Laser beam combining system and laser beam combining method

Abstract

The invention provides a laser beam combining system and a laser beam combining method, and relates to the technical field of optics. The system comprises a plurality of light emitting modules, a beam combining module, a monitoring module and a one-way light splitting module which is respectively connected with the light emitting modules, the beam combining module and the monitoring module. Through cooperative work of the one-way light splitting module and the beam combining module, a plurality of emitted lasers can be combined, and the overall light beam output power is improved. After beam combination is completed, the combined light beam can return to the one-way light splitting module based on the mutual anisotropy of light path transmission, the one-way light splitting module separates the combined light beam from the emitted laser, the monitoring module monitors the optical power of the combined light beam, and the beam combination precision of the combined light beam is monitored based on the optical power of the combined light beam. Compared with a method for monitoring the position by using space photoelectric equipment, the scheme for monitoring the beam combining precision based on the optical power not only can effectively reduce the equipment cost, but also can realize the calibration monitoring of the optical path, and ensures the beam combining precision of the combined light beam.

Description

Technical Field

[0001] The present application relates to the field of optical technology, and in particular to a laser beam combining system and a laser beam combining method. Background Art

[0002] With the continuous development of space laser technology, different specific requirements for space laser energy and the number of wavelengths have gradually emerged in the fields of military, medical, and communications. For example, space laser communication systems require coaxial emission of lasers in the 1064nm and 1550nm bands as beacon light and communication light. Or the requirements of laser radar for transmission power require strict control of the coaxiality of the system's output light beam. At present, commercial lasers are affected by thermal damage, nonlinear effects, thermal lens effects, component structure, and heat dissipation conditions. The wavelength and power of the output laser are limited, and the multi-band output of optical fiber limits the introduction of spatial light field control technology. Therefore, spatial meter photosynthesis technology is an effective way to break through the output power of a single system laser and ensure the quality of the beam, introduce more space laser modes, expand system functions, and achieve wide spectral range beam combining.

[0003] The existing laser beam combining systems do not have any beam adjustment or monitoring modules. This type of laser beam combining system is unable to cope with the beam separation caused by the laser's own jitter, assembly errors, vibration, ambient temperature changes, etc., which greatly reduces the system's beam quality and efficiency and has low practicality. Summary of the invention

[0004] In order to at least overcome the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a laser beam combining system and a laser beam combining method.

[0005] In a first aspect, an embodiment of the present application provides a laser beam combining system, the laser beam combining system comprising a plurality of light emitting modules, a beam combining module, a monitoring module, and a unidirectional light splitting module respectively connected to the light emitting module, the beam combining module and the monitoring module;

[0006] The unidirectional light splitting module is used to receive the emitted laser from the light emitting module and transmit the emitted laser to the beam combining module, which combines the emitted laser.

[0007] The unidirectional light splitting module is also used to receive at least part of the combined light beam returned by the beam combining module, and separate the combined light beam from the emitted laser;

[0008] The monitoring module is used to receive the separated combined light beam and monitor the beam combining accuracy of the laser beam combining system based on the optical power of the combined light beam.

[0009] In a possible implementation, the unidirectional optical splitting module includes an optical fiber isolator and an optical coupler;

[0010] The first end of the optical fiber isolator is connected to the light emitting module, the second end of the optical fiber isolator is connected to the first end of the optical coupler, and the second end of the optical coupler is connected to the beam combining module.

[0011] In a possible implementation, the unidirectional light splitting module includes an optical circulator;

[0012] The optical circulator comprises a first port, a second port and a third port. The first port is connected to the light emitting module, the second port is connected to the beam combining module, and the third port is connected to the monitoring module.

[0013] In a possible implementation, the beam combining module includes a collimating unit and a beam combining unit;

[0014] The first end of the collimating unit is connected to the unidirectional light splitting module through an optical fiber, and the second end of the collimating unit faces the beam combining unit. The collimating unit is used to convert the light beam in the optical fiber into a collimated light beam in space, and the collimated light beam emerges from the collimating unit at a fixed beam divergence angle;

[0015] The beam combining unit is used to combine a plurality of collimated light beams to form a combined light beam.

[0016] In a possible implementation, the calculation formula for the beam divergence angle is:

[0017]

[0018] Where θ is the divergence angle of the collimated beam, MFD is the mode field diameter, f is the focal length of the collimator unit, and the beam divergence angle is in micro-radians.

