A surface-emitting tunable semiconductor laser and an optical device

Abstract

In an embodiment of the present invention, a surface-emitting tunable semiconductor laser and an optical device are provided, which include an edge-emitting component, a vertical reflection component, a piezoelectric component, an external cavity mirror, and a chip rear cavity mirror. The vertical reflection component has a 45-degree reflection inclined surface structure, a light incident surface, and a light exit surface. The piezoelectric component has a light passing hole. The edge-emitting component includes an active region. The light incident surface is attached to the side surface of the edge-emitting component and contacts one end of the active region. The light exit surface is attached to the piezoelectric component. An optical antireflection film is provided on the surface of the vertical reflection component that is attached to the piezoelectric component, and the 45-degree reflection inclined surface structure is coated with a high-reflection film. The optical axis of the active region is perpendicular to the optical axis of the light passing hole. An optical resonant cavity is formed by the chip rear cavity mirror, the active region, the vertical reflection component, the light passing hole, and the external cavity mirror. By the mechanical expansion and contraction effect generated by the piezoelectric component under the drive of an externally applied modulation voltage signal, the length of the optical resonant cavity is changed, achieving a higher laser output power, which is beneficial to expanding more application scenarios.

Description

Technical Field

[0001] The present invention relates to the field of laser semiconductors, and particularly to a surface-emitting tunable semiconductor laser and an optical device. Background Art

[0002] Tunable semiconductor lasers have advantages such as small volume, light weight, and low energy consumption, and are widely used in fields such as laser communication and laser sensing. Currently, relatively mature tunable semiconductor laser products can be mainly divided into two categories from the perspective of technical types: The first category is traditional chip-level lasers such as DFB lasers, DBR lasers, and VCSEL lasers. This type of laser has the advantages of single-chip operation, high reliability and stability, and realizes wavelength tuning by tuning the drive current or operating temperature. The main disadvantage is that the wavelength tuning range is very small, usually only at the level of a few nanometers. The second category is tunable semiconductor lasers based on an external cavity, which realize wavelength tuning by tuning the external cavity length or external optical elements with wavelength selectivity (such as diffraction gratings). This type of laser has outstanding advantages such as narrow spectral linewidth and large wavelength tuning range. The main disadvantage is that due to the addition of a macroscopic electromechanical system outside the chip, the reliability and stability are poor, and it is easily interfered by external environmental factors.

[0003] In recent years, products that integrate the advantages of the above two types of tunable semiconductor lasers have emerged. A more representative one is the VCSEL (Vertical-Cavity Surface-Emitting Laser) tunable semiconductor laser with a monolithic integrated MEMS (Micro-Electro-Mechanical System) external cavity structure. On the one hand, it has the characteristic of a large wavelength tuning range brought by the external cavity structure, and on the other hand, it also has the characteristics of high reliability and stability brought by chip-level devices. Therefore, it has good development potential. However, the disadvantages of this commercial solution are also obvious: On the one hand, since the VCSEL structure is used as the construction basis, although a multi-quantum well active region is adopted, in order to ensure good output beam characteristics, the working area of the active region must be limited within a small aperture, so the laser output power is low. On the other hand, since GaAs-based active region materials are used, the laser operating wavelength is limited to the near-infrared band (0.7 μm - 1.1 μm), which all limits the application scenarios.

[0004] The above-mentioned commercial solution of the VCSEL tunable semiconductor laser with a MEMS external cavity structure has excellent characteristics such as single-frequency output and a large wavelength tuning range. Moreover, due to the use of a monolithic integrated structure, the reliability and stability are also relatively high. However, the disadvantages of this commercial solution are also obvious: on the one hand, since the VCSEL structure is used as the construction basis, although a multi-quantum well active region is adopted, in order to ensure the single-frequency output characteristic, the working area of the active region must be kept very small, so the laser output power is very low; on the other hand, due to the use of GaAs-based active region materials, the laser working wavelength is limited to the near-infrared band (0.7μm - 1.1μm), which all limit the application scenarios. Summary of the Invention

[0005] In view of this, an edge-emitting tunable semiconductor laser is provided in an embodiment of the present invention.

