High-power high-brightness semiconductor laser

Abstract

The utility model discloses a high-power high-brightness semiconductor laser, which belongs to the technical field of semiconductor laser design, and comprises N low-power laser pumping source generators, N low-power laser pumping source generators, N high-power laser pumping source generators, N high-power laser pumping source generators and N high-power laser pumping source generators, and the N low-power laser pumping source generators are used for providing N low-power laser beams for a whole laser system; the N small-power laser pumping source generators are used for generating small-power laser, the N energy transmission optical fibers respectively correspond to the N small-power laser pumping source generators and are used for transmitting laser, and the N energy transmission optical fibers are fixed in a channel formed by quartz glass tubes. As the connection process of the incident end face and the emergent end face of the energy transmission optical fiber, the gain optical fiber and the like is simplified, the system damage caused by the end face structure is effectively reduced; in addition, the adopted focusing lens is simple in design and processing, so that the production and manufacturing cost of the laser is reduced to a great extent.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductor laser design, and more specifically, to a high-power and high-brightness semiconductor laser. Background Art

[0002] With the progress of semiconductor lasers in terms of output power, conversion efficiency, service life, etc., high-power semiconductor laser systems have begun to be widely used in industrial, military, nuclear energy and other fields.

[0003] However, the average power of the laser that can be transmitted by domestic energy transmission fibers is in the order of hundreds of watts, which cannot meet the laser transmission requirements of the fiber-coupled semiconductor laser pumping source module with a high-brightness and high-stability average power of the order of kilowatts. The optical power emitted by a single semiconductor laser pumping source module is small. When multiple pumping light sources are combined into a beam of light, the beam quality will decline, and the processing requirements for energy fibers are high, which is prone to problems such as burning, reducing the service life of the semiconductor laser. The spots of the light output by the semiconductor laser in the fast axis direction and the slow axis direction are inconsistent, and the beam qualities in the two directions differ greatly, there is astigmatism, which limits its application in many fields. When using optical fibers to transmit high-power lasers, the misalignment of fiber joints, end face reflection and optical damage are the main problems for laser coupling into optical fibers. In application fields such as industrial processing and military, higher beam quality is required, which puts forward requirements for improving the beam quality of semiconductor lasers. And the beam shaping of semiconductor lasers can improve the beam quality and increase the brightness. Therefore, studying the beam propagation characteristics of semiconductor lasers and performing beam shaping lay a solid foundation for broadening the application of semiconductor lasers.

[0004] Therefore, a high-power and high-brightness semiconductor laser is proposed to solve the above problems. Summary of the Utility Model

[0005] In order to overcome the deficiencies of the prior art, the purpose of the utility model is to provide a high-power and high-brightness semiconductor laser. Through a laser multi-channel beam combiner, a gain fiber, a fast and slow axis collimator and a focusing lens, since the connection process of the incident and exit end faces of the energy transmission fiber, the gain fiber, etc. is simplified, the system damage caused by the end face structure is effectively reduced; in addition, the design and processing of the adopted focusing lens are simple, which greatly reduces the production and manufacturing cost of the laser of the utility model.

[0006] The above technical purpose of the utility model is achieved through the following technical solutions:

[0007] A high-power and high-brightness semiconductor laser, comprising:

[0008] N small-power laser pumping source generators: providing N small-power laser beams for the entire laser system;

[0009] N energy transfer optical fibers: corresponding to N low-power laser pump source generators respectively, for transmitting laser light;

[0010] One multi-channel laser beam combiner: fixing N energy transfer optical fibers in a channel composed of a quartz glass tube;

[0011] One gain optical fiber: the high-power combined laser light emitted from the multi-channel laser beam combiner passes through this gain optical fiber;

[0012] One EFL = 0.9mm fast-axis collimating mirror: for compressing the divergence angle of the high-power laser beam in the fast-axis direction after gain;

[0013] One microlens array with EFL = 2.2mm: collimating the beam in the slow-axis direction after fast-axis collimation, reducing the divergence angle in the slow-axis direction;

[0014] Beam expansion and collimation system: using an inverted telescope system to further reduce the divergence angle in the slow-axis direction and increase the spot size in the slow-axis direction of the laser beam collimated in the fast and slow axes;

[0015] Focusing lens group: further focusing and imaging the expanded laser beam through a radially tapered cylindrical optical lens to form an available laser beam;

[0016] Damage feedback mechanism of the energy transfer optical fiber: composed of two copper metal layers distributed parallel to the optical fiber and an external circuit.

[0017] Refer to Figure 1 As shown, for the N energy transfer optical fibers: the laser propagates in the core of the energy transfer optical fiber, and the refractive index of the cladding outside the core is less than that of the core to prevent the laser from passing through the cladding and transmitting to the outside.