[0019] In a possible implementation, the collimation unit includes a fiber collimator, and the beam combining unit includes a beam combining cube.

[0020] In a possible implementation, the monitoring module includes a reflection unit and a monitoring unit, wherein the monitoring unit is connected to the unidirectional light splitting module;

[0021] The reflecting surface of the reflecting unit faces the beam combining unit, and the reflecting unit is used to reflect at least part of the combined light beam to the collimating unit, and then transmit it to the monitoring unit through the unidirectional splitting module. The monitoring unit monitors the beam combining accuracy of the laser beam combining system based on the combined light beam.

[0022] In a possible implementation, the monitoring module further includes a filter unit, and the filter unit is located between the reflection unit and the beam combining unit.

[0023] The filter unit includes a collimating filter structure composed of a pinhole aperture, the reflection unit includes a reflector, and the monitoring unit includes an optical power meter.

[0024] In a second aspect, an embodiment of the present application further provides a laser beam combining method, which is applied to the laser beam combining system of the first aspect, and the method includes:

[0025] The light emitting module generates and emits laser light;

[0026] The unidirectional light splitting unit transmits the emitted laser to the beam combining module, and the beam combining module combines the emitted laser to obtain a combined light beam;

[0027] The unidirectional light splitting module separates at least part of the returned combined light beam from the emitted laser, and the monitoring module receives the separated combined light beam and detects the optical power of the combined light beam;

[0028] Determining whether a beam combining accuracy of the combined light beam meets a preset accuracy based on the optical power of the combined light beam;

[0029] When the beam combining accuracy of the combined light beam does not meet the preset accuracy, the laser beam combining system is adjusted until the beam combining accuracy of the combined light beam meets the preset accuracy.

[0030] In a possible implementation, the beam combining module includes a collimating unit and a beam combining unit, and the beam combining module combines the emitted lasers to obtain a combined light beam, including:

[0031] The collimating unit converts the light beam in the optical fiber into a collimated light beam in space, and the beam combining unit combines a plurality of collimated light beams to form a combined light beam, wherein the collimated light beam is emitted from the collimating unit according to a fixed beam divergence angle;

[0032] The step of judging whether the beam combining accuracy of the combined beam meets the preset accuracy based on the optical power of the combined beam includes:

[0033] The optical coaxiality of the combined light beam is obtained based on the optical power of the combined light beam, and the beam divergence angle is calculated;

[0034] Based on the mathematical relationship between the optical coaxiality and the beam divergence angle, it is determined whether the beam combining accuracy of the combined beam meets the preset accuracy.

[0035] Based on any one of the above aspects, the laser beam combining system and the laser beam combining method provided in the embodiments of the present application include a plurality of light-emitting modules, a beam combining module, a monitoring module, and a unidirectional splitter module respectively connected to the light-emitting module, the beam combining module and the monitoring module. Through the coordinated work of the unidirectional splitter module and the beam combining module, a plurality of emitted lasers can be efficiently combined to improve the overall beam output power. In addition, after the beam combining is completed, the combined beam can be returned to the unidirectional splitter module based on the reciprocity of the optical path transmission, and the combined beam can be separated from the emitted laser by the unidirectional splitter module, and the optical power of the combined beam can be monitored by the monitoring module, and the beam combining accuracy of the combined beam can be monitored based on the optical power of the combined beam. Compared with the method of using space optoelectronic equipment for position monitoring, the solution of monitoring the beam combining accuracy based on optical power in the present application can not only effectively reduce the equipment cost, but also realize the calibration monitoring of the optical path itself to ensure the beam combining accuracy of the combined beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 A schematic diagram of a laser beam combining system provided in an embodiment of the present application Figure 1 ;

[0038] Figure 2 A schematic diagram of a laser beam combining system provided in an embodiment of the present application Figure 2 ;

[0039] Figure 3 A schematic diagram of a laser beam combining system provided in an embodiment of the present application Figure 3 ;

[0040] Figure 4 A schematic flow chart of a laser beam combining method provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0042] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0043] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0044] In the description of this application, it should be noted that the terms "upper", "lower", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0045] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0046] It should be noted that, in the absence of conflict, different features in the embodiments of the present application may be combined with each other.