[0006] In a first aspect, the present invention provides an edge-emitting tunable semiconductor laser, including: an edge-emitting component, a vertical reflection component, a piezoelectric component, an external cavity mirror, and a chip rear cavity mirror. The vertical reflection component has a 45-degree reflection inclined surface structure, a light incident surface, and a light output surface. The piezoelectric component has a light passing hole. The edge-emitting component includes an active region. The light incident surface is attached to the side surface of the edge-emitting component and contacts one end of the active region. The light output surface is attached to the piezoelectric component. An optical antireflection film is provided on the surface where the vertical reflection component is attached to the piezoelectric component. The 45-degree reflection inclined surface structure is coated with a high-reflection film. The optical axis of the active region is perpendicular to the optical axis of the light passing hole. An optical resonant cavity is formed by the chip rear cavity mirror, the active region, the vertical reflection component, the light passing hole, and the external cavity mirror.

[0007] As an optional solution, the edge-emitting component sequentially includes a P-side electrode, a grating, an upper waveguide layer, the active region, a lower waveguide layer, and an N-side electrode from top to bottom. The active region is located between the upper waveguide layer and the lower waveguide layer.

[0008] As an optional solution, the piezoelectric component includes a first electrode and a second electrode. The first electrode covers the first surface area of the piezoelectric component. The second electrode covers the second surface area of the piezoelectric component. The first surface area and the second surface area are electrically insulated from each other. The second electrode is electrically connected to the P-side electrode.

[0009] As an optional solution, the chip rear cavity mirror has a natural cleavage surface structure or an optical coating structure.

[0010] As an optional solution, the piezoelectric component uses a piezoelectric thin film.

[0011] As an optional solution, the piezoelectric component and the edge-emitting component are connected by a bonding method.

[0012] As an alternative, the edge-emitting component employs a distributed Bragg reflector (DBR) edge-emitting laser or a distributed feedback (DFB) edge-emitting laser.

[0013] As an alternative, the edge-emitting component employs a gallium arsenide (GaAs)-based laser or an indium phosphide (InP)-based laser.

[0014] As an alternative, it further includes a ceramic heat sink having at least three electrode patterns which are respectively connected to the P-side electrode, the N-side electrode, and the first electrode.

[0015] In a second aspect, the present invention provides an optical device having the surface-emitting tunable semiconductor laser as described above.

[0016] An edge-emitting tunable semiconductor laser and an optical device provided in an embodiment of the present invention include an edge-emitting component, a vertical reflection component, a piezoelectric component, an external cavity mirror, and a chip rear cavity mirror. The vertical reflection component has a 45-degree reflection inclined surface structure, a light incident surface, and a light exit surface. The piezoelectric component has a light passing hole. The edge-emitting component includes an active region. The light incident surface is attached to the side surface of the edge-emitting component and contacts one end of the active region. The light exit surface is attached to the piezoelectric component. An optical antireflection film is provided on the surface where the vertical reflection component is attached to the piezoelectric component. The 45-degree reflection inclined surface structure is coated with a high reflection film. The optical axis of the active region is perpendicular to the optical axis of the light passing hole. An optical resonance cavity is formed by the chip rear cavity mirror, the active region, the vertical reflection component, the light passing hole, and the external cavity mirror. By the piezoelectric component generating a mechanical expansion and contraction effect under the drive of an externally applied modulation voltage signal, the length of the optical resonance cavity can be changed, thereby realizing the tuning of the working wavelength of the laser, achieving a higher laser output power, and the laser working wavelength can be broadened to the short-wave infrared band (1.1 μm - 2 μm), which is beneficial to expanding more application scenarios. Description of the Drawings

[0017] Figure 1 It is a schematic structural diagram of a surface-emitting tunable semiconductor laser provided in an embodiment of the present invention.

