Pulse modulation laser array chip based on double-SOA structure
By using a pulse-modulated laser array chip with a dual SOA structure, and by combining photonic lead waveguide structure and current modulation, the problems of light leakage and uneven output in DFB laser arrays have been solved, achieving a wider wavelength tuning range and higher output power balance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING UNIVERSTIY SUZHOU HIGH TECH INST
- Filing Date
- 2026-03-25
- Publication Date
- 2026-05-08
AI Technical Summary
Existing SOA structures suffer from light leakage and uneven output power in DFB laser arrays, especially at the edges of the gain spectrum where lasers exhibit light leakage and lower output power than the central lasers.
A pulse-modulated laser array chip with a dual SOA structure is used to couple the semiconductor laser array chip and the active photonic integrated chip using a photonic lead waveguide structure. By using different current combination modulation methods, gain spectrum coverage and power balance can be achieved, including designing a height difference compensation on the substrate and introducing a phase shift structure on the grating layer to adjust the lasing wavelength.
It significantly reduces the size, weight, and power consumption of pulsed light sources, solves the light leakage problem, expands the wavelength tuning range, enables the combined output of multiple laser arrays, and enhances output power equalization.
Smart Images
Figure CN122000792A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of optoelectronics technology, and more specifically to a pulse-modulated laser array chip based on a dual SOA structure. Background Technology
[0002] Currently, tunable semiconductor lasers are mainly classified into external cavity tunable lasers, tunable vertical cavity surface-emitting lasers, distributed Bragg reflector lasers, and distributed feedback laser (DFB) laser arrays. Among them, DFB laser arrays are widely used in communication, optically controlled phased array radar, gas concentration detection, and fiber optic sensing due to their advantages such as good single-mode stability, high output power, and good direct modulation performance.
[0003] DFB laser arrays can generally be divided into three parts: laser structure, beam combiner structure, and SOA structure. Among them, the SOA structure can amplify and equalize the output light of different wavelengths, and can also pulse modulate the output light to realize an on-chip integrated pulse-modulated tunable laser.
[0004] To achieve the widest possible tuning range, the laser wavelength must completely cover the gain spectrum of the active region. However, the SOA structure exhibits significant differences in gain and loss for different wavelengths of light. Generally, the SOA has the highest gain and loss for the center wavelength of the active region's gain spectrum, while the gain and loss are lower for the edges of the gain spectrum. This leads to light leakage in DFB laser arrays where lasers located at the edge of the gain spectrum experience lower losses when the SOA is not powered, resulting in significantly lower output power compared to other lasers when the SOA is powered. Existing solutions involve applying different currents to the SOA to balance the differences in output power between different lasers, but this method does not solve the light leakage problem.
[0005] Therefore, how to design a pulse-modulated laser array chip based on a dual SOA structure to solve the light leakage phenomenon is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention
[0006] In view of the above problems, the present invention is proposed to provide a pulse modulation laser array chip based on a dual SOA structure to overcome or at least partially solve the above problems, for realizing pulse modulation of light of different wavelengths, significantly reducing the size, weight and power consumption of pulse light sources, solving the problem of light leakage caused by the output wavelength deviating from the center of the gain spectrum when using laser arrays as light sources, and realizing the combined output of multiple laser arrays, thereby expanding the wavelength tuning range.
[0007] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, embodiments of the present invention provide a pulse-modulated laser array chip based on a dual SOA structure, comprising: a substrate, a semiconductor laser array chip, an active photonic integrated chip, and a photonic wire waveguide structure; Both the semiconductor laser array chip and the active photonic integrated chip are placed on the substrate; The semiconductor laser array chip and the active photonic integrated chip are coupled together via a photonic wire waveguide structure.
[0008] Preferably, the substrate is a tungsten-copper substrate; Both the semiconductor laser array chip and the active photonic integrated chip are mounted on a tungsten copper substrate, and the height difference between different chips is compensated by the shape design of the tungsten copper substrate. The semiconductor laser array chip and the active photonic integrated chip are both mounted on their respective thin-film circuits, and are used to provide driving current and output electrical signals, respectively.
[0009] Preferably, the end faces of the semiconductor laser array chip, the active photonic integrated chip, and the photonic lead waveguide structure are all coated with an anti-reflection film optimized for the photonic lead waveguide structure to prevent end face reflection.
[0010] Preferably, the active photonic integrated chip includes an SOA multiplexing chip or an SOA chip.
