CN110233413A - A kind of multi-Wavelength Pulses optical fiber laser and laser radar system - Google Patents

Abstract

The embodiment of the invention discloses a multi-wavelength pulse fiber laser and a laser radar system. The multi-wavelength pulsed fiber laser includes a seed light source module, a pump source and at least one level of fiber amplifier module. The pump input ports of all fiber amplifier modules are connected to the pump source, and the output port of the seed light source module is connected to the first stage fiber amplifier module. The input end connection; the seed light source module is used to emit at least two pulsed lasers of different wavelengths, including at least two laser chips, each laser chip is connected to an output optical fiber, and each laser chip emits a pulsed laser of a wavelength, And it is integrated in the seed light source module; the pump source is used to provide energy for the fiber amplifier module; the fiber amplifier module is used to amplify the pulse laser generated by the seed light source module, and output the amplified pulse laser. The technical solution of the embodiment of the present invention can realize multi-wavelength pulse output, and has the advantages of simple structure, small volume, low cost and stable performance.

Description

A multi-wavelength pulsed fiber laser and laser radar system

technical field

Embodiments of the present invention relate to laser technology, in particular to a multi-wavelength pulse fiber laser and a laser radar system.

Background technique

Compared with ordinary light sources, the laser emitted by the laser has many advantages such as good monochromaticity, high brightness, and good directionality, and has been widely used in laser marking, cutting, ranging, communication and other fields.

Lasers are divided into continuous lasers and pulsed lasers in operation. Pulsed laser refers to a laser with a single laser pulse width less than 0.25 seconds and only works once at a certain interval, and it has a relatively large peak power. For example, in the application of communication systems, single-wavelength lasers cannot meet people's needs due to their limited bandwidth. In order to further improve communication bandwidth and capacity, wavelength division multiplexing technology is widely used.

In the application of laser radar, the laser radar of surrounding vehicles emits laser signals with the same wavelength as the vehicle, which is difficult for radar to distinguish. On the same road, if multiple vehicles equipped with laser radars emitting the same wavelength are close to each other, these laser radars may receive light pulses from other radars and determine them as target echoes, which will cause this phenomenon. The station's radar was jammed leading to false detections. Existing lidar generally adopts methods such as reducing the radar field of view angle and reducing the area of the photosensitive array to avoid interference from external light signals. However, such measures are almost ineffective against interference signals from other laser radars with the same wavelength. In order to improve the anti-interference performance of lidar, multi-wavelength pulsed lasers can be used in combination with wavelength division multiplexing technology. The most direct method for the light source of the wavelength division multiplexing system is to use multiple single-wavelength lasers, but simply increasing the number of light sources to meet the needs of increasing the number of channels will inevitably increase the cost and complexity of the system. Therefore, how to obtain stable performance The multi-wavelength laser pulse has become a research hotspot in the current laser field.

Contents of the invention

Embodiments of the present invention provide a multi-wavelength pulse fiber laser and a laser radar system to realize multi-wavelength pulse output, and have the advantages of simple structure, small volume, low cost, and stable performance.

In the first aspect, an embodiment of the present invention provides a multi-wavelength pulsed fiber laser, including:

A seed light source module, a pumping source, and at least one stage of optical fiber amplification modules, the pumping input ends of all the optical fiber amplification modules are connected to the pumping source, and the output ends of the seed light source module are connected to the first stage of the optical fiber The input terminal connection of the amplification module;

The seed light source module is used to emit at least two pulsed lasers with different wavelengths. The seed light source module includes at least two laser chips, each of which is connected to an output optical fiber, and each of the laser chips emits a A pulsed laser with different wavelengths, which is integrally packaged in the seed light source module;

The pump source is used to provide energy for the optical fiber amplification module;

The optical fiber amplification module is used to amplify the pulse laser generated by the seed light source module, and output the amplified pulse laser.

Optionally, at least two stages of optical fiber amplification modules are included; at least two stages of the optical fiber amplification modules are arranged in series.