[0018] Reference Numerals: Optical antireflection film 1, Piezoelectric component 2, External cavity mirror 3, Chip rear cavity mirror 4, P-side electrode 5, Active region 6, N-side electrode 7, First electrode 8, Second electrode 9, Grating 10, Upper waveguide layer 11, Lower waveguide layer 12, Vertical reflection component 13, High reflection film 14. Detailed Embodiments

[0019] To enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] The terms "first", "second", "third", "fourth", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments described herein can be implemented in an order other than that shown or described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0021] Combined with Figure 1 As shown, the present invention provides an edge-emitting tunable semiconductor laser, comprising: an edge-emitting component, a vertical reflection component 13. The vertical reflection component 13 has a 45-degree reflection inclined surface structure, a light incident surface and a light output surface. The piezoelectric component 2 has a light passing hole. The edge-emitting component includes an active region 6, and the function of the active region 6 is to generate lasing photons through the excitation of a driving current. The light incident surface is attached to the side surface of the edge-emitting component and contacts one end of the active region 6. The light output surface is attached to the piezoelectric component 2. An optical antireflection film 1 is provided on the surface of the vertical reflection component 13 that is attached to the piezoelectric component 2. Through the optical antireflection film 1, the reflectivity of the interface is made as low as possible to reduce the beam propagation loss. The 45-degree reflection inclined surface structure is coated with a high-reflection film 14. The optical axis of the active region 6 is perpendicular to the optical axis of the light passing hole. The high-reflection film forms a 45-degree angle with the horizontal direction, and can reflect the horizontal light into vertical light and smoothly enter the light passing hole. An optical resonant cavity is formed by the chip rear cavity mirror 4, the active region 6, the vertical reflection component 13, the light passing hole and the external cavity mirror 3.

[0022] Specifically, a bonding process can be used to connect the vertical emission component and the edge emission component. The function of the vertical reflection component is to convert the horizontally propagating light beam into a vertically upward propagating light beam. The material of the vertical reflection component is preferably a high refractive index semiconductor material, such as silicon, germanium, GaAs, InP, etc. One of the advantages is that it is easy to match the refractive index with the active region material of the edge-emitting laser. Another advantage is that the angular diffusion of the light beam during propagation inside the reflection block is very small, and it can be flexibly selected according to needs.

[0023] It should be noted that the reflectivities of the chip rear mirror 4 and the external mirror 3 in the embodiments of the present invention need to be carefully designed. While ensuring the resonance cavity oscillation effect, the single longitudinal mode selection effect of the edge-emitting laser's own DBR (Distributed Feedback) or DFB (Distributed Bragg Reflction) cannot be damaged, otherwise it will lead to the adverse consequence of multi-longitudinal mode lasing. The specific numerical values of the reflectivities are not limited in this patent.

[0024] In addition, a refractive index matching liquid or an optical coating is provided at the interface between the light passing hole and the light emitting surface of the edge emission component, so that the reflectivity of the interface is as low as possible to reduce the light beam propagation loss.

[0025] As an optional solution, the edge emission component sequentially includes a P-plane electrode 5, a grating 10, an upper waveguide layer 11, the active region 6, a lower waveguide layer 12, and an N-plane electrode 7 from top to bottom. The active region 6 is located between the upper waveguide layer 11 and the lower waveguide layer 12. It should be noted that the components of the edge reflection component can be flexibly selected according to the needs of those skilled in the art and are not limited herein.

[0026] In some embodiments, the edge emission component adopts a distributed Bragg reflector DBR edge-emitting laser or a distributed feedback DFB edge-emitting laser, which can be flexibly selected according to the needs of those skilled in the art and are not limited herein.

