face, and the wedge-shaped incident end face is processed into an optical fiber microlens.

9. The antimonide single transverse mode external cavity laser according to claim 8, characterized in that: The included angle of the wedge-shaped incident end face of the single-mode optical fiber is 60°-120°.

10. The antimonide single transverse mode external cavity laser according to claim 7, characterized in that: The wedge-shaped incident end face of the single-mode optical fiber is plated with an anti-reflection film, and the transmittance of the anti-reflection film on the wedge-shaped incident end face of the single-mode optical fiber is greater than 99%.

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