[0011] Preferably, the semiconductor laser array chip includes a laser, a Y-branch waveguide structure, and a first SOA structure; The lasers serve as the light source, arranged in a 4×4 structure to form a 16-channel laser array; the two input waveguides of the Y-branch waveguide structure are respectively connected to two parallel 1×4 laser arrays to complete 8-channel combined output; the first SOA structure is connected to the output waveguide of the Y-branch waveguide structure for optical amplification or pulse modulation.
[0012] Preferably, the SOA multiplexing chip includes a multiplexing structure and a second SOA structure. The two input waveguides of the multiplexing structure are connected to the first SOA structure through the photonic lead waveguide structure to complete 16-channel multiplexing output. The second SOA structure is connected to the output waveguide of the multiplexing structure for optical amplification or pulse modulation.
[0013] Preferably, the semiconductor laser array chip includes a laser, a cascaded Y-branch waveguide structure, and a first SOA structure; The lasers serve as the light source, arranged in a 4×4 structure to form a 16-channel laser array; the input waveguides of the cascaded Y-branch waveguide structure are respectively connected to two parallel 2×4 laser arrays to complete the 16-channel combined output; the first SOA structure is connected to the output waveguide of the cascaded Y-branch waveguide structure for optical amplification or pulse modulation.
[0014] Preferably, the SOA chip is connected to the first SOA structure through the photonic lead waveguide structure.
[0015] Preferably, the semiconductor laser array chip includes a grating layer fabricated based on reconstructed equivalent chirp technology. A sampling structure is fabricated in the grating unit through a single holographic exposure and a single sampling photolithography step. A phase shift structure corresponding to the sampling structure is introduced in the +1 level grating unit. The +1 level grating unit is used as a resonant cavity. Each channel in the laser array achieves different lasing wavelengths by setting different sampling periods for different sampling structures, as shown in the following formula:
[0016] in, λ represents the effective refractive index, and λ represents the lasing wavelength. Indicates the sampling period. This represents the uniform grating period defined in holographic exposure.
[0017] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects: 1. This invention uses a dual SOA structure. The gain spectrum of the two SOA covers the lasing wavelength of all lasers, which solves the light leakage problem that exists in general laser arrays. In addition, the modulation range of the two SOA is larger, which improves the extinction ratio.
[0018] 2. This invention can realize the combined output of multiple laser arrays, increasing the number of laser channels and expanding the wavelength tuning range.
[0019] 3. This invention uses photonic wire bonding technology to build a path between the semiconductor laser array chip and the SOA multiplexing chip, achieving more compact chip integration. The integrated chip area is less different from that of a typical laser array chip. Attached Figure Description
[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.
[0021] Figure 1 This is a schematic diagram of the structure of the pulse-modulated laser array chip in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the structure of the pulse-modulated laser array chip in Embodiment 2 of the present invention; Figure 3 This is a schematic diagram of the SOA power supply scheme for the pulse-modulated laser array chip of the present invention; Figure 4 The gain spectra of the two SOA structures in the pulse-modulated laser array chip of this invention are shown. Explanation of markings in the diagram: 1-Substrate; 2-Semiconductor laser array chip; 3-SOA combiner chip; 4-Photonic lead waveguide structure; 5-SOA chip; 201-Laser; 202-Y-branch waveguide; 203-First SOA structure; 204-Cascaded Y-branch waveguide; 301-Combiner structure; 302-Second SOA structure. Detailed Implementation
[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0023] Example 1 This embodiment provides a pulse-modulated laser array chip based on a dual SOA structure, such as... Figure 1 It includes: substrate 1, semiconductor laser array chip 2, SOA wave combiner chip 3 and photonic lead waveguide structure 4.
[0024] The semiconductor laser array chip 2 and the SOA wave combiner chip 3 are both placed on the substrate 1 and are coupled to each other through the photonic lead waveguide structure 4.
[0025] The end faces of the semiconductor laser array chip 2, SOA multiplexing chip 3 and photonic lead waveguide structure 4 are all coated with anti-reflection films optimized for the photonic lead waveguide structure to prevent end face reflection.
[0026] More specifically, substrate 1 is a tungsten-copper substrate; semiconductor laser array chip 2 and SOA combiner chip 3 are both mounted on the tungsten-copper substrate, and the height difference between different chips is compensated by the shape design of the tungsten-copper substrate; semiconductor laser array chip 2 and SOA combiner chip 3 are both mounted on their respective thin-film circuits, which are used to provide drive current and output electrical signals, respectively.