[0047] The inventors found that in some related schemes, if real-time beam combining status monitoring is to be achieved, it is generally necessary to split the combined light beam into separate detection branches, and then use space optoelectronic equipment for position monitoring. This scheme has two technical problems that limit the large-scale use of the beam combining method. The first is that the detection equipment of the scheme is expensive. To achieve wide-spectrum laser beam combining, a camera with a wide spectral bandwidth must be used. At present, the price of near-infrared band cameras is generally around 100,000, and the price index of detectors entering the mid-infrared band has risen, and the cost is relatively high. The second is that the pixels of the current detectors all have a size range. The beam combining accuracy and resolution cannot be further improved due to the limitation of pixel size, and effective imaging resolution generally requires a 3*3 pixel matrix for analysis, but because the area of ​​the pixel size is in the range of hundreds of microns, if the laser is emitted to change the band, the range of the pixel size will continue to change, and it is impossible to effectively guarantee the good beam combining effect of the beam combining scheme in different bands.

[0048] To solve the problems in the prior art, please refer to Figure 1 An embodiment of the present application provides a laser beam combining system 10, which includes a plurality of light-emitting modules 110, a beam combining module 130, a monitoring module 140, and a unidirectional light splitting module 120 respectively connected to the light-emitting module 110, the beam combining module 130 and the monitoring module 140.

[0049] Each light-emitting module 110 can be respectively connected to a unidirectional splitter module 120, which can receive the emitted laser of the light-emitting module 110 and transmit the emitted laser to the beam combining module 130, which combines the emitted laser. The light-emitting module 110 can be equipped with a laser, which can emit lasers of different wavelengths as needed.

[0050] After the emission laser beam is combined, the combined beam can be returned to the unidirectional splitter module 120 based on the reciprocity of the optical path transmission. The unidirectional splitter module 120 can also receive at least part of the combined beam returned by the beam combining module 130 and separate the combined beam from the emission laser.

[0051] The monitoring module 140 can receive the separated combined light beams and monitor the combining accuracy of the combined light beams based on the optical power of the combined light beams. Specifically, the optical coaxiality of the combined light beams can be obtained based on the optical power of the combined light beams. Based on the optical coaxiality, it can be monitored whether the combining accuracy of the combined light beams meets expectations. When the combining accuracy of the combined light beams does not meet the expected deviation range, the laser beam combining system 10 can be adjusted until the combining accuracy meets the expected deviation range.

[0052] In this embodiment, through the coordinated work of the unidirectional splitter module 120 and the beam combining module 130, multiple emission lasers can be efficiently combined to improve the overall beam output power. In addition, after the beam combining is completed, the combined beam can be returned to the unidirectional splitter module 120 based on the reciprocity of the optical path transmission, and the combined beam can be separated from the emission laser by the unidirectional splitter module 120, and the optical power of the combined beam can be monitored by the monitoring module 140. The beam combining accuracy of the combined beam is monitored based on the optical power of the combined beam. Compared with the method of using spatial optoelectronic equipment for position monitoring, the solution of the present application based on optical power monitoring of beam combining accuracy can not only effectively reduce equipment costs, but also realize the calibration monitoring of the optical path itself to ensure the beam combining accuracy of the combined beam.

[0053] For some possible embodiments, please refer to Figure 2 In order to protect the light emitting module 110 from being affected by the combined light beam, the unidirectional light splitting module 120 may include an optical fiber isolator 121 and an optical coupler 122 connected by optical fibers, wherein the first end of the optical fiber isolator 121 is connected to the light emitting module 110, the second end of the optical fiber isolator 121 is connected to the first end of the optical coupler 122, and the second end of the optical coupler 122 is connected to the beam combining module 130. The optical coupler 122 may be a 2*1 coupler, which may combine the emitted laser and the combined light beam into a single optical fiber link, and the optical fiber isolator 121 may prevent the combined light beam from returning to the light emitting module 110, thereby protecting the light emitting module 110 from being affected by the combined light beam.

[0054] In other embodiments, the unidirectional light splitting module 120 may further include an optical circulator. The optical circulator includes a first port, a second port, and a third port, wherein the first port is connected to the light emitting module 110, the second port is connected to the beam combining module 130, and the third port is connected to the monitoring module 140. The emitted laser of the light emitting module 110 may enter the beam combining module 130 via the first port and the second port, and the combined beam may enter the monitoring module 140 via the second port and the third port, thereby preventing the combined beam transmitted in the reverse direction from entering the emission module.

