Main oscillation amplification module, fiber laser system and laser radar

Abstract

The utility model provides a main oscillation amplification module for a laser radar, an optical fiber laser system and the laser radar. The main oscillation amplification module comprises: a housing; the pumping chip is arranged in the shell and is used for providing first light energy with a first wavelength, and the first light energy is transmitted along an optical path; the first optical element group is arranged in the shell and is used for preprocessing the first light energy; the gain optical fiber collimator is coupled with the gain optical fiber and is used for coupling the preprocessed first light energy to the gain optical fiber; and the dichroscope is arranged on an optical path between the first optical element group and the gain optical fiber collimator and is used for guiding the preprocessed first light energy to the gain optical fiber collimator. Separated optical devices are coupled and integrated into the shell, so that the integration level and the stability of the system are improved. In addition, the use of the dichroscope shortens the length of the optical fiber required by the system, reduces the fusion points of the optical fiber, and improves the manufacturability.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of laser radar, and in particular to a master oscillator power amplifier module for laser radar, a fiber laser system and a laser radar. BACKGROUND

[0002] The fiber laser is the light source of the vehicle-mounted laser radar, and its performance directly affects the key indicators such as ranging performance, accuracy, cost and reliability of the laser radar. At present, the scheme of fusing discrete devices with optical fibers is widely used in the market, but there are many problems. First, the manufacturing process is complex, involving multiple precise steps, which increases the production difficulty and reduces the efficiency. Second, the degree of automation is low, requiring a large amount of manual intervention, resulting in high cost and unstable production process. In addition, the complex process and low degree of automation make it difficult to mass-produce the product. The connection between the discrete devices and the optical fiber is prone to failure, affecting the stability and service life of the laser radar.

[0003] The methods described in this section can not necessarily be the methods that have been previously conceived or employed. Unless otherwise indicated, it should not be assumed that any method described in this section can not have been previously conceived or employed. Similarly, it should not be assumed that any problem mentioned in this section has been previously recognized in the art. CONTENT OF THE UTILITY MODEL

[0004] The present disclosure aims to solve at least one of the technical problems existing in the background art. To this end, the purpose of the present disclosure is to provide a master oscillator power amplifier module for laser radar, a fiber laser system and a laser radar, thereby improving the integration and stability, reducing the optical fiber fusion points, improving the manufacturability and reducing the cost.

[0005] According to a first aspect of the embodiments of the present disclosure, a master oscillator power amplifier module for laser radar is provided. The master oscillator power amplifier module comprises: a housing; a pump chip arranged in the housing, configured to provide first light energy having a first wavelength, wherein the first light energy will propagate along an optical path; a first optical element group arranged in the housing, configured to pre-process the first light energy; a gain fiber collimator coupled with a gain fiber, configured to couple the pre-processed first light energy to the gain fiber; and a dichroic mirror arranged on the optical path between the first optical element group and the gain fiber collimator, configured to direct the pre-processed first light energy to the gain fiber collimator.

[0006] According to a second aspect of the embodiments of the present disclosure, a fiber laser system is provided. The fiber laser system comprises: the master oscillator power amplifier module according to the above-mentioned first aspect; a seed light chip arranged in the housing of the master oscillator power amplifier module, configured to provide seed light pulses; and a seed light collimator coupled with the gain fiber, configured to couple the seed light pulses to the gain fiber.

[0007] According to a third aspect of the embodiments of the present disclosure, a fiber laser system is provided. The fiber laser system comprises: the master oscillator power amplifier module according to the first aspect above; a seed light module arranged outside the housing of the master oscillator power amplifier module, configured to provide seed light pulses; and a seed light collimator coupled with the gain fiber, configured to couple the seed light pulses to the gain fiber.

[0008] According to a fourth aspect of the embodiments of the present disclosure, a lidar is provided. The lidar comprises: the fiber laser system according to the second aspect above or according to the third aspect above.

[0009] According to one or more embodiments of the present disclosure, a master oscillator power amplifier module, a fiber laser system and a lidar for lidar are provided. By coupling the originally separated optical devices into the housing, the integration and stability of the system are improved. In addition, the master oscillator power amplifier module according to the embodiments of the present disclosure uses a dichroic mirror to replace the beam combiner and the beam splitter of the fiber laser in the related art, greatly shortening the required fiber length, reducing the fiber fusion points and improving the manufacturability. BRIEF DESCRIPTION OF DRAWINGS

[0010] The accompanying drawings, which are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification, illustrate embodiments and together with the description serve to explain exemplary implementations of the embodiments. The illustrated embodiments are merely examples and do not limit the scope of the claims. In all the drawings, like reference numerals refer to like elements or similar elements but not necessarily identical elements.