[0027] In some embodiments, the edge emission component adopts a gallium arsenide GaAs-based laser or an indium phosphide InP-based laser, which can be flexibly selected according to the needs of those skilled in the art and are not limited herein.

[0028] As an alternative, the piezoelectric component 2 includes a first electrode 8 and a second electrode 9. The first electrode 8 covers a first surface area of the piezoelectric component 2. The first surface area can be the upper surface of the piezoelectric component as the gold wire bonding pad area, or the first surface area can be the left side covering the left surface and the upper surface of the piezoelectric component as the gold wire bonding pad area. The second electrode 9 covers a second surface area of the piezoelectric component 2. The first surface area can be the lower surface of the piezoelectric component as the gold wire bonding pad area. The first surface area and the second surface area are electrically insulated from each other. The P-side electrode of the edge-emitting component is electrically connected to the second electrode of the piezoelectric component, that is, a common electrode is formed. Those of ordinary skill in the art should understand that there is no limitation in this regard.

[0029] Specifically, the P-side electrode of the edge-emitting component and the second electrode of the piezoelectric component can be electrically connected by welding or bonding. It is worth mentioning that, preferably, the length of the P-side electrode is longer than the length of the piezoelectric component.

[0030] As an alternative, the chip rear mirror 4 has a natural cleavage plane structure or an optical coating structure, which can be flexibly selected according to the needs of those skilled in the art, and there is no limitation in this regard.

[0031] As an alternative, the piezoelectric component 2 is made of a piezoelectric thin film, which can be flexibly selected according to the needs of those skilled in the art, and there is no limitation in this regard.

[0032] As an alternative, the piezoelectric component 2 and the edge-emitting component are connected by bonding, which can be flexibly selected according to the needs of those skilled in the art, and there is no limitation in this regard.

[0033] As an alternative, a ceramic heat sink is further included. The ceramic heat sink has at least 4 electrode patterns, and the at least 4 electrode patterns are electrically connected to the P-side electrode 5, the N-side electrode 7, the first electrode 8, and the second electrode 9 respectively.

[0034] The working principle of the edge-emitting tunable semiconductor laser provided in the embodiment of the present invention can be realized. The piezoelectric component 2 generates a mechanical expansion and contraction effect under the drive of an externally applied modulation voltage signal, which can change the length of the optical resonator, thereby realizing the tuning of the working wavelength of the laser. Due to the relatively large working area of the active region 6 of the edge-emitting laser, the output optical power can usually be much higher than that of a VCSEL (Vertical-Cavity Surface-Emitting Laser). The edge-emitting laser adopted in this application can be either a GaAs-based laser or an InP-based laser, so the working wavelength can in principle be extended to the working wavelength of the adopted edge-emitting laser.

[0035] An edge-emitting tunable semiconductor laser provided in an embodiment of the present invention includes an edge-emitting component and a vertical reflection component 13. The vertical reflection component 13 has a 45-degree reflection inclined plane structure, a light incident surface and a light exit surface. The piezoelectric component 2 has a light passing hole. The edge-emitting component includes an active region 6, and the function of the active region 6 is to generate lasing photons through the excitation of a driving current. The light incident surface is attached to the side surface of the edge-emitting component and contacts one end of the active region 6. The light exit surface is attached to the piezoelectric component 2. An optical antireflection film 1 is provided on the surface of the vertical reflection component 13 that is attached to the piezoelectric component 2. Through the optical antireflection film 1, the reflectivity of the interface is made as low as possible to reduce the beam propagation loss. The 45-degree reflection inclined plane structure is coated with a high reflection film 14. The optical axis of the active region 6 is perpendicular to the optical axis of the light passing hole. The high reflection film forms a 45-degree angle with the horizontal direction, and can reflect the horizontal light into vertical light and smoothly enter the light passing hole. An optical resonant cavity is formed by the chip rear cavity mirror 4, the active region 6, the vertical reflection component 13, the light passing hole and the external cavity mirror 3. By the piezoelectric component 2 generating a mechanical expansion and contraction effect under the drive of an externally applied modulation voltage signal, the length of the optical resonant cavity can be changed, thereby realizing the tuning of the working wavelength of the laser, achieving a higher laser output power, and the laser working wavelength can be broadened to the short-wave infrared band (1.1 μm - 2 μm), which is beneficial to expanding more application scenarios.

