A laser radar light source based on TO packaging

Abstract

The present invention relates to a TO-encapsulated laser radar light source, comprising a seed laser, a circulator, a beam combiner, a gain fiber, a pump stripper, a fiber reflector, an isolation filter, a beam combiner, a pump stripper, and a pulse pump. This TO-encapsulated fiber-coupled laser radar light source eliminates the single-clad amplifier in the system, simplifying the laser radar light source system architecture and improving system integration. Pump splitting reduces the number of pumps, achieving volume and cost control. It also facilitates pulse pump control and effectively suppresses spontaneous emission generated during the amplification process.

Description

Technical Field

[0001] The present invention belongs to the field of laser radar, and in particular relates to a laser radar light source based on TO packaging. Background Art

[0002] As the next technological blue ocean that could revolutionize human lifestyles, autonomous vehicle research is attracting increasing attention from both academia and industry. Within this field, achieving complete, accurate, and real-time three-dimensional environmental modeling has long been a key and challenging area of research. LiDAR (LiDAR), which can accurately capture three-dimensional environmental information through non-contact scanning, is widely used in autonomous vehicles.

[0003] In existing technology, most LiDAR light sources use a single-mode fiber-coupled semiconductor laser in a butterfly package as their seed light source. This butterfly package is bulky, and its maximum peak output power is typically only a few tens of milliwatts. When modulated at 5ns @ 500kHz, the average power is approximately 15μW, requiring an additional single-clad amplifier stage for further amplification. Consequently, LiDAR light sources based on butterfly packages suffer from complex system architectures, low integration, and high costs. Summary of the Invention

[0004] In order to solve the above problems, the present invention proposes a lidar light source based on TO packaging, which simplifies the lidar light source system structure and improves the system integration.

[0005] The present invention provides a laser radar light source based on TO packaging, which includes a seed source, a circulator, a first beam combiner, a first double-clad gain fiber, a fiber reflector, an isolation filter, a second double-clad gain fiber, a second beam combiner and a pulse pump source; wherein the seed source adopts a TO-packaged fiber-coupled semiconductor laser; the second beam combiner divides the pulse pump light output by the pulse pump source into a first pulse pump light and a second pulse pump light, which are used as pump lights of the first double-clad gain fiber and the second double-clad gain fiber respectively; the seed light output by the seed source passes through the first port of the circulator After input, it is output to the first combiner through the second port. The first combiner couples the first pulse pump light and the seed light into the first double-clad gain fiber. The amplified seed light returns to the first double-clad gain fiber through the fiber reflector and is amplified again before input to the second port of the circulator. After passing through the third port of the circulator, it is output to the isolation filter. The amplified seed light is input to the second double-clad gain fiber after passing through the isolation filter. The second combiner inputs the second pulse pump light in reverse into the second double-clad gain fiber. After being amplified by the second double-clad gain fiber, the seed light is output through the second combiner.

[0006] In one embodiment, the laser radar light source further includes a first cladding pump stripper disposed between the first double-clad gain fiber and the fiber reflector, and a second cladding pump stripper disposed between the isolation filter and the second double-clad gain fiber.

[0007] In one embodiment, the central wavelength of the seed source is 1550±2 nm, the peak power of the output light is 200 mW, the pulse width is adjustable from 0.5 to 250 ns, and the repetition frequency is adjustable from 1 to 1000 kHz.

[0008] In one embodiment, the maximum output power of the pulse pump source is 9 W, the central wavelength is 915 nm, the pulse width is adjustable from 1 to 500 ns, and the repetition frequency is adjustable from 1 to 3000 kHz.

[0009] In one embodiment, the power ratio of the first pulse pump light to the second pulse pump light is 1:9.

[0010] In one embodiment, the first double-clad gain fiber and the second double-clad gain fiber are both LMA-EYDF-12 / 130 optical fibers, with lengths of 1.5 m and 3 m, respectively.

[0011] In one embodiment, the pulse signal of the seed light is triggered at the trailing edge of the pulse of the pulse pump light and is injected into the gain fiber at the end of the pulse pump light.

[0012] The present invention has at least the following beneficial technical effects:

[0013] (1) A TO-encapsulated fiber-coupled 1550 nm LiDAR light source was used, eliminating the single-clad amplifier in the system, thereby simplifying the LiDAR light source system structure and improving the system integration. At a pulse width of 5 ns and a repetition frequency of 500 kHz, the final average output power of the LiDAR light source was 1.5 W.

[0014] (2) By using pump splitting, the number of pumps can be reduced, and volume and cost can be controlled. At the same time, pulsed pump control can be easily achieved, which can better suppress the amplified spontaneous emission effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0016] Figure 1 Schematic diagram of a TO-encapsulated laser radar light source according to the present invention;

[0017] Figure 2 This is the timing diagram of the pulse pump and seed light of the lidar light source. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0019] The present invention provides a TO package based laser radar light source, see the attached Figure 1 The lidar light source includes a seed source (Seed), a circulator (CIR), a first combiner (Combiner 1), a first double-clad gain fiber (EDF 1), a first cladding pump stripper (CPS 1), a fiber reflector (Mirror), an isolation filter (ISO+BP), a second cladding pump stripper (CPS 2), a second double-clad gain fiber (EDF 2), a second combiner (Combiner 2), and a pulsed pump source (LD).

[0020] The seed source uses a TO-encapsulated fiber-coupled semiconductor laser with a central wavelength of 1550±2 nm, an output peak power of 200 mW, an adjustable pulse width from 0.5 to 250 ns, and an adjustable repetition rate from 1 to 1000 kHz. At a pulse width of 5 ns and a repetition rate of 500 kHz, the seed source's average output power is 0.5 mW.