[0011] Figure 1 A schematic diagram of a master oscillator power amplifier module for lidar in the related art is shown;

[0012] Figure 2 A schematic diagram of a master oscillator power amplifier module for lidar according to an embodiment of the present disclosure is shown;

[0013] Figure 3 A schematic diagram of a master oscillator power amplifier module for lidar according to an embodiment of the present disclosure is shown; and

[0014] Figure 4 A schematic diagram of a master oscillator power amplifier module for lidar according to an embodiment of the present disclosure is shown.

[0015] Legend of reference signs:

[0016] 10 master oscillator power amplifier module, 20 gain fiber;

[0017] 100 housing, 200 pump chip, 400 gain fiber collimator, 500 dichroic mirror;

[0018] 300 first optical element group, 320 fast axis collimator, 340 slow axis collimator, 360 first mirror;

[0019] 600 second optical element group, 610 beam splitter, 620 isolator, 630 second mirror, 640 third sub light pulse collimator, 650 fourth sub light pulse collimator;

[0020] 720 seed light chip, 740 seed light collimator. DETAILED DESCRIPTION

[0021] The present disclosure will be further described by way of illustration with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the present disclosure and are not intended to limit the present disclosure. In addition, it should be noted that only parts related to the present disclosure are shown in the drawings for ease of description.

[0022] It should be noted that the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict. Unless the number of elements is specifically limited, the element can be one or more. In addition, the numbering of the steps or functional modules used in the present disclosure is only used to identify the respective steps or functional modules, and does not limit the execution order of the respective steps or the connection relationship between the respective functional modules.

[0023] In the present disclosure, the use of the terms "first", "second", and the like to describe various elements is not intended to limit the positional relationship, time sequence relationship, or importance relationship of these elements. Such terms are only used to distinguish one element from another. In some examples, the first element and the second element can refer to the same instance of the element, and in some cases, based on the context of the description, they can also refer to different instances.

[0024] In the present disclosure, the terms used in the description of various described examples are only for the purpose of describing the specific examples, and are not intended to be limiting. Unless the number of elements is specifically limited, the element can be one or more. In addition, the term "and / or" used in the present disclosure covers any one of the listed items and all possible combinations.

[0025] As the core light source of vehicle-mounted laser radar, the performance of the fiber laser determines the ranging performance, ranging accuracy, cost and reliability of the laser radar to a great extent. Most of the fiber lasers used in the market currently adopt a scheme of fusing discrete devices with optical fibers. This scheme has many problems. First, the manufacturing process is relatively complex, requiring precise operation in multiple steps, which not only increases the production difficulty, but also makes it difficult to improve the production efficiency. Second, the degree of automation is low, and a large amount of manual intervention is required in the production process, which not only increases the labor cost, but also makes it difficult to guarantee the stability and consistency of the production process. In addition, due to the complex process and low degree of automation, the cost of the product is high, making it difficult to achieve large-scale batch production. At the same time, the connection between the discrete devices and the optical fiber is prone to failure, which affects the stability and service life of the laser radar. These problems have been restricting the widespread application of fiber lasers in the field of vehicle-mounted laser radars. Therefore, how to improve the optical arrangement of the fiber laser system, especially the master oscillator power amplifier module, to improve the integration and stability of the system, reduce the optical fiber fusion points, improve the manufacturability and reduce the cost, is a technical problem to be solved in this field at present.

[0026] Therefore, according to a first aspect of embodiments of the present disclosure, a master oscillator power amplifier module for a laser radar is provided. By spatial light path coupling, the originally separated optical devices are coupled and integrated into the housing, improving the integration and stability of the system. In addition, the master oscillator power amplifier module according to the embodiments of the present disclosure uses a dichroic mirror to replace the beam combiner and beam splitter of the fiber laser in the related art, greatly shortening the required fiber length, reducing the optical fiber fusion points and improving the manufacturability.