Optionally, the optical fiber amplification module at the first stage includes a first wavelength division multiplexer, a first optical isolator, a first gain fiber, and a first pump combiner;

The first wavelength division multiplexer includes at least two input ports and one output port, each input port is connected to an output optical fiber of the laser chip, and the output port is connected to the input port of the first optical isolator;

The output end of the first optical isolator is connected to the first input end of the first pumping beam combiner through the first gain fiber; or the output end of the first optical isolator is connected to the first The first input end of the pumping beam combiner is connected, and the output end of the first pumping beam combiner is connected to the first gain fiber;

The second input end of the first pump combiner is connected to the pump source;

The optical fiber amplification module in the last stage includes a second wavelength division multiplexer, a second optical isolator, at least two sections of second gain fibers, at least two second pump combiners, a first beam splitter and at least two A third optical isolator, wherein the second wavelength division multiplexer includes an input end and at least two output ends, the first beam splitter includes an input end and at least two output ends, and the first beam splitter includes an input end and at least two output ends, and the first beam splitter includes an input end and at least two output ends. The number of output ends of the beam splitter, the number of output ends of the second wavelength division multiplexer, the number of the second pump beam combiner, the number of the second gain fiber and the third optical isolator The number is the same as the number of laser chips in the seed light source module;

The input end of the second optical isolator is connected to the output end of the optical fiber amplification module of the previous stage, and the output end of the second optical isolator is connected to the input end of the second wavelength division multiplexer;

The input end of the first beam splitter is connected to the pump source;

The first input end of the second pumping beam combiner is connected to each output end of the second wavelength division multiplexer in a one-to-one correspondence through the second gain fiber, and the second pumping beam combiner The second input end of the first beam splitter is connected to each output end of the first beam splitter in a one-to-one correspondence, and the output end of the second pumping beam combiner is connected to the input end of the third optical isolator; or the The first input end of the second pumping beam combiner is connected to each output end of the second wavelength division multiplexer in a one-to-one correspondence, and the second input end of the second pumping beam combiner is connected to the Each output end of the first beam splitter is connected in one-to-one correspondence, the output end of the second pumping beam combiner is connected to the input end of the second gain fiber, and the output end of the second gain fiber is connected to the input end of the second gain fiber. Connect to the input terminal of the third optical isolator.

Optionally, at least one filter is also included, and the filter is arranged between the optical fiber amplification module of the previous stage and the optical fiber amplification module of the subsequent stage, and the input end of the filter is connected to the optical fiber amplification module of the previous stage. The output end of the optical fiber amplification module is connected, and the output end of the filter is connected with the input end of the optical fiber amplification module in the next stage.

Optionally, the fiber amplification module of the last stage further includes at least two collimators, and each collimator is connected to an output end of the fiber amplification module of the last stage.

Optionally, the first gain fiber and the second gain fiber are doped fibers doped with the same rare earth element.

Optionally, a second beam splitter is also included, the input end of the second beam splitter is connected to the output end of the pump source, the first output end of the second beam splitter is connected to the first The second input end of the pump beam combiner is connected, and the second output end of the second beam splitter is connected with the input end of the first beam splitter.

Optionally, the seed light source module further includes at least two collimating lenses, the collimating lenses correspond to the laser chips one by one, and are arranged between the laser chip and the output optical fiber, and the collimating lenses The lens is used to couple the pulsed laser output from the laser chip into the output optical fiber.

In the second aspect, an embodiment of the present invention further provides a lidar system, including the multi-wavelength pulsed fiber laser described in any one of the first aspects.

Optionally, a light receiving unit and a signal processing unit are also included;

The light receiving unit includes a wavelength division device and a photoelectric detection module arranged at each output end of the wavelength division device;

The wavelength division device includes at least two wavelength division modules, each of which only transmits light of one wavelength and reflects light of other wavelengths to the next wavelength division module.

The multi-wavelength pulsed fiber laser provided by the embodiment of the present invention includes a seed light source module, a pump source, and at least one level of optical fiber amplification modules. It is connected with the input end of the first-stage optical fiber amplification module; the seed light source module is used to emit pulsed laser light of at least two different wavelengths, and the seed light source module includes at least two laser chips, each laser chip is connected with an output optical fiber, each The laser chip emits a pulsed laser with a wavelength, and is packaged in the seed light source module; the pump source is used to provide energy for the fiber amplifier module; the fiber amplifier module is used to amplify the pulse laser generated by the seed light source module, and the amplified Pulse laser output. By encapsulating laser chips that emit pulsed lasers with different wavelengths in the seed light source module, the seed light source module can output at least two pulsed lasers with different wavelengths, and provide pump light for all fiber amplifier modules at the same time through one pump source, which can Simplify the structure of the laser and reduce costs; output at least two wavelengths through a seed light source module to achieve multi-wavelength pulsed laser output, and has the advantages of simple structure, small size, low cost, and stable performance.