[0055] In some possible embodiments, please refer again to Figure 2The beam combining module 130 includes a collimating unit 131 and a beam combining unit 132. The first end of the collimating unit 131 can be connected to the unidirectional light splitting module 120 through an optical fiber, and the second end thereof faces the beam combining unit 132. In the beam combining process, the collimating unit 131 can receive the emission laser transmitted by the unidirectional light splitting module 120, and convert the emission laser in the optical fiber into a collimated beam in space. The beam combining unit 132 combines multiple collimated beams to form a combined beam, wherein the collimated beam is emitted from the collimating unit 131 at a fixed beam divergence angle. In addition, the collimating unit 131 can also couple the reflected combined beam to the optical fiber so that it is transmitted to the monitoring unit 142.

[0056] Specifically, the beam combining unit 132 may include a cascaded first beam combining subunit and a second beam combining subunit. The laser beam combining system 10 provided in the present application may include four light emitting modules 110, each of which is connected to the collimating unit 131 via a unidirectional light splitting module 120, wherein the first beam combining subunit may combine the collimated light beams output by any two collimating units 131, and the second beam combining subunit may combine the light beams output by the first beam combining subunit to obtain a combined light beam. Exemplarily, the collimating unit 131 includes a fiber collimator, and the first beam combining element and the second beam combining subunit include a beam combining cube, wherein the wavelength band of the beam combining unit 132 may be quickly replaced based on the wavelength band of the emitted laser, and the coaxial beam combining of different broadband light beams may be quickly realized, and the system has high universality.

[0057] Furthermore, the beam divergence angle can be calculated by the following formula.

[0058]

[0059] Wherein, θ is the beam divergence angle, MFD is the mode field diameter, f is the focal length of the collimator, the mode field diameter has the same unit as the focal length of the collimator unit 131, and the beam divergence angle is in micro-radians. For example, when the laser beam is a visible light source with a wavelength of 543nm, if the mode field diameter is 3.6μm, and the focal length of the fiber collimator is 40㎜, then the beam divergence angle generated by the collimated beam emitted from the fiber collimator is 0.0051° (0.089mrad), which means that the diffusion of the collimated beam is very small, and it can be approximately regarded as parallel light propagating in space.

[0060] Further, please refer again to Figure 2The monitoring module 140 includes a reflection unit 141, a monitoring unit 142 and a filter unit 143. The filter unit 143 is located between the reflection unit 141 and the beam combining unit 132. The reflection unit 141 can reflect at least part of the combined light beam to the collimation unit 131, and transmit it to the monitoring unit 142 after passing through the unidirectional light splitting module 120. The monitoring unit 142 monitors the beam combining accuracy of the laser beam combining system 10 based on the combined light beam. The filter unit 143 can collimate and filter the light beam to ensure the beam quality. Among them, the filter unit 143 can be an optical axis collimation filter structure composed of a pinhole aperture, the reflection unit 141 can include a gold-plated reflector or a silver-plated reflector, and the monitoring unit 142 includes an optical power meter.

[0061] Specifically, the optical power of the combined light beam can be first obtained through an optical power meter, and then the optical coaxiality of the combined light beam can be obtained based on the optical power, and the mathematical relationship between the optical coaxiality and the beam divergence angle can be calculated. When the optical coaxiality of the combined light beam is half of the divergence angle of the collimated light beam, it means that the energy of the combined light beam is the same as or close to the energy of the emitted laser, that is, the deviation range of the optical axis of the combined light beam at this time is within half of the mode field diameter, and the combined light beam can be effectively coupled back to the optical fiber. It can also be considered that the pointing accuracy and beam combining accuracy of the combined light beam are high, and the laser beam combining system 10 has achieved the best beam combining effect. When the optical coaxiality of the combined light beam does not meet half of the divergence angle of the collimated light beam, it can be considered that the numerical deviation between the energy of the combined light beam and the energy of the emitted laser is not within the preset deviation range, and the coaxiality of the combined light beam and the optical fiber collimator is not high, that is, the combined light beam is not effectively coupled back to the optical fiber, and the pointing accuracy and beam combining accuracy of the combined light beam are not high. At this time, it may be because the spatial distribution and wavefront quality of the combined beam do not meet expectations. The collimation unit 131, the beam combining unit 132 or the reflection unit 141 can be precisely adjusted until the coaxiality of the combined beam and the fiber collimator meets the expected requirements. Specifically, the position of the gold-plated reflector can be fine-tuned to ensure that the combined beam can be accurately reflected back to the fiber collimator; or the angle and position of the beam combining cube can be fine-tuned to maximize the beam combining efficiency; or the band of the beam combining unit 132 can be replaced to achieve coaxial beam combining of different broadband beams; or the position or angle of the fiber collimator can be fine-tuned to maximize the coupling of the reflected beam.