[0027] Figure 2 And Figure 3 A schematic diagram of a master oscillator power amplifier module 10 according to an embodiment of the present disclosure is shown.

[0028] The master oscillator power amplifier module 10 includes a housing 100, a pump chip 200 disposed in the housing 100 for providing first light energy having a first wavelength, wherein the first light energy will propagate along an optical path, a first optical element group 300 disposed in the housing 100 for preprocessing the first light energy, a gain fiber collimator 400 coupled with a gain fiber 20 for coupling the preprocessed first light energy to the gain fiber 20, and a dichroic mirror 500 disposed on the optical path between the first optical element group 300 and the gain fiber collimator 400 for directing the preprocessed first light energy to the gain fiber collimator 400.

[0029] In some embodiments, the pump chip 200 may be a semiconductor laser pump chip, such as a GaAs-based semiconductor laser, an InP-based semiconductor laser, etc. The pump chip 200 may be fixed to the housing 100 by a process such as thermal deposition (e.g., a ceramic heat sink). The pump chip 200 includes a pump pin connected to an external driving circuit, which can provide a first optical energy with a first wavelength as pump light for the fiber laser system. This first optical energy may, for example, travel along a path such as... Figure 2 The optical path is indicated by a solid line with an arrow. The first optical energy can take various forms, such as continuous light, pulsed light, or quasi-continuous wave, depending on the design and application requirements, and no restrictions are imposed here. The wavelength of the first optical energy matches the absorption spectrum of the gain medium in the gain fiber. The energy provided by the pump chip can amplify the seed light in the gain fiber to obtain a laser output with the desired power.

[0030] In some embodiments, the module 10 may further include a first optical element group 300 disposed in the housing 100 for preprocessing the first optical energy. The first optical element group 300 may include at least one of a fast-axis collimator 320 and a slow-axis collimator 340. Figure 2 and Figure 3 The first optical element group 300 shown includes a fast-axis collimator 320 and a slow-axis collimator 340. As an example, the first light energy generated by the pump chip 200 passes through the fast-axis collimator 320 and the slow-axis collimator 340 respectively, thereby adjusting the size, shape or divergence angle of the light spot, so that more pump light energy can pass through the gain fiber collimator 400 and be absorbed by the gain fiber.

[0031] In some embodiments, the gain fiber collimator 400 may be an integral collimator or a combination of a separate fiber ferrule and a lens. The gain fiber collimator 400 can be configured to collect diverging light pulses and generate more parallel beams with reduced or minimal divergence. The lens combined with the separate fiber ferrule may be, for example, a single plano-convex lens or a lens group. In lidar applications, good laser beam quality is crucial. Collimators according to embodiments of this disclosure can be configured to achieve desired characteristics, such as beam diameter, divergence, numerical aperture, focal length, etc. Beam propagation ratio or beam quality factor (also known as M) is commonly used in the art. 2 The quality of a laser beam is measured by a factor (M). 2 The factor represents the degree of variation of the beam relative to an ideal Gaussian beam. M 2 The factor thus reflects how well a collimated beam can be focused, or how well a diverging beam can be collimated. The collimator according to embodiments of this disclosure can also be configured, for example, to meet the scanning resolution requirements of a lidar system while maintaining the desired M...2 factor.

[0032] Continue to refer to Figure 2 and Figure 3 According to embodiments of this disclosure, a dichroic mirror 500 is also provided between the first optical element group 300 and the gain fiber collimator 400 for guiding the pre-processed first optical energy to the gain fiber collimator 400.

[0033] As mentioned above, the master oscillation amplification module according to the embodiments of this disclosure uses a dichroic mirror to replace the beam combiner and beam splitter of the fiber laser in the related art. Figure 1 A schematic diagram of a fiber laser system in the related art is shown.

[0034] Figure 1 The bundler shown typically uses fiber optic precision fusion splicing technology to couple the optical energy from multiple input fibers into a single output fiber. During fabrication, the input fibers are first bundled, then fused tapered to form a fused tapered fiber bundle, which is finally fused to the output fiber. Figure 1 The beam splitter shown typically uses fused taper to form a tapered structure, which is then fused with multiple output fibers. It is evident that fiber lasers in related technologies heavily utilize fiber connections, resulting in a generally long fiber length throughout the system. Furthermore, fiber fusion splices are prone to failure. For example, improper fiber cutting (e.g., tilted end faces or burrs) during splicing can lead to bubbles or cracks at the splice point. Uneven fiber cut surfaces or improper force applied during fusion splicing can also result in insufficient mechanical strength at the splice.