Description of drawings

Fig. 1 is a schematic structural diagram of a multi-wavelength pulsed fiber laser provided by an embodiment of the present invention;

Fig. 2 is a schematic diagram of a partial structure of a seed light source module provided by an embodiment of the present invention;

3 is a schematic structural diagram of another multi-wavelength pulsed fiber laser provided by an embodiment of the present invention;

4 to 6 are structural schematic diagrams of yet another multi-wavelength pulsed fiber laser provided by an embodiment of the present invention;

Fig. 7 is a schematic structural diagram of another multi-wavelength pulsed fiber laser provided by an embodiment of the present invention;

Fig. 8 is a schematic structural diagram of another multi-wavelength pulsed fiber laser provided by an embodiment of the present invention;

Fig. 9 is a schematic structural diagram of another multi-wavelength pulsed fiber laser provided by an embodiment of the present invention;

FIG. 10 is a schematic structural diagram of a laser radar system provided by an embodiment of the present invention;

Fig. 11 is a schematic structural diagram of a wavelength division device provided by an embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, only some structures related to the present invention are shown in the drawings but not all structures.

Terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. It should be noted that the orientation words such as "up", "down", "left", and "right" described in the embodiments of the present invention are described from the angles shown in the drawings, and should not be interpreted as a reference to the implementation of the present invention. Example limitations. Also in this context, it also needs to be understood that when it is mentioned that an element is formed "on" or "under" another element, it can not only be directly formed "on" or "under" another element, but also can be formed "on" or "under" another element. Formed "on" or "under" another element indirectly through intervening elements. The terms "first", "second", etc. are used for descriptive purposes only, do not indicate any order, quantity or importance, but are used to distinguish different components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present invention in specific situations.

An embodiment of the present invention provides a multi-wavelength pulsed fiber laser. The multi-wavelength pulsed fiber laser includes: a seed light source module, a pump source, and at least one level of fiber amplification modules. The pump input ends of all fiber amplification modules are connected to the pump source connection, the output end of the seed light source module is connected to the input end of the first-stage optical fiber amplification module; the seed light source module is used to emit at least two pulsed lasers with different wavelengths, and the seed light source module includes at least two laser chips, and each laser chip is connected to the An output optical fiber is connected, each laser chip emits a pulsed laser of a wavelength, and is packaged in the seed light source module; the pump source is used to provide energy for the fiber amplifier module; the fiber amplifier module is used to amplify the output generated by the seed light source module pulse laser, and output the amplified pulse laser.

It can be understood that the seed light source module is used to generate at least two pulsed lasers with different wavelengths, wherein the laser chip can be a semiconductor laser chip, and all laser chips are packaged in the seed light source module. Since the semiconductor material is sensitive to temperature, the specific implementation , the temperature sensor and temperature control device can also be packaged in the seed light source module to improve the output stability of the seed light source module. According to the pulse power to be output, the number of fiber amplifier modules can be selected. For example, when the output power is tens or hundreds of milliwatts, one-stage amplification can be selected, and when the output power is in the order of watts, two-stage amplification can be selected. The pump source can be a multimode semiconductor laser.

Exemplarily, taking a multi-wavelength pulsed fiber laser including a first-stage fiber amplification module and a seed light source module including three laser chips as an example, FIG. 1 is a schematic structural diagram of a multi-wavelength pulsed fiber laser provided by an embodiment of the present invention. Referring to Fig. 1, the multi-wavelength pulsed fiber laser provided in this embodiment includes a seed light source module 1, a pump source 2 and an optical fiber amplification module 3, the pumping input end of the optical fiber amplification module 3 is connected to the pump source 2, and the seed light source module 1 The output end of the optical fiber amplification module 3 is connected to the input end; the seed light source module 1 includes at least three laser chips 11, each laser chip is connected to an output optical fiber 12, and each laser chip 11 sends a pulse laser of a wavelength, And it is integrally packaged in the seed light source module 1; the pump source 2 is used to provide energy for the fiber amplifier module 3; the fiber amplifier module 3 is used to amplify the pulse laser generated by the seed light source module 1 and output the amplified pulse laser.