[0062] In this embodiment, the optical power of the combined light beam is obtained by the monitoring unit 142, the optical coaxiality of the combined light beam is obtained in reverse based on the optical power, and whether the beam combining accuracy meets expectations is judged based on the mathematical relationship between the optical coaxiality and the divergence angle of the collimated light beam, thereby ensuring the beam combining accuracy and effectively reducing the monitoring cost.

[0063] Please refer to Figure 3In some embodiments, the laser beam combining system may further include a beam expansion module 150 connected to the beam combining unit. The beam expansion module 150 may further expand the combined beam to increase the spatial transmission distance of the beam.

[0064] Based on the same inventive concept, this application also provides a laser beam combining method, for details, please refer to Figure 4 , Figure 4 The following is a flow chart of the laser beam combining method. Figure 4 Each step of the laser beam combining method is described in detail.

[0065] Step S110: The light emitting module generates and emits laser light.

[0066] In this step, the light emitting module 110 may include a laser, and the laser may emit lasers of different wavelength bands according to actual needs.

[0067] Step S120: the unidirectional beam splitting module transmits the emitted laser light to the beam combining module, and the beam combining module combines the emitted laser light to obtain a combined light beam.

[0068] In this step, the unidirectional splitter module 120 can first transmit the emitted laser to the collimation unit 131, and then the collimation unit 131 converts the light beam in the optical fiber into a collimated light beam in space, and the beam combining unit 132 is used to combine multiple collimated light beams to form a combined light beam, wherein the collimated light beam is emitted from the collimation unit 131 according to a fixed beam divergence angle.

[0069] Further, the unidirectional light splitting module 120 can be an optical isolator and an optical coupler 122 connected by an optical fiber, or it can be a three-port optical circulator. Exemplarily, when the unidirectional light splitting module 120 is a three-port optical circulator, the emitted laser of the light emitting module 110 can enter the beam combining module 130 via the first port and the second port, and the combined beam can enter the monitoring module 140 via the second port and the third port, thereby preventing the combined beam transmitted in the reverse direction from entering the emission module. Exemplarily, the laser beam combining system 10 provided in the present application may include four light emitting modules 110, each of which is connected to the collimating unit 131 via the unidirectional light splitting module 120, and the collimating unit 131 can convert the emitted laser in the optical fiber into a collimated beam in space. The beam combining unit 132 may include a plurality of cascaded first beam combining subunits and second beam combining subunits, the first beam combining subunit can combine the collimated beams output by any two collimating units 131, and the second beam combining subunit can combine the beams output by the first beam combining subunit to obtain a combined beam. Among them, the collimation unit 131 can be a fiber collimator, and the first beam combining element and the second beam combining sub-unit include a beam combining cube, which can quickly change the band of the beam combining unit 132 based on the band of the emitted laser, and quickly realize the coaxial beam combining of different broadband light beams.

[0070] Step S130: the unidirectional light splitting module separates at least part of the returned combined light beam from the emitted laser, and the monitoring module receives the separated combined light beam and detects the optical power of the combined light beam.

[0071] In this step, the combined light beam may first pass through the filter unit 143 to reach the reflection unit 141, and the reflection unit 141 returns the combined light beam along the original optical path, and the monitoring module 140 detects the returned combined light beam to obtain the optical power of the combined light beam. Exemplarily, the filter unit 143 may be an optical axis collimating filter structure composed of a pinhole diaphragm, the reflection unit 141 may be a gold-plated reflector or a silver-plated reflector, and the monitoring unit 142 may be an optical power meter.

[0072] Step S140: judging whether the beam combining accuracy of the combined light beam meets the preset accuracy based on the optical power of the combined light beam.

[0073] In this step, the optical coaxiality of the combined light beam may be obtained based on the optical power of the combined light beam, and the light beam divergence angle may be calculated, wherein the light beam divergence angle may be calculated by the following formula.