[0035] The main oscillation amplification module according to embodiments of this disclosure can at least partially solve the above-mentioned problems. In some embodiments, depending on specific wavelength selectivity requirements, the dichroic mirror can be coated to achieve effective separation and guidance of the pump light and signal light. (Continue to refer to...) Figure 2 and Figure 3 The first optical energy can be pump light with a wavelength of 940 nm. After passing through the fast-axis collimator 320 and the slow-axis collimator 340, the pre-processed first optical energy is redirected by the guidance of the first mirror 360. Figure 2 and Figure 3 In the optical path arrangement shown, by controlling the thickness and refractive index of the film during the design phase, the dichroic mirror 500 can be specifically set to have high reflectivity at 940nm, so that the first optical energy can be redirected again and coupled to the gain fiber 20 via the gain fiber collimator 400.

[0036] By the dichroic mirror in the master oscillator power amplifier module, the fiber length required by the fiber laser system can be significantly shortened, and the fiber fusion points are reduced and the manufacturability is improved.

[0037] In some embodiments, the master oscillator power amplifier module 10 further includes a second optical element group 600 disposed in the housing 100, the second optical element group 600 configured to receive a second light pulse having a second wavelength different from the first wavelength, the second light pulse being emitted from the gain fiber 20 and directed via the dichroic mirror 500.

[0038] In some embodiments, referring to Figure 3 The second light pulse can be a signal light amplified in the gain fiber 20. Taking an example that the second light pulse has a wavelength of 1550 nm, in addition to being configured to have high reflectivity at 940 nm, the dichroic mirror 500 can be further configured to have high transmissivity at 1550 nm, thereby separating the second light pulse from the first light energy and directing the second light pulse to be transmitted toward the second optical element group 600. It should be understood that the description herein for the specific configuration of the dichroic mirror is only exemplary, and other configurations are also possible depending on the specific optical path design.

[0039] In some embodiments, the second optical element group 600 can include a beam splitter 610, an isolator 620 disposed between the beam splitter 610 and the dichroic mirror 500, a second mirror 630, a third sub-light pulse collimator 640, and a fourth sub-light pulse collimator 650.

[0040] In some embodiments, the isolator 620 is configured to provide unidirectional transmission of the second light pulse. In Figure 3 In the illustrated embodiment, the isolator 620 only allows the second light pulse to be transmitted from the dichroic mirror 500 toward the beam splitter 610, and prevents light transmission in the opposite direction. After the second light pulse reaches the beam splitter 610, it is split into a third sub-light pulse and a fourth sub-light pulse. In Figure 3In the illustrated embodiment, the beam splitter 610 can be configured to allow the third sub-pulse (e.g., more than 99% of the light pulse) to be directly transmitted through the beam splitter 610 into the third sub-pulse collimator 640 to be coupled to the main output fiber. The fourth sub-pulse (e.g., less than 1% of the light pulse) is redirected by the beam splitter 610 and directed via the second mirror 630 to the fourth sub-pulse collimator 650 to be coupled to the reference light fiber. It is noted that similar to the gain fiber collimator 400, the third sub-pulse collimator 640 and the fourth sub-pulse collimator 650 can also be an integrated collimator or a combination of separate fiber ferrule and lens, and can be configured to meet the scanning resolution requirement of, for example, a lidar while maintaining the desired M 2 factors, which are not repeated here.

[0041] In some embodiments, the housing of the master oscillator power amplifier module 10 can further include a bottom shell and a side wall. The pump chip 200, the first optical element group 300, the dichroic mirror 500, and optionally the beam splitter 610, the isolator 620, and the second mirror 630 can be disposed on the bottom shell. The pump chip 200 can be soldered to the bottom shell via a ceramic heat sink or bonded to the bottom shell via conductive glue, and the first optical element group 300, the dichroic mirror 500, and optionally the beam splitter 610, the isolator 620, and the second mirror 630 can be bonded to the bottom shell via conductive glue.