Optionally, the seed light source module also includes at least two collimating lenses, the collimating lenses correspond to the laser chips one by one, and are arranged between the laser chip and the output optical fiber, and the collimating lenses are used to couple the pulsed laser output from the laser chip into output fiber.

Exemplarily, FIG. 2 is a schematic diagram of a partial structure of a seed light source module provided by an embodiment of the present invention. Referring to FIG. 2 , the seed light source module further includes a collimator lens 13 disposed between the laser chip 11 and the output fiber 12 , and the collimator lens is used to couple pulsed laser light from the output end of the laser chip 11 into the output fiber 12 .

It should be noted that the collimator lens 13 shown in FIG. 2 is a convex lens is only exemplary, and other forms such as a combination of a convex lens and a concave lens may also be used during specific implementation, which is not limited in the present invention.

In the technical solution of this embodiment, by integrally packaging the laser chips that emit pulsed lasers with different wavelengths in the seed light source module, the seed light source module can output at least two pulsed lasers with different wavelengths, and simultaneously amplify all optical fibers through one pump source The module provides pump light, which can simplify the structure of the laser and reduce the cost; output at least two wavelengths through a seed light source module to achieve multi-wavelength pulsed laser output, and has the advantages of simple structure, small size, low cost, and stable performance.

On the basis of the above technical solution, optionally, the multi-wavelength pulsed fiber laser provided by the embodiment of the present invention includes at least two stages of fiber amplification modules; at least two stages of fiber amplification modules are arranged in series.

It is understandable that because the fiber amplification module may be saturated during amplification, single-stage amplification cannot meet the requirements in some application scenarios. Multi-stage amplification modules can be connected in series to increase the output power of laser pulses.

Optionally, the first-stage optical fiber amplification module includes a first wavelength division multiplexer, a first optical isolator, a first gain fiber, and a first pump combiner; the first wavelength division multiplexer includes at least two input end and an output end, each input end is connected with the output optical fiber of a laser chip, and the output end is connected with the input end of the first optical isolator; The output end of the first optical isolator is connected with the first pumping through the first gain optical fiber The first input end of the beam combiner is connected; or the output end of the first optical isolator is connected with the first input end of the first pumping beam combiner, and the output end of the first pumping beam combiner is connected with the first gain fiber The second input end of the first pump beam combiner is connected to the pump source; the optical fiber amplification module of the last stage includes a second wavelength division multiplexer, a second optical isolator, at least two sections of second gain fibers, At least two second pumping beam combiners, a first beam splitter and at least two third optical isolators, wherein the second wavelength division multiplexer includes an input terminal and at least two output terminals, and the first beam splitter Including one input port and at least two output ports, the number of output ports of the first beam splitter, the number of output ports of the second wavelength division multiplexer, the number of second pump beam combiners, the number of second gain fibers and The number of the third optical isolator is the same as the number of laser chips in the seed light source module; the input end of the second optical isolator is connected with the output end of the previous stage optical fiber amplification module, and the output end of the second optical isolator is connected with the second optical isolator The input end of the wavelength division multiplexer is connected; the input end of the first beam splitter is connected with the pump source; the first input end of the second pump beam combiner is connected to the second wavelength division multiplexer through the second gain fiber Each output end is connected in one-to-one correspondence, the second input end of the second pumping beam combiner is connected in one-to-one correspondence with each output end of the first beam splitter, the output end of the second pumping beam combiner is connected to the third The input end of the optical isolator is connected; or the first input end of the second pumping beam combiner is connected to each output end of the second wavelength division multiplexer in one-to-one correspondence, and the second input end of the second pumping beam combiner The output end of the second pumping beam combiner is connected to the input end of the second gain fiber, and the output end of the second gain fiber is connected to the third optical isolator input connection.