[0027] The semiconductor laser array chip 2 includes: a laser 201, a Y-branch waveguide structure 202, and a first SOA structure 203. The lasers 201 serve as the light source, with 16 lasers arranged in a 4×4 configuration to form a 16-channel laser array. The two input waveguides of the Y-branch waveguide structure 202 are connected to two parallel 1×4 laser arrays, completing an 8-channel combined output. The first SOA structure 203 is connected to the output waveguide of the Y-branch waveguide structure 202 for optical amplification or pulse modulation. The SOA combined chip 3 and the active region multi-quantum-well structure of the semiconductor laser array chip 2 have different material compositions and quantum well thicknesses, resulting in different gain spectra to cover the lasing wavelengths of all lasers.
[0028] By applying a specific current combination to the SOA multiplexing chip 3 and the first SOA structure 203 of the semiconductor laser array chip, optical wave amplification and pulse modulation are achieved. When neither the SOA multiplexing chip 3 nor the first SOA structure 203 is powered, the maximum output optical power should be below -40dBm.
[0029] Specifically, the semiconductor laser array chip 2 has a grating layer, which is fabricated based on the reconstructed equivalent chirp technique. A sampling structure is created in the grating unit through a single holographic exposure and a single sampling photolithography step. A phase shift structure corresponding to the sampling structure is introduced in the +1 level grating unit. Using the +1 level grating unit as a resonant cavity, different lasing wavelengths are achieved by adjusting the sampling period of the sampling structure, as shown in the following formula:
[0030] in, λ represents the effective refractive index, and λ represents the lasing wavelength. Indicates the sampling period. This represents the uniform grating period defined in holographic exposure.
[0031] The SOA multiplexing chip 3 includes a multiplexing structure 301 and a second SOA structure 302. The two input waveguides of the multiplexing structure 301 are connected to the first SOA structure 203 through a photonic lead waveguide structure 4 to complete 16-channel multiplexing output. The second SOA structure 302 is connected to the output waveguide of the multiplexing structure 301 to perform optical amplification or pulse modulation.
[0032] Example 2 like Figure 2 As shown, compared with Embodiment 1, the Y-branch waveguide 202 in the semiconductor laser array chip 2 is replaced with a cascaded Y-branch waveguide 204, and the SOA multiplexing chip 3 is replaced with an SOA chip 5. Specifically, the SOA chip 5 removes the multiplexing structure 301 from the SOA multiplexing chip 3, retaining only the second SOA structure 302.
[0033] Specifically, the semiconductor laser array chip 2 includes a laser 201, a cascaded Y-branch waveguide structure 204, and a first SOA structure 203. The laser 201 serves as the light source, arranged in a 4×4 structure to form a 16-channel laser array. The input waveguides of the cascaded Y-branch waveguide structure 204 are connected to two parallel 2×4 laser arrays, completing the 16-channel combined output. The first SOA structure 203 is connected to the output waveguide of the cascaded Y-branch waveguide structure for optical amplification or pulse modulation. The SOA chip 5 is connected to the first SOA structure 203 via a photonic lead waveguide structure 4. The SOA chip 5 and the active region multi-quantum well structure of the semiconductor laser array chip 2 have different material compositions and quantum well thicknesses, resulting in different gain spectra to cover the lasing wavelengths of all lasers.
[0034] By applying a specific combination of currents to SOA chip 5 and the first SOA structure 203 of the semiconductor laser array chip, optical wave amplification and pulse modulation are achieved. When neither SOA chip 5 nor the first SOA structure 203 is powered, the maximum output optical power should be below -40dBm. The configuration of the remaining structures is the same as in Embodiment 1, and will not be described again here.
[0035] It is important to note that while cascaded Y-branch waveguide 204 can achieve laser arrays with a larger number of channels, the output power and yield will decrease exponentially due to the combined losses of the Y-branch waveguide and the laser yield. Using Y-branch waveguide 202 can reduce combining losses and increase output power, but the number of channels in the laser array is limited, resulting in lower integration. Using SOA combining chip 3 can achieve the combined output of multiple laser arrays, but it requires high uniformity of coupling loss in the photonic lead waveguide structure; large differences in loss will lead to large power differences between different wavelengths. When using SOA chip, only a single photonic lead waveguide structure is used, so there is no need to consider the uniformity of coupling loss, but it cannot achieve the combined output of multiple laser arrays.