[0042] In some embodiments, the gain fiber collimator 400 and optionally the third sub-pulse collimator 640 and the fourth sub-pulse collimator 650 can be disposed on the side wall of the housing, for example, the gain fiber collimator 400 can be embedded in a first side wall of the housing and the third sub-pulse collimator 640 and the fourth sub-pulse collimator 650 can be embedded in a second side wall opposite to the first side wall. Thus, the dichroic mirror 500 can direct the first light energy into the gain fiber collimator 400 embedded in the first side wall of the housing, and then the first light energy can be coupled to the gain fiber.

[0043] In some embodiments, the gain fiber collimator 400 can also be disposed on the outer side of the first side wall of the housing (not shown in the figure), and the third sub light pulse collimator 640 and the fourth sub light pulse collimator 650 can also be disposed on the outer side of the second side wall opposite to the first side wall (not shown in the figure). In this example, light windows can also be formed on the respective side walls of the housing. For example, a first light window can be formed on the first side wall, via which the dichroic mirror 500 can direct the first light energy to the gain fiber collimator 400 disposed at the corresponding position on the outer side of the housing. A third light window and a fourth light window can be formed on the second side wall, wherein via the third light window, the beam splitter 610 can direct the third sub light pulse to the third sub light pulse collimator 640, and via the fourth light window, the second mirror 630 can direct the fourth sub light pulse to the fourth sub light pulse collimator 650.

[0044] In some embodiments, the housing can be made of metal. The metal housing can provide higher mechanical stability, while having better thermal conductivity and low thermal expansion coefficient, which can effectively dissipate heat and maintain the relative position of the optical elements stable.

[0045] In some embodiments, the housing can also include a cover (not shown in the figure), which can be fused at high temperature to achieve airtight sealing of the housing, thereby better protecting the optical elements inside the housing.

[0046] In some embodiments, the housing can also not include side walls and a cover. For example, the optical devices in the module 10 can be disposed on a bottom plate, and the pump chip is separately packaged, thereby further reducing the volume of the master oscillator power amplifier module.

[0047] According to a second aspect of the embodiments of the present disclosure, a fiber laser system is provided. Figure 4 A schematic diagram of a fiber laser system according to an embodiment of the present disclosure is shown, which is similar to Figure 2 and Figure 3 The difference between the embodiments shown is that the master oscillator power amplifier module 10 further includes a seed light chip 720 and a seed light collimator 740, thereby realizing full integration of the pump light path and the signal light path of the master oscillator power amplifier module 10.

[0048] In Figure 4 In the embodiment shown, the seed light chip 720 is also disposed on the housing 100 for providing seed light pulses. The seed light collimator 740 is coupled with the gain fiber 20 for coupling the seed light pulses to the gain fiber 20. After the seed light pulses enter the gain fiber 20, the gain fiber 20 combines the energy provided by the pump chip 200 with the seed light pulses to realize amplification of the optical signal.

[0049] According to a third aspect of the embodiments of the present disclosure, another fiber laser system is provided. With reference to the above Figure 3 , the fiber laser system according to the embodiments of the present disclosure comprises: the master oscillator power amplifier module 10 according to any of the above embodiments of the first aspect; a seed light module arranged outside the housing of the master oscillator power amplifier module 10, for providing seed light pulses; and a seed light collimator.

[0050] In some embodiments, as shown in Figure 3 , the seed light collimator arranged outside the housing of the master oscillator power amplifier module 10 can be coupled with the gain fiber 20, for coupling the seed light pulses to the gain fiber 20 to achieve optical amplification.

[0051] According to a fourth aspect of the embodiments of the present disclosure, a laser radar is provided. The laser radar comprises the fiber laser system according to any of the above embodiments of the second aspect; or the fiber laser system according to any of the above embodiments of the third aspect.

[0052] The technical effects that can be achieved by the fiber laser system and the laser radar according to the embodiments of the present disclosure can refer to the related descriptions in the above Figure 2 to Figure 3 described embodiments, which will not be repeated here.

[0053] The following describes some exemplary schemes of the present disclosure.

[0054] Scheme 1, a master oscillator power amplifier module for a laser radar, comprising:

[0055] a housing;

[0056] a pump chip arranged in the housing, for providing first light energy having a first wavelength, wherein the first light energy will propagate along an optical path;

[0057] a first optical element group arranged in the housing, for pre-processing the first light energy;

[0058] a gain fiber collimator coupled with a gain fiber, for coupling the pre-processed first light energy to the gain fiber; and

[0059] a dichroic mirror arranged on the optical path between the first optical element group and the gain fiber collimator, for directing the pre-processed first light energy to the gain fiber collimator.