Exemplarily, the multi-wavelength pulsed fiber laser includes a two-stage fiber amplification module and the seed light source module includes three laser chips as an example. Figure 3 shows the structure of a multi-wavelength pulsed fiber laser provided by an embodiment of the present invention schematic diagram. Referring to Fig. 3, the multi-wavelength pulsed fiber laser provided by this embodiment includes a first-stage fiber amplification module 2a and a second-stage fiber amplification module 2b, and the first-stage fiber amplification module 2a includes a first wavelength division multiplexer 21a, a first Optical isolator 22a, the first gain fiber 23a and the first pump beam combiner 24a; 12 connections, the output end is connected with the input end of the first optical isolator 22a; the output end of the first optical isolator 22a is connected with the first input end of the first pumping beam combiner 24a through the first gain fiber 23a; the second The first-stage optical fiber amplification module 2b includes a second wavelength division multiplexer 21b, a second optical isolator 22b, three sections of second gain fibers 23b, three second pumping beam combiners 24b, a first beam splitter 25b and three The third optical isolator 26b, wherein the second wavelength division multiplexer 21b includes an input port and three output ports, and the first beam splitter 25b includes an input port and three output ports; the input of the second optical isolator 22b end is connected with the output end of the first stage optical fiber amplification module 2a, the output end of the second optical isolator 22b is connected with the input end of the second wavelength division multiplexer 21b; the input end of the first beam splitter 25b is connected with the pumping source 3 connections; the first input end of the second pumping beam combiner 24b is connected to each output end of the second wavelength division multiplexer 21b one by one through the second gain fiber 23b, and the second pumping beam combiner 24b The second input terminal is connected to each output terminal of the first beam splitter 25b in a one-to-one correspondence, and the output terminal of the second pumping beam combiner 24b is connected to the input terminal of the third optical isolator 26b.

It can be understood that the first optical fiber amplification module and the second optical fiber amplification module shown in Fig. 3 both adopt the reverse pumping mode, and in other embodiments, both the first optical fiber amplification module and the second optical fiber amplification module can be selected Forward pumping or reverse pumping, for example, FIG. 4 to FIG. 6 are schematic structural diagrams of yet another multi-wavelength pulsed fiber laser provided by an embodiment of the present invention. Referring to Fig. 4, different from Fig. 3, the output end of the first optical isolator 22a is connected with the first input end of the first pumping beam combiner 24a, and the output end of the first pumping beam combiner 24a is connected with the first The gain fiber 23a is connected, and the second input end of the first pump combiner 24a is connected to the pump source 3, that is, the first optical fiber amplification module adopts a forward pumping mode. Referring to Fig. 5, different from Fig. 3, the first input end of the second pumping beam combiner 24b is connected to each output end of the second wavelength division multiplexer 21b in one-to-one correspondence, and the second pumping beam combiner The second input end of 24b is connected to each output end of the first beam splitter 25b in one-to-one correspondence, and the output end of the second pumping beam combiner 24b is connected to the input end of the second gain fiber 23b, and the second gain fiber 23b The output end of the optical fiber is connected to the input end of the third optical isolator 26b, that is, the second optical fiber amplification module adopts a forward pumping mode. Referring to Fig. 6, different from Fig. 3, the output end of the first optical isolator 22a is connected with the first input end of the first pumping beam combiner 24a, and the output end of the first pumping beam combiner 24a is connected with the first The gain fiber 23a is connected, and the second input end of the first pumping beam combiner 24a is connected with the pumping source 3; the first input end of the second pumping beam combiner 24b is connected with each of the second wavelength division multiplexer 21b The output ends are connected in one-to-one correspondence, and the second input end of the second pumping beam combiner 24b is connected in one-to-one correspondence with each output end of the first beam splitter 25b, and the output end of the second pumping beam combiner 24b is connected to the first beam combiner 25b. The input end of the second gain fiber 23b is connected, and the output end of the second gain fiber 23b is connected to the input end of the third optical isolator 26b, that is, both the first fiber amplifier module and the second fiber amplifier module adopt forward pumping mode. It can be flexibly selected according to needs during specific implementation.

It should be noted that Fig. 3 to Fig. 6 are only exemplary embodiments. During specific implementation, the position of each device can be adjusted according to the actual situation. For example, the position of the isolator can be moved. The connection sequence of each device in the embodiment of the present invention It is not limited, and it only needs to meet the conditions of the optical fiber amplifier.

