Ridge waveguide semiconductor laser, preparation method thereof and improvement method of horizontal divergence angle of ridge waveguide semiconductor laser
By mediation of the cycle and duty cycle of the grille structure in the spinal tiger semiconductor lasers, the problem of poor quality and insufficient reliability at high -power semiconductor laser beams and insufficient reliability at high temperatures, and achieve lower threshold currents and smaller levels of scattered scattered corners. Improve the output power and beam quality of the laser.
Patent Information
- Application Number
- CN202411300961.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-18
- Publication Date
- 2025-01-21
AI Technical Summary
The poor beam quality of high-power semiconductor lasers and insufficient reliability at high temperatures cannot meet the needs of practical applications.
Adopting the method of landscape -based landscape and spinal waveguard semiconductor laser preparation method, through the mediation cycle and duty occupation ratio of the grating structure, the steps of the effective refractive index on both sides of the wave guide can be reduced. Uniformly distributed.
The threshold current of the semiconductor laser is reduced, the horizontal divergence angle is reduced, the beam quality and high temperature characteristics are improved, and the output power is increased.
Smart Images
Figure CN119340787A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of semiconductor lasers, and in particular relates to a ridge waveguide-based photolithography pattern, a ridge waveguide semiconductor laser and a preparation method thereof, and a method for improving the horizontal divergence angle thereof. Background Art
[0002] With the development of science and technology, semiconductor lasers, with their high efficiency, high stability, compact size and flexible modulation characteristics, are leading the development of laser technology and shining in many fields such as industry, medical treatment, and scientific research. With the deepening of semiconductor laser applications, the requirements for them are getting higher and higher. Under the application requirements of high power, the beam quality of semiconductor lasers is getting worse and worse. Under the application requirements of high temperature environments, the power attenuation of semiconductor lasers is also getting larger and larger, which cannot meet the actual use needs.
[0003] At present, the horizontal divergence angle of high-power semiconductor lasers affects the beam quality of semiconductor lasers, and the beam quality of semiconductor lasers determines the brightness of semiconductor lasers. In practical applications, the higher the brightness of the laser, the higher the efficiency. The epitaxial growth direction of semiconductor lasers is vertical, and the waveguide is formed by the refractive index of the epitaxial material. In the horizontal direction, the material outside the light-emitting area needs to be etched away to form a ridge waveguide. Under the condition of a certain epitaxial structure, the height of the ridge waveguide affects the horizontal divergence angle and the threshold current. When the height of the ridge waveguide is low, the horizontal divergence angle is small, but the threshold current is large. When the height of the ridge waveguide is high, although the threshold current decreases, the horizontal divergence angle becomes larger. Summary of the invention
[0004] In order to overcome the poor beam quality and poor reliability of high-power semiconductor lasers at high temperatures, the present invention proposes a ridge waveguide-based photolithography pattern, a ridge waveguide semiconductor laser and a preparation method thereof, and a method for improving the horizontal divergence angle thereof.
[0005] The technical solution adopted by the present invention to solve the technical problem is:
[0006] A method for preparing a ridge waveguide semiconductor laser comprises the following steps:
[0007] Step 1: Using the wafer as a substrate, a photolithography process is used to prepare a photolithography pattern.
[0008] The etched area of the photolithography pattern is a light-transmitting and light-opaque grating structure.
[0009] Step 2: Place the photolithography pattern in RIE or ICP equipment and use dry etching process to form a ridge waveguide to obtain a ridge waveguide semiconductor laser.
[0010] In the above-mentioned preparation method, in step 1, the etching area of the photolithography pattern can also be a local light-transmitting structure.
[0011] A ridge waveguide-based photolithography layout, characterized by comprising an etching area.
[0012] The etched area is a light-transmitting and light-impermeable grating structure.
[0013] In the above-mentioned ridge waveguide-based photolithography pattern, the etched area can also be a local light-transmitting structure
[0014] A ridge waveguide semiconductor laser comprises the ridge waveguide-based photolithography pattern.
[0015] The etched area of the photolithography pattern is a light-transmitting and light-impermeable grating structure, or a partially light-transmitting structure.
[0016] A ridge waveguide is formed.
[0017] A method for improving the horizontal divergence angle of a ridge waveguide semiconductor laser, using the ridge waveguide semiconductor laser.
[0018] The above-mentioned method for improving the horizontal divergence angle of the ridge waveguide semiconductor laser reduces the step difference of the effective refractive index of the areas on both sides of the waveguide by adjusting the period and duty cycle of the grating structure.
[0019] The above-mentioned method for improving the horizontal divergence angle of the ridge waveguide semiconductor laser achieves uniform distribution of the high-order mode far-field light field by adjusting the period and duty cycle of the grating structure.
[0020] The beneficial effects of the present invention are:
[0021] A method for improving the horizontal divergence angle of a semiconductor laser. A new type of ridge waveguide is designed. This structure has three main functions. First, the height of the etched ridge waveguide can be very large, reducing the threshold current; second, the period and duty cycle of the grating can be adjusted to adjust the effective refractive index of the areas on both sides of the ridge waveguide, reduce the step difference of the refractive index, and make the near-field light field spot of the semiconductor laser larger. When the near-field light field spot is larger, the far-field divergence angle becomes smaller; third, the period and duty cycle of the grating can be adjusted to adjust the high-order mode light field distribution, making the far-field light field distribution more uniform. This design will improve the high-temperature characteristics of semiconductor lasers, thereby increasing the output power and improving the beam quality of semiconductor lasers at high power. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is a schematic diagram of the structure of a conventional ridge waveguide semiconductor laser in the prior art;
[0023] Figure 2 is a schematic structural diagram of a ridge waveguide semiconductor laser according to embodiment 1 of the present invention;
[0024] Figure 3 It is a schematic diagram of the photolithography layout structure for forming a conventional ridge waveguide in the prior art;
[0025] Figure 4 is a schematic diagram of the structure of the photolithography pattern in the first embodiment of the invention;
[0026] Figure 5 is a schematic diagram of the structure of the photolithography pattern in the second embodiment of the invention;
[0027] Figure 6 It is a schematic diagram of the structure of a ridge waveguide semiconductor laser according to Example 2 of the present invention. DETAILED DESCRIPTION
[0028] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.