[0060] Scheme 2, the master oscillator power amplifier module according to Scheme 1, wherein the first optical element group comprises at least one of: a slow-axis collimator and a fast-axis collimator.

[0061] Scheme 3, the master oscillator power amplifier module according to any preceding scheme, wherein the first optical element group further comprises at least one first mirror disposed at an end of the first optical element group on the optical path proximate to the dichroic mirror for directing the pre-processed first optical energy to the dichroic mirror.

[0062] Scheme 4, the master oscillator power amplifier module according to any preceding scheme, wherein the gain fiber collimator is disposed on a first side wall of the housing, the first side wall having a first optical window formed therein through which the dichroic mirror directs the pre-processed first optical energy to the gain fiber collimator.

[0063] Scheme 5, the master oscillator power amplifier module according to any preceding scheme, wherein the master oscillator power amplifier module further comprises:

[0064] a second optical element group disposed in the housing, the second optical element group receiving second optical pulses emitted from the gain fiber and directed via the dichroic mirror, the second optical pulses having a second wavelength different from the first wavelength.

[0065] Scheme 6, the master oscillator power amplifier module according to scheme 5, wherein the second optical element group comprises:

[0066] a beam splitter for splitting the second optical pulses into third and fourth sub-optical pulses, and

[0067] an isolator disposed between the beam splitter and the dichroic mirror.

[0068] Scheme 7, the master oscillator power amplifier module according to scheme 5 or 6, wherein the second optical element group further comprises:

[0069] at least one second mirror for directing the fourth sub-optical pulses;

[0070] a third sub-optical pulse collimator for pre-processing the third sub-optical pulses from the beam splitter; and

[0071] a fourth sub-optical pulse collimator for pre-processing the fourth sub-optical pulses from the beam splitter and directed via the at least one second mirror.

[0072] Scheme 8, the master oscillator power amplifier module according to Scheme 7, wherein the third sub-optical pulse collimator and the fourth sub-optical pulse collimator are disposed on a second side wall of the housing different from the first side wall, the second side wall having a third optical window and a fourth optical window formed therein, wherein the third sub-optical pulse is directed to the third sub-optical pulse collimator via the third optical window by the beam splitter, and the fourth sub-optical pulse is directed to the fourth sub-optical pulse collimator via the fourth optical window by the at least one second mirror.

[0073] Scheme 9, the master oscillator power amplifier module according to any one of Schemes 5-8, wherein at least one of the gain fiber collimator, the third sub-optical pulse collimator, and the fourth sub-optical pulse collimator is an integrated collimator; or,

[0074] at least one of the gain fiber collimator, the third sub-optical pulse collimator, and the fourth sub-optical pulse collimator is a combination of a separate fiber ferrule and a lens.

[0075] Scheme 10, the master oscillator power amplifier module according to any one of Schemes 5-8, wherein the first optical element group, the second optical element group, the gain fiber collimator, and the dichroic mirror are bonded to the housing.

[0076] Scheme 11, the master oscillator power amplifier module according to any one of Schemes 1-10, wherein the pump chip is soldered to the housing or bonded to the housing.

[0077] Scheme 12, the master oscillator power amplifier module according to any one of Schemes 1-11, wherein the housing further comprises a cover portion to provide a hermetic seal.

[0078] Scheme 13, the master oscillator power amplifier module according to any one of Schemes 1-12, wherein the housing is made of metal.

[0079] Scheme 14, a fiber laser system, comprising:

[0080] the master oscillator power amplifier module according to any one of Schemes 1-13;

[0081] a seed light chip disposed in a housing of the master oscillator power amplifier module for providing seed light pulses;

[0082] a seed light collimator coupled to the gain fiber for coupling the seed light pulses to the gain fiber.

[0083] Scheme 15, a fiber laser system, comprising:

[0084] the master oscillator power amplifier module according to any one of Schemes 1-13;

[0085] A seed light module, disposed outside the housing of the main oscillation amplifier module, is used to provide seed light pulses; and

[0086] A seed light collimator, which is coupled to the gain fiber, is used to couple the seed light pulse to the gain fiber.

[0087] Option 16: A lidar, comprising:

[0088] The fiber laser system according to Scheme 14 or Scheme 15.