Optionally, the multi-wavelength pulsed fiber laser provided by the embodiment of the present invention also includes at least one filter, the filter is arranged between the previous stage fiber amplification module and the subsequent stage fiber amplification module, the input end of the filter is connected to the previous stage The output end of the first-stage optical fiber amplification module is connected, and the output end of the filter is connected with the input end of the next-stage optical fiber amplification module.

Exemplarily, FIG. 7 is a schematic structural diagram of another multi-wavelength pulsed fiber laser provided by an embodiment of the present invention. With reference to Fig. 7, the multi-wavelength pulsed fiber laser provided by this embodiment also includes a filter 4, the filter 4 is arranged between the first-stage fiber amplifier module 2a and the second-stage fiber amplifier module 2b, and the input end of the filter 4 It is connected to the output end of the first-stage optical fiber amplification module 2a, and the output end of the filter 4 is connected to the input end of the second-stage optical fiber amplification module 2b.

It can be understood that the filter 4 only allows the light of the wavelength emitted by the seed light source module 1 to pass through, and prevents the light of other wavelengths from passing through (such as the spontaneous radiation of the first optical fiber amplification module 2a), thereby filtering out noise and improving Laser stability.

Optionally, the last-stage optical fiber amplification module further includes at least two collimators, and each collimator is connected to an output end of the last-stage optical fiber amplification module.

Exemplarily, FIG. 8 is a schematic structural diagram of another multi-wavelength pulsed fiber laser provided by an embodiment of the present invention. Referring to FIG. 8 , the second-stage optical fiber amplification module 2b further includes three collimators 27b, and each collimator 27b is connected to an output end of the second-stage optical fiber amplification module 2b. Through the setting of the collimator, the beam quality of the output light of the laser can be improved, so that it can be applied to more scenes.

Optionally, the first gain fiber and the second gain fiber are doped fibers doped with the same rare earth element.

Optionally, the doped fiber includes any one of ytterbium-doped fiber, erbium-doped fiber, double-clad erbium-ytterbium co-doped fiber, and thulium-doped fiber.

It can be understood that ytterbium-doped fiber can be used to generate laser in the 1060nm band, erbium-doped fiber and double-clad erbium-ytterbium co-doped fiber can be used to generate laser in the 1550nm band, and thulium-doped fiber can be used to generate laser in the 2000nm band. The specific implementation can be selected according to the actual application scenario, and use wavelength-matched laser chips and filters.

Exemplarily, the 1550nm waveband is located in the third low-loss communication window. Lasers in this waveband have strong penetrating power to clouds and smoke, and the damage threshold of the human eye in the 1550nm waveband is four times higher than that in the 1060nm waveband. order of magnitude, so this laser band is also called "eye-safe" laser band. Since common erbium-doped 1550nm pulsed fiber lasers may have the problem of low power, the embodiment of the present invention can also use erbium-ytterbium co-doped double-clad fibers to effectively increase the output power of the laser. Using erbium-ytterbium co-doped fiber, the high-concentration Yb ³⁺ doping can play a good role in isolating the adjacent Er ³⁺ , thereby significantly reducing the concentration quenching effect of Er ³⁺ and reducing the difference between Er ³⁺ The probability of up-conversion occurs during the interval, effectively improving the gain and output power.

FIG. 9 is a schematic structural diagram of another multi-wavelength pulsed fiber laser provided by an embodiment of the present invention. Referring to Fig. 9, optionally, the multi-wavelength pulsed fiber laser provided in this embodiment also includes a second beam splitter 5, the input end of the second beam splitter 5 is connected to the output end of the pumping source 3, and the second beam splitter The first output end of the pump is connected to the second input end of the first pump beam combiner 24a, and the second output end of the second beam splitter 5 is connected to the input end of the first beam splitter 25b.

During specific implementation, the light splitting ratio of the two output ends of the second beam splitter 5 can be reasonably designed. It can be understood that the ratio of the pump light power of the first-stage optical fiber amplification module 2a and the second-stage optical fiber amplification module 2b is mainly Depending on the absorption efficiency of the doped fiber and the output optical power value, for example, the output optical power is 1W, then the ratio of the pump optical power of the first stage and the second stage can generally be 2:8 or 3:7. In this embodiment, the two-stage pump light power ratio can be set between 2:8 and 4:6.