[0074]

[0075] Wherein, θ is the beam divergence angle, MFD is the mode field diameter, f is the focal length of the collimator, the mode field diameter has the same unit as the focal length of the collimator unit 131, and the beam divergence angle is in micro-radians. For example, when the laser beam is a visible light source with a wavelength of 543nm, if the mode field diameter is 3.6μm, and the focal length of the fiber collimator is 40㎜, then the beam divergence angle generated by the collimated beam emitted from the fiber collimator is 0.0051° (0.089mrad), which means that the diffusion of the collimated beam is very small, and it can be approximately regarded as parallel light propagating in space.

[0076] Next, based on the mathematical relationship between the optical coaxiality and the beam divergence angle, it is determined whether the beam combining accuracy of the combined beam meets the preset accuracy. When the optical coaxiality of the combined beam is half of the divergence angle of the collimated beam, it means that the energy of the combined beam is the same as or close to the energy of the emitted laser, that is, the deviation range of the optical axis of the combined beam is within half of the mode field diameter at this time, and the combined beam can be effectively coupled back to the optical fiber. It can also be considered that the pointing accuracy and beam combining accuracy of the combined beam are high, and the laser beam combining system 10 has achieved the best beam combining effect.

[0077] Step S150: When the beam combining accuracy of the combined light beam does not meet the preset accuracy, the accuracy of the beam combining module is adjusted until the beam combining accuracy of the combined light beam meets the preset accuracy.

[0078] When the optical coaxiality of the combined beam does not meet half of the divergence angle of the collimated beam, it can be considered that the numerical deviation between the energy of the combined beam and the energy of the emitted laser is not within the preset deviation range, and the coaxiality of the combined beam and the fiber collimator is not high, that is, the combined beam is not effectively coupled back to the optical fiber, and the pointing accuracy and combining accuracy of the combined beam are not high. At this time, it may be because the spatial distribution and wavefront quality of the combined beam do not meet expectations. The collimation unit 131, the combining unit 132 or the reflection unit 141 can be precisely adjusted until the coaxiality of the combined beam and the fiber collimator meets the expected requirements. Specifically, the position of the gold-plated reflector can be fine-tuned to ensure that the combined beam can be accurately reflected back to the fiber collimator; or the angle and position of the combining cube can be fine-tuned to maximize the combining efficiency; or the band of the combining unit 132 can be replaced to achieve coaxial combining of different broadband beams; or the position or angle of the fiber collimator can be fine-tuned to maximize the coupling of the reflected beam.

[0079] In this embodiment, the optical power of the combined light beam is obtained by the monitoring unit 142, the optical coaxiality of the combined light beam is obtained in reverse based on the optical power, and whether the beam combining accuracy meets expectations is judged based on the mathematical relationship between the optical coaxiality and the divergence angle of the collimated light beam. Compared with the method of using spatial optoelectronic equipment for position monitoring, the solution of monitoring the beam combining accuracy based on optical power in the present application can not only effectively reduce the equipment cost, but also realize the calibration monitoring of the optical path itself, thereby ensuring the beam combining accuracy of the combined light beam.

[0080] In summary, the present application provides a laser beam combining system and a laser beam combining method, wherein the laser beam combining system includes a plurality of light emitting modules, a beam combining module, a monitoring module, and a unidirectional splitter module respectively connected to the light emitting module, the beam combining module and the monitoring module. Through the coordinated work of the unidirectional splitter module and the beam combining module, a plurality of emitted lasers can be efficiently combined to improve the overall beam output power. In addition, after the beam combining is completed, the combined beam can be returned to the unidirectional splitter module based on the reciprocity of the optical path transmission, and the combined beam can be separated from the emitted laser by the unidirectional splitter module, and the optical power of the combined beam can be monitored by the monitoring module, and the beam combining accuracy of the combined beam can be monitored based on the optical power of the combined beam. Compared with the method of using space optoelectronic equipment for position monitoring, the solution of monitoring the beam combining accuracy based on optical power in the present application can not only effectively reduce the equipment cost, but also realize the calibration monitoring of the optical path itself to ensure the beam combining accuracy of the combined beam.