[0089] The above description is merely a preferred embodiment of this disclosure and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in the embodiments of this disclosure is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described inventive concept. For example, technical solutions formed by substituting the above-described features with (but not limited to) technical features with similar functions disclosed in the embodiments of this disclosure.

Claims

1. A master oscillator power amplifier module for a lidar, comprising: Comprising: a housing; a pump chip disposed in the housing for providing first light energy having a first wavelength, wherein the first light energy is to propagate along an optical path; a first optical element group disposed in the housing for pre-processing the first light energy; a gain fiber collimator coupled with a gain fiber for coupling the pre-processed first light energy to the gain fiber; and a dichroic mirror disposed on the optical path between the first optical element group and the gain fiber collimator for directing the pre-processed first light energy to the gain fiber collimator. The first optical element group comprises at least one of: a slow axis collimator and a fast axis collimator.

2. The master oscillator power amplifier module of claim 1, wherein, The first optical element group further comprises at least one first mirror disposed at an end of the first optical element group on the optical path close to the dichroic mirror for directing the pre-processed first light energy to the dichroic mirror.

3. The master oscillator power amplifier module of claim 1, wherein, The gain fiber collimator is disposed on a first side wall of the housing, the first side wall having a first light window formed thereon via which the dichroic mirror directs the pre-processed first light energy to the gain fiber collimator.

4. The master oscillator power amplifier module of claim 1, wherein, The master oscillator power amplifier module further comprises:

5. The master oscillator power amplifier module of any one of claims 1-4, wherein, a second optical element group disposed in the housing, the second optical element group receiving a second light pulse having a second wavelength different from the first wavelength, the second light pulse being emitted from the gain fiber and directed via the dichroic mirror. The second optical element group comprises:

6. The master oscillator power amplifier module of claim 5, wherein, a beam splitter for splitting the second light pulse into a third sub-light pulse and a fourth sub-light pulse, and an isolator disposed between the beam splitter and the dichroic mirror. The second optical element group further comprises:

7. The master oscillator power amplifier module of claim 6, wherein, at least one second mirror for directing the fourth sub-light pulse; a third sub-light pulse collimator for pre-processing the third sub-light pulse from the beam splitter; and a fourth sub-light pulse collimator for pre-processing the fourth sub-light pulse from the beam splitter and directed via the at least one second mirror. The third sub-light pulse collimator and the fourth sub-light pulse collimator are disposed on a second side wall of the housing different from the first side wall, the second side wall having a third light window and a fourth light window formed thereon, wherein the beam splitter directs the third sub-light pulse to the third sub-light pulse collimator via the third light window, and the at least one second mirror directs the fourth sub-light pulse to the fourth sub-light pulse collimator via the fourth light window.

8. The master oscillator power amplifier module of claim 7, wherein, At least one of the gain fiber collimator, the third sub-light pulse collimator and the fourth sub-light pulse collimator is an integrated collimator; or 9. The master oscillator power amplifier module of claim 7, wherein, At least one of the gain fiber collimator, the third sub-light pulse collimator and the fourth sub-light pulse collimator is a combination of a separate fiber ferrule and a lens. The first optical element group, the second optical element group, the gain fiber collimator and the dichroic mirror are bonded to the housing.

10. The master oscillator power amplifier module of claim 5, wherein, The pump chip is soldered to the housing or bonded to the housing.

11. The master oscillator power amplifier module of claim 1, wherein, ​ 12. The master oscillator power amplifier module of claim 1, wherein, The housing further comprises a lid portion to provide a hermetic seal.

13. The master oscillator power amplifier module of claim 1, wherein, The housing is made of metal.

14. A fiber laser system, characterized by, Comprising: The master oscillator power amplifier module according to any one of claims 1-13; a seed light chip disposed in the housing of the master oscillator power amplifier module for providing seed light pulses; a seed light collimator coupled with the gain optical fiber for coupling the seed light pulses to the gain optical fiber.

15. A fiber laser system, comprising: Comprising: The master oscillator power amplifier module according to any one of claims 1-13; a seed light module disposed outside the housing of the master oscillator power amplifier module for providing seed light pulses; and a seed light collimator coupled with the gain optical fiber for coupling the seed light pulses to the gain optical fiber.

16. A lidar, comprising: Comprising: The fiber laser system according to claim 14 or claim 15.

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