[0021] The pulse pump source has a maximum output power of 9W and a central wavelength of 915 nm. The pulse width is adjustable from 1 to 500 ns and the repetition frequency is adjustable from 1 to 3000 kHz. The timing of the pulse pump and seed light is as follows: Figure 2 The circuit structure used to control the timing of the pump pulse and seed light is not shown in the figure. The seed light pulse signal is triggered by the falling edge of the pump pulse and injected into the gain fiber at the end of the pump pulse.

[0022] The second combiner is a composite fiber optic device that simultaneously functions as a combiner and a pump splitter. 10% of the pump light power from the pulsed pump source is fed into the first combiner, while 90% is fed into the second combiner. Pump splitting reduces the number of pumps, controlling both size and cost. It also facilitates pulsed pump control and suppresses amplified spontaneous emission (ASE). Experimental comparisons using combiners with different pump light splitting ratios revealed that a 1:9 ratio yielded the highest amplification efficiency and minimized ASE generation.

[0023] The first double-clad gain fiber and the second double-clad gain fiber are both LMA-EYDF-12 / 130 optical fibers with lengths of 1.5 m and 3 m respectively.

[0024] The first port of the circulator is connected to the seed source, the signal end of the first combiner is connected to the second port of the circulator, the pump end of the first combiner is connected to the 10% splitting end of the second combiner, the output end of the first combiner is connected to one end of the first double-clad gain fiber, the input end of the first cladding pump stripper is connected to the other end of the first double-clad gain fiber, the output end of the first cladding pump stripper is connected to the input end of the fiber reflector, the third port of the circulator is connected to the input end of the isolation filter, the output end of the isolation filter is connected to the input end of the second cladding pump stripper, the output end of the second cladding pump stripper is connected to the second double-clad gain fiber, the 90% splitting end of the second combiner is connected to the second double-clad gain fiber, and the pump end of the second combiner is connected to the pulse pump.

[0025] The seed light from the seed source passes through a circulator and is then fed into the first-stage double-clad amplifier. The pump and seed light are then coupled into the first double-clad gain fiber via a first combiner. Excess pump light is filtered out using a first-clad pump stripper fabricated using an etching process. The amplified seed light returns to the gain fiber through a fiber reflector, where it is amplified again and fed into the circulator. The pulses then pass through an isolation filter and are fed into the second-stage double-clad amplifier. After the filter is added, the side-mode suppression ratio of the output pulses exceeds 40 dB, improving the amplification efficiency of the subsequent double-clad pump amplifier. The second-stage double-clad amplifier couples the pump and seed light into the second double-clad gain fiber via a combiner. The second-stage double-clad amplifier employs an inverse amplification structure. Excess pump light is filtered out using a second-clad pump stripper fabricated using an etching process. The amplified seed light is then output through the combiner, achieving an average output power of 1.5 W at a pulse width of 5 ns and a repetition rate of 500 kHz.

[0026] Although the above describes the illustrative specific embodiments of the present invention to facilitate understanding of the present invention by those skilled in the art, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those skilled in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the appended claims, these changes are obvious, and all inventions and creations using the concepts of the present invention are protected.

Claims

1. A laser radar light source based on TO package, characterized by: The laser radar light source includes a seed source, a circulator, a first combiner, a first double-clad gain fiber, a fiber reflector, an isolation filter, a second double-clad gain fiber, a second combiner and a pulse pump source; wherein the seed source adopts a TO-packaged fiber-coupled semiconductor laser; the second combiner divides the pulse pump light output by the pulse pump source into a first pulse pump light and a second pulse pump light, which serve as pump light of the first double-clad gain fiber and the second double-clad gain fiber respectively; the seed light output by the seed source is input through the first port of the circulator and then output to the first combiner through the second port, and the first combiner combines the first pulse pump light with the seed light. The light is coupled into the first double-clad gain fiber, the amplified seed light returns to the first double-clad gain fiber through the fiber reflector and is amplified again before being input into the second port of the circulator. The amplified seed light passes through the third port of the circulator and is output to the isolation filter. The amplified seed light passes through the isolation filter and is input into the second double-clad gain fiber. The second combiner reversely inputs the second pulse pump light into the second double-clad gain fiber. After amplification by the second double-clad gain fiber, the seed light is output through the second combiner. The seed light output by the seed source is a pulse signal, and the power ratio of the first pulse pump light to the second pulse pump light is 1:

9.

2. A TO-packaged laser radar light source according to claim 1, characterized in that: The laser radar light source further includes a first cladding pump stripper disposed between the first double-clad gain fiber and the fiber reflector, and a second cladding pump stripper disposed between the isolation filter and the second double-clad gain fiber.

3. The TO-packaged laser radar light source according to claim 1, characterized in that: The central wavelength of the seed source is 1550±2 nm, the peak power of the output light is 200 mW, the pulse width is adjustable from 0.5 to 250 ns, and the repetition frequency is adjustable from 1 to 1000 kHz.

4. The TO-packaged laser radar light source according to claim 1, characterized in that: The maximum output power of the pulse pump source is 9W, the central wavelength is 915 nm, the pulse width is adjustable from 1 to 500 ns, and the repetition frequency is adjustable from 1 to 3000 kHz.

5. The TO-packaged laser radar light source according to claim 1, characterized in that: The first double-clad gain fiber and the second double-clad gain fiber are both LMA-EYDF-12 / 130 optical fibers, with lengths of 1.5 m and 3 m respectively.

6. A TO-packaged laser radar light source according to any one of claims 1 to 5, characterized in that: The pulse signal of the seed light is triggered by the trailing edge of the pulse of the pulse pump light and is injected into the gain optical fiber when the pulse pump light ends.

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