[0081] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A laser beam combining system, characterized in that: It includes multiple light-emitting modules, beam-combining modules, monitoring modules, and unidirectional light-splitting modules respectively connected to the light-emitting modules, beam-combining modules and monitoring modules; The unidirectional light splitting module is used to receive the emitted laser from the light emitting module and transmit the emitted laser to the beam combining module, which combines the emitted laser. The unidirectional light splitting module is also used to receive at least part of the combined light beam returned by the beam combining module, and separate the combined light beam from the emitted laser; The monitoring module is used to receive the separated combined light beam and monitor the beam combining accuracy of the laser beam combining system based on the optical power of the combined light beam.

2. The laser beam combining system according to claim 1, characterized in that: The unidirectional optical splitting module includes an optical fiber isolator and an optical coupler; The first end of the optical fiber isolator is connected to the light emitting module, the second end of the optical fiber isolator is connected to the first end of the optical coupler, and the second end of the optical coupler is connected to the beam combining module.

3. The laser beam combining system according to claim 1, characterized in that: The unidirectional light splitting module includes an optical circulator; The optical circulator comprises a first port, a second port and a third port. The first port is connected to the light emitting module, the second port is connected to the beam combining module, and the third port is connected to the monitoring module.

4. The laser beam combining system according to claim 1, characterized in that: The beam combining module includes a collimation unit and a beam combining unit; The first end of the collimating unit is connected to the unidirectional light splitting module through an optical fiber, and the second end of the collimating unit faces the beam combining unit. The collimating unit is used to convert the light beam in the optical fiber into a collimated light beam in space, and the collimated light beam emerges from the collimating unit at a fixed beam divergence angle; The beam combining unit is used to combine a plurality of collimated light beams to form a combined light beam.

5. The laser beam combining system according to claim 4, characterized in that: The formula for calculating the beam divergence angle is: Where θ is the divergence angle of the collimated beam, MFD is the mode field diameter, f is the focal length of the collimator unit, and the beam divergence angle is in micro-radians.

6. The laser beam combining system according to claim 4, characterized in that: The collimation unit includes a fiber collimator, and the beam combining unit includes a beam combining cube.

7. The laser beam combining system according to claim 4, characterized in that: The monitoring module includes a reflection unit and a monitoring unit, wherein the monitoring unit is connected to the unidirectional light splitting module; The reflecting surface of the reflecting unit faces the beam combining unit, and the reflecting unit is used to reflect at least part of the combined light beam to the collimating unit, and then transmit it to the monitoring unit through the unidirectional splitting module. The monitoring unit monitors the beam combining accuracy of the laser beam combining system based on the combined light beam.

8. The laser beam combining system according to claim 7, characterized in that: The monitoring module also includes a filter unit, which is located between the reflection unit and the beam combining unit. The filter unit includes a collimating filter structure composed of a pinhole aperture, the reflection unit includes a reflector, and the monitoring unit includes an optical power meter.

9. A laser beam combining method, characterized in that: The laser beam combining system according to claim 1 to claim 8, wherein the method comprises: The light emitting module generates and emits laser light; The unidirectional light splitting unit transmits the emitted laser to the beam combining module, and the beam combining module combines the emitted laser to obtain a combined light beam; The unidirectional light splitting module separates at least part of the returned combined light beam from the emitted laser, and the monitoring module receives the separated combined light beam and detects the optical power of the combined light beam; Determining whether a beam combining accuracy of the combined light beam meets a preset accuracy based on the optical power of the combined light beam; When the beam combining accuracy of the combined light beam does not meet the preset accuracy, the laser beam combining system is adjusted until the beam combining accuracy of the combined light beam meets the preset accuracy.

10. The laser beam combining method according to claim 9, characterized in that: The beam combining module includes a collimating unit and a beam combining unit. The beam combining module combines the emitted lasers to obtain a combined beam, including: The collimating unit converts the light beam in the optical fiber into a collimated light beam in space, and the beam combining unit combines a plurality of collimated light beams to form a combined light beam, wherein the collimated light beam is emitted from the collimating unit according to a fixed beam divergence angle; The step of judging whether the beam combining accuracy of the combined beam meets the preset accuracy based on the optical power of the combined beam includes: The optical coaxiality of the combined light beam is obtained based on the optical power of the combined light beam, and the beam divergence angle is calculated; Based on the mathematical relationship between the optical coaxiality and the beam divergence angle, it is determined whether the beam combining accuracy of the combined beam meets the preset accuracy.

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