[0029] The present invention proposes a new method and structure, which can not only reduce the threshold current of semiconductor lasers, but also reduce the horizontal divergence angle of semiconductor lasers. In conventional ridge waveguide semiconductor lasers, ridge waveguides are formed by dry etching or wet etching, such as Figure 1 As shown, in this structure, when the epitaxial structure and the light-emitting width are constant, the higher the ridge waveguide height, the larger the divergence angle and the smaller the threshold current, while the lower the ridge waveguide height, the smaller the divergence angle and the larger the threshold current, which cannot be satisfied at the same time.
[0030] The present invention proposes a new structure, such as Figure 2 As shown, a grating structure is etched in the area next to the ridge waveguide. This structure has three main functions. First, the height of the etched ridge waveguide can be very large, thereby reducing the threshold current. Second, by adjusting the period and duty cycle of the grating, the effective refractive index of the areas on both sides of the ridge waveguide can be adjusted, reducing the step difference in the refractive index, and making the near-field light field spot of the semiconductor laser larger. When the near-field light field spot becomes larger, the far-field divergence angle becomes smaller. Third, by adjusting the period and duty cycle of the grating, the high-order mode light field distribution can be adjusted, making the far-field light field distribution more uniform.
[0031] In a conventional ridge waveguide semiconductor laser, the photolithography pattern for forming the ridge waveguide is as follows: Figure 3 As shown; the schematic diagram of the ridge waveguide semiconductor laser made using this photolithography pattern is shown Figure 1 shown.
[0032] Example 1
[0033] Design a photolithography pattern to form a ridge waveguide, and design the light-transmitting area of the photolithography pattern into a light-transmitting and light-impermeable grating structure, such as Figure 4 shown.
[0034] 1) A schematic diagram of a novel ridge waveguide semiconductor laser fabricated using the photolithography pattern of the first embodiment of the invention is shown in FIG. Figure 2 As shown;
[0035] 2) When the semiconductor laser wafer is taped out to make the ridge waveguide process, Figure 4 The photolithography pattern shown is subjected to a photolithography process;
[0036] 3) Place the semiconductor laser wafer that has completed the ridge waveguide lithography process into the RIE or ICP equipment and perform a dry etching process (wet etching process can also be achieved under larger grating periods and duty cycles) to form Figure 2 The new ridge waveguide semiconductor laser shown.
[0037] Example 2
[0038] Design the photolithography pattern to form the ridge waveguide, and design the light-transmitting area of the photolithography pattern into a partially light-transmitting structure, such as Figure 5 Shown
[0039] 1) A schematic diagram of a novel ridge waveguide semiconductor laser fabricated using the photolithography pattern of the second embodiment of the invention is shown in FIG. Figure 6 As shown;
[0040] 2) When the semiconductor laser wafer is taped out to make the ridge waveguide process, Figure 5 The photolithography pattern shown is subjected to a photolithography process;
[0041] 3) After the ridge waveguide lithography process, the semiconductor laser wafer is placed in the RIE or ICP equipment for dry etching (wet etching can also be achieved at larger grating periods and duty cycles) to form Figure 6 The new ridge waveguide semiconductor laser shown.
Claims
1. A method for preparing a ridge waveguide semiconductor laser, characterized in that: The following steps are involved: Step 1, using the wafer as a substrate and using a photolithography process to prepare a photolithography pattern; The etched area of the photolithography pattern is a light-transmitting and light-impermeable grating structure; Step 2, placing the photolithography pattern in RIE or ICP equipment, using dry etching or wet etching process to form a ridge waveguide; and obtaining a ridge waveguide semiconductor laser.
2. The preparation method according to claim 1, characterized in that: In the step 1, the etched area of the photolithography pattern may also be a local light-transmitting structure.
3. A ridge waveguide-based lithography layout, characterized in that: including an etched area; The etched area is a light-transmitting and light-impermeable grating structure.
4. The ridge waveguide-based lithography layout according to claim 3, characterized in that: The etched area may also be a local light-transmitting structure.
5. A ridge waveguide semiconductor laser, characterized in that: A ridge waveguide-based lithography pattern comprising the ridge waveguide-based lithography pattern according to claim 3 or 4; The etching area of the photolithography pattern is a light-transmitting and light-impermeable grating structure, or a partially light-transmitting structure; A ridge waveguide is formed.
6. A method for improving the horizontal divergence angle of a ridge waveguide semiconductor laser, characterized in that: Use the ridge waveguide semiconductor laser as claimed in claim 5.
7. The method for improving the horizontal divergence angle of a ridge waveguide semiconductor laser according to claim 6, characterized in that: By adjusting the period and duty cycle of the grating structure, the step difference of the effective refractive index on both sides of the waveguide can be reduced.
8. The method for improving the horizontal divergence angle of a ridge waveguide semiconductor laser according to claim 6, characterized in that: By adjusting the period and duty cycle of the grating structure, a uniform distribution of the high-order mode far-field light field can be achieved.