Optionally, the pump source includes any one of a 915nm multimode semiconductor laser, a 940nm multimode semiconductor laser or a 976nm multimode semiconductor laser with a bulk grating.

Exemplarily, for the erbium-ytterbium co-doped double-clad fiber, since the absorption spectrum of Yb ³⁺ is very wide (800nm-1000nm), the absorption bandwidth in the 915nm and 940nm bands is very wide, ensuring that factors such as temperature cause the wavelength drift of the pump source It will not have a significant impact on the amplifier. The 976nm laser with a volume grating (VBG) can ensure that the wavelength is locked at 976nm, and it hardly drifts with temperature. At the ambient temperature of -35°C to 65°C, its wavelength drift is about 0.1nm. Therefore, the absorption efficiency of the amplification system for the pump light can be improved, and the requirement for the wavelength of the pump laser is also reduced.

An embodiment of the present invention also provides a laser radar system, including any one of the multi-wavelength pulsed fiber lasers provided in the above embodiments. In actual implementation, both the seed light source module and the pump source need a driving circuit, and the driving circuit can be controlled by a Field Programmable Gate Array (Field Programmable Gate Array, FPGA). The pulse width of the seed source is 3ns~5ns, and the power is 10mW~ 20mW. By using the multi-wavelength pulsed fiber laser provided by the embodiment of the present invention, the anti-interference performance of the laser radar system can be improved.

Optionally, the laser radar system provided by the embodiment of the present invention also includes a light receiving unit and a signal processing unit; the light receiving unit includes a wavelength division device and a photoelectric detection module arranged at each output end of the wavelength division device; the wavelength division device includes at least two A wavelength division module, each wavelength division module only transmits light of one wavelength, and reflects light of other wavelengths to the next wavelength division module.

Exemplarily, FIG. 10 is a schematic structural diagram of a lidar system provided by an embodiment of the present invention. Referring to Fig. 10, the lidar system provided by this embodiment includes a light emitting unit 10, a light receiving unit 20 and a signal processing unit 30, wherein the light emitting unit 10 includes any one of the multi-wavelength pulsed fiber lasers provided in the above embodiments, and the light receiving unit The unit 20 includes a wavelength division device and photodetection modules arranged at each output end of the wavelength division device. FIG. 11 is a schematic structural diagram of a wavelength division device provided by an embodiment of the present invention. With reference to Fig. 11, the wavelength division device comprises at least two wavelength division modules 100 (three wavelength division modules are schematically shown in Fig. 11), each wavelength division module only transmits the light of a kind of wavelength, and reflects the light of other wavelengths To the next wavelength division module (for example, the optical wavelength division module with a transmission wavelength of λ1 reflects light with wavelengths of _λ2 and _λ3 ), and so _on . In an embodiment, each wavelength division module is inclined at a certain angle, such as about 1-2°. It can be understood that the inclination angle of each wavelength division module can also be determined according to the relative positional relationship among the wavelength division modules.

The wavelength division device provided in this embodiment adopts a free-space filtering method, which is lower in cost than a wavelength division multiplexer of a traditional optical fiber device, and is beneficial to reduce the cost of a laser radar system.

Note that the above are only preferred embodiments of the present invention and applied technical principles. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the protection scope of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and can also include more other equivalent embodiments without departing from the concept of the present invention, and the present invention The scope is determined by the scope of the appended claims.

Claims (10)

1. a kind of multi-Wavelength Pulses optical fiber laser characterized by comprising

The pumping of seed light source module, pumping source and at least one level optic fiber amplifying module, all optic fiber amplifying modules is defeated Enter end to connect with the pumping source, the input of optic fiber amplifying module described in the output end and the first order of the seed light source module End connection；

The seed light source module is used to issue the pulse laser of at least two different wave lengths, and the seed light source module includes extremely Few two laser chips, each laser chip are connect with an output optical fibre, and each laser chip issues a kind of wave Long pulse laser, and integral packaging is in the seed light source module；

The pumping source is used to provide energy for the optic fiber amplifying module；

The optic fiber amplifying module is used to amplify the pulse laser that the seed light source module generates, and amplified pulse is swashed Light output.