[0036] For usage, please refer to the appendix. Figure 3 Different SOA power supply schemes are used for the outputs of different channels in the laser array. In (a), no power supply is applied to either SOA; in (b), a pulsed current is applied to SOA1 and a constant current is applied to SOA2; in (c), a constant current is applied to SOA1 and a pulsed current is applied to SOA2. Taking Example 1 as an example, SOA1 is the first SOA structure 203, and SOA2 is the second SOA structure 302. The gain spectra of the two are as follows: Figure 4As shown. When emission stops, neither SOA is powered. When emission occurs from a channel closer to the center wavelength of the semiconductor laser array chip's gain, SOA1 is powered by a pulsed current, and SOA2 by a constant current. In this case, SOA1 undergoes pulse modulation, and SOA2 adjusts its output power. When emission occurs from a channel farther from the center wavelength of the laser array chip's gain, SOA1 is powered by a constant current, and SOA2 by a pulsed current. In this case, SOA1 adjusts its output power, and SOA2 performs pulse modulation. Besides this, other power-up schemes can be selected to achieve more complex modulation.
[0037] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.
[0038] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A pulse-modulated laser array chip based on a dual SOA structure, characterized in that, include: Substrates, semiconductor laser array chips, active photonic integrated chips, and photonic wire waveguide structures; Both the semiconductor laser array chip and the active photonic integrated chip are placed on the substrate; The semiconductor laser array chip and the active photonic integrated chip are coupled together via a photonic wire waveguide structure.
2. The pulse-modulated laser array chip based on a dual SOA structure as described in claim 1, characterized in that, The substrate is a tungsten-copper substrate; Both the semiconductor laser array chip and the active photonic integrated chip are mounted on a tungsten copper substrate, and the height difference between different chips is compensated by the shape design of the tungsten copper substrate. The semiconductor laser array chip and the active photonic integrated chip are both mounted on their respective thin-film circuits, and are used to provide driving current and output electrical signals, respectively.
3. The pulse-modulated laser array chip based on a dual SOA structure as described in claim 1, characterized in that, The end faces connecting the semiconductor laser array chip, the active photonic integrated chip, and the photonic wire waveguide structure are all coated with an anti-reflection film optimized for the photonic wire waveguide structure to prevent end face reflection.
4. The pulse-modulated laser array chip based on a dual SOA structure as described in claim 1, characterized in that, The active photonic integrated chip includes an SOA multiplexing chip or an SOA chip.
5. A pulse-modulated laser array chip based on a dual SOA structure as described in claim 4, characterized in that, The semiconductor laser array chip includes a laser, a Y-branch waveguide structure, and a first SOA structure; The lasers serve as the light source, arranged in a 4×4 structure to form a 16-channel laser array; the two input waveguides of the Y-branch waveguide structure are respectively connected to two parallel 1×4 laser arrays to complete 8-channel combined output; the first SOA structure is connected to the output waveguide of the Y-branch waveguide structure for optical amplification or pulse modulation.
6. A pulse-modulated laser array chip based on a dual SOA structure as described in claim 5, characterized in that, The SOA multiplexing chip includes a multiplexing structure and a second SOA structure. The two input waveguides of the multiplexing structure are connected to the first SOA structure through the photonic lead waveguide structure to complete 16-channel multiplexing output. The second SOA structure is connected to the output waveguide of the multiplexing structure to perform optical amplification or pulse modulation.
7. A pulse-modulated laser array chip based on a dual SOA structure as described in claim 4, characterized in that, The semiconductor laser array chip includes a laser, a cascaded Y-branch waveguide structure, and a first SOA structure; The lasers serve as the light source, arranged in a 4×4 structure to form a 16-channel laser array; the input waveguides of the cascaded Y-branch waveguide structure are respectively connected to two parallel 2×4 laser arrays to complete the 16-channel combined output; the first SOA structure is connected to the output waveguide of the cascaded Y-branch waveguide structure for optical amplification or pulse modulation.
8. A pulse-modulated laser array chip based on a dual SOA structure as described in claim 7, characterized in that, The SOA chip is connected to the first SOA structure through the photonic lead waveguide structure.
9. A pulse-modulated laser array chip based on a dual SOA structure as described in claim 1, characterized in that, The semiconductor laser array chip includes a grating layer fabricated using reconstructed equivalent chirp technology. A sampling structure is created in the grating unit through a single holographic exposure and a single sampling photolithography step. A phase shift structure corresponding to the sampling structure is introduced in the +1 level grating unit. The +1 level grating unit is used as a resonant cavity. Each channel in the laser array achieves different lasing wavelengths by setting different sampling periods for different sampling structures, as shown in the following formula: in, λ represents the effective refractive index, and λ represents the lasing wavelength. Indicates the sampling period. This represents the uniform grating period defined in holographic exposure.