[0036] Correspondingly, an embodiment of the present invention further provides an optical device having the surface-emitting tunable semiconductor laser as described above.

[0037] An optical device provided in an embodiment of the present invention can achieve a higher laser output power, and the laser working wavelength can be broadened to the short-wave infrared band (1.1 μm - 2 μm), which is beneficial to expanding more application scenarios.

[0038] It should be understood that various forms of the processes shown above can be used, reordering, adding or deleting steps. For example, the steps recorded in the present disclosure can be executed in parallel, sequentially or in different orders, as long as the desired results of the technical solutions disclosed in the present invention can be achieved, and no limitation is made herein.

[0039] The above specific embodiments do not constitute a limitation to the protection scope of the present invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A surface-emitting tunable semiconductor laser, characterized in that, Comprising: An edge-emitting component, a vertical reflection component, a piezoelectric component, an external cavity mirror, and a chip rear cavity mirror. The vertical reflection component has a 45-degree reflection inclined plane structure, a light incident surface, and a light exit surface. The piezoelectric component has a light passing hole. The edge-emitting component includes an active region. The light incident surface is attached to the side surface of the edge-emitting component and contacts one end of the active region. The light exit surface is attached to the piezoelectric component. An optical antireflection film is provided on the surface where the vertical reflection component is attached to the piezoelectric component. The 45-degree reflection inclined plane structure is coated with a high reflection film. The optical axis of the active region is perpendicular to the optical axis of the light passing hole. An optical resonant cavity is formed by the chip rear cavity mirror, the active region, the vertical reflection component, the light passing hole, and the external cavity mirror.

2. The surface-emitting tunable semiconductor laser according to claim 1, characterized in that, The edge-emitting component sequentially includes a P-side electrode, a grating, an upper waveguide layer, the active region, a lower waveguide layer, and an N-side electrode from top to bottom. The active region is located between the upper waveguide layer and the lower waveguide layer.

3. The surface-emitting tunable semiconductor laser according to claim 2, characterized in that, The piezoelectric component includes a first electrode and a second electrode. The first electrode covers the first surface area of the piezoelectric component. The second electrode covers the second surface area of the piezoelectric component. The first surface area and the second surface area are electrically insulated from each other. The second electrode is electrically connected to the P-side electrode.

4. The surface-emitting tunable semiconductor laser according to claim 1, characterized in that, The chip rear cavity mirror has a natural cleavage plane structure or an optical coating structure.

5. The surface-emitting tunable semiconductor laser according to claim 1, characterized in that, The piezoelectric component uses a piezoelectric thin film.

6. The surface-emitting tunable semiconductor laser according to claim 1 or 5, characterized in that, The piezoelectric component and the edge-emitting component are connected by a bonding method.

7. The surface-emitting tunable semiconductor laser according to claim 1, characterized in that, The edge-emitting component uses a distributed Bragg reflector DBR edge-emitting laser or a distributed feedback DFB edge-emitting laser.

8. The surface-emitting tunable semiconductor laser according to claim 1 or 7, characterized in that, The edge-emitting component uses a gallium arsenide GaAs-based laser or an indium phosphide InP-based laser.

9. The surface-emitting tunable semiconductor laser according to claim 3, characterized in that, It further includes a ceramic heat sink. The ceramic heat sink has at least three electrode patterns, and the at least three electrode patterns are respectively electrically connected to the P-side electrode, the N-side electrode, and the first electrode.

10. An optical device, characterized in that, There is a surface-emitting tunable semiconductor laser as described in any one of claims 1 to 9.

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