2. multi-Wavelength Pulses optical fiber laser according to claim 1, which is characterized in that including at least two-stage fiber amplifier Module；At least optic fiber amplifying module described in two-stage is arranged in series.

3. multi-Wavelength Pulses optical fiber laser according to claim 2, which is characterized in that fiber amplifier mould described in the first order Block includes the first wavelength division multiplexer, the first optoisolator, the first gain fibre and the first pump combiner；

First wavelength division multiplexer includes at least two input terminals and an output end, each input terminal and the laser The output optical fibre of chip connects, and output end is connect with the input terminal of first optoisolator；

The output end of first optoisolator is first defeated by first gain fibre and first pump combiner Enter end connection；Or the output end of first optoisolator is connect with the first input end of first pump combiner, institute The output end for stating the first pump combiner is connect with first gain fibre；

Second input terminal of first pump combiner is connect with the pumping source；

Optic fiber amplifying module described in afterbody includes the second wavelength division multiplexer, the second optoisolator, at least two section of second gain Optical fiber, at least two second pump combiners, the first beam splitter and at least two third optoisolators, wherein second wavelength-division Multiplexer includes an input terminal and at least two output ends, and first beam splitter includes that an input terminal and at least two are defeated Outlet, the output end quantity of first beam splitter, the quantity of the output end of second wavelength division multiplexer, second pumping The quantity of the quantity of bundling device, the quantity of second gain fibre and the third optoisolator with the seed light source mould The quantity of laser chip is identical in block；

The output end of optic fiber amplifying module described in the input terminal and previous stage of second optoisolator connects, second light every It is connect from the output end of device with the input terminal of second wavelength division multiplexer；

The input terminal of first beam splitter is connect with the pumping source；

The first input end of second pump combiner passes through second gain fibre and second wavelength division multiplexer Each output end connects one to one, and each of the second input terminal of second pump combiner and first beam splitter are defeated Outlet connects one to one, and the output end of second pump combiner is connect with the input terminal of the third optoisolator；Or Each output end of the first input end of second pump combiner described in person and second wavelength division multiplexer connects one to one, Second input terminal of second pump combiner and each output end of first beam splitter connect one to one, and described The output end of two pump combiners is connect with the input terminal of second gain fibre, the output end of second gain fibre with The input terminal of the third optoisolator connects.

4. multi-Wavelength Pulses optical fiber laser according to claim 3, which is characterized in that further include at least one filtering Device, the filter are set between optic fiber amplifying module described in optic fiber amplifying module and rear stage described in previous stage, the filter The output end of optic fiber amplifying module described in the input terminal and previous stage of wave device connects, the output end of the filter and rear stage institute State the input terminal connection of optic fiber amplifying module.

5. multi-Wavelength Pulses optical fiber laser according to claim 3, which is characterized in that fiber amplifier described in afterbody Module further includes at least two collimators, an output end of optic fiber amplifying module described in each collimator and afterbody Connection.

6. multi-Wavelength Pulses optical fiber laser according to claim 3, which is characterized in that first gain fibre and institute Stating the second gain fibre is the doped fiber for adulterating identical rare earth element.

7. multi-Wavelength Pulses optical fiber laser according to claim 3, which is characterized in that further include the second beam splitter, institute The input terminal for stating the second beam splitter is connect with the output end of the pumping source, the first output end of second beam splitter with it is described Second input terminal of the first pump combiner connects, and the second output terminal of second beam splitter is defeated with first beam splitter Enter end connection.

8. multi-Wavelength Pulses optical fiber laser according to claim 1, which is characterized in that the seed light source module is also wrapped At least two collimation lenses are included, the collimation lens and the laser chip correspond, and are set to the laser chip and institute It states between output optical fibre, the collimation lens is used to the pulse laser that the laser chip exports being coupled into the output light It is fine.

9. a kind of laser radar system, which is characterized in that swash including any multi-Wavelength Pulses optical fiber of claim 1~8 Light device.

10. laser radar system according to claim 9, which is characterized in that further include light receiving unit and signal processing Unit；

The light receiving unit includes a wavelength-division device and the photoelectric detection module for being set to each output end of wavelength-division device；

The wavelength-division device includes at least two wavelength division modules, and each wavelength division module only transmits a kind of light of wavelength, and will The light of other wavelength reflexes to next wavelength division module.