[0018] Refer to Figure 1 As shown, for the one multi-channel laser beam combiner: N energy transfer optical fibers are evenly distributed within a circle centered on the indicating optical fiber, and the middle gap is bonded with a special thermal conductive glue, and air bubbles or impurity substances are avoided in the glue, and the end face of the multi-channel laser beam combiner is made flat and smooth by grinding.

[0019] Refer to Figure 1 As shown, for the one gain optical fiber: two optical gratings with relatively high reflectivity are used as mirrors and placed at both ends of the ytterbium-doped optical fiber to form a linear resonant cavity to enhance mode selection.

[0020] For the damage feedback mechanism of the energy transfer optical fiber: when the optical fiber is damaged and the high-power laser leaks out and burns the metal layer, the external circuit cuts off the incident light to protect the energy transfer optical cable.

[0021] Refer to Figure 1As shown, the beam expanding and collimating system: When the laser beam passes through the fast-axis collimating mirror and the microlens array, it enters the beam expanding and collimating system. The inverted telescope system changes the propagation path of the beam, increasing the spot size of the laser beam in the slow-axis direction.

[0022] In summary, the present utility model has the following beneficial effects:

[0023] In this solution, through the laser multi-channel beam combiner, gain fiber, fast and slow axis collimators, and focusing lens, since the connection process of the incident and exit end faces of the energy transmission fiber, gain fiber, etc. is simplified, the system damage caused by the end face structure is effectively reduced; in addition, the design and processing of the adopted focusing lens are simple, greatly reducing the production and manufacturing cost of the laser of the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the schematic diagram of the overall structure in this embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following further describes the present utility model in detail with reference to the drawings.

[0026] Among them, the same components are denoted by the same reference numerals. It should be noted that the terms "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the directions in the drawings, and the terms "bottom surface" and "top surface", "inner" and "outer" refer to the directions towards or away from the geometric center of the specific component respectively.

[0027] Referring to Figure 1 shown, a high-power and high-brightness semiconductor laser in a preferred embodiment of the present utility model includes:

[0028] N small-power laser pump source generators: providing N small-power laser beams for the entire laser system;

[0029] N energy transmission fibers: corresponding to N small-power laser pump source generators respectively, for transmitting laser;

[0030] A multi-channel laser beam combiner: fixing the N energy transmission fibers in the channels formed by quartz glass tubes;

[0031] A gain fiber: the combined high-power laser emitted from the multi-channel laser beam combiner passes through this gain fiber;

[0032] An EFL = 0.9mm fast-axis collimating mirror: used to compress the divergence angle of the high-power laser beam in the fast-axis direction after gain;

[0033] A microlens array with EFL = 2.2mm: collimating the beam after fast-axis collimation in the slow-axis direction, reducing the divergence angle in the slow-axis direction;

[0034] Beam expansion and collimation system: After collimating the laser beam in the fast and slow axes using an inverted telescope system, the divergence angle of the slow axis of the laser beam is further reduced and the spot size of the slow axis is increased.

[0035] Focusing lens group: The expanded laser beam is further focused and imaged through a cylindrical optical lens with a radially varying gradient to form an available laser beam.

[0036] Damage feedback mechanism of the energy transmission fiber: It consists of two layers of copper metal layers distributed parallel to the fiber and an external circuit.

[0037] Refer to Figure 1 As shown, the N energy transmission fibers: Laser propagates in the core of the energy transmission fiber, and the refractive index of the cladding outside the core is less than that of the core to prevent the laser from transmitting through the cladding to the outside.

[0038] Refer to Figure 1 As shown, the multi-channel laser beam combiner: The N energy transmission fibers are evenly distributed within a circle centered on the indicating fiber, and the middle gap is bonded with a special thermal conductive glue, and bubbles or impurity substances are avoided in the glue. The end face of the multi-channel laser beam combiner is made flat and smooth by grinding.

[0039] Refer to Figure 1 As shown, the gain fiber: Two high-reflectivity fiber gratings are used as mirrors and placed at both ends of the ytterbium-doped fiber to form a linear resonant cavity to enhance mode selection.

[0040] The damage feedback mechanism of the energy transmission fiber: When the fiber is damaged and high-power laser leaks out and burns the metal layer, the external circuit cuts off the incident light to protect the energy transmission optical cable.

[0041] Refer to Figure 1 As shown, the beam expansion and collimation system: When the laser beam passes through the fast-axis collimating mirror and the microlens array, it enters the beam expansion and collimation system. The inverted telescope system changes the propagation path of the beam, increasing the spot size of the laser beam in the slow-axis direction.

[0042] High-power high-brightness semiconductor lasers work in cooperation with multiple components to combine, amplify, collimate, shape, and focus the light emitted by multiple low-power laser pump source generators, and finally output high-power laser beams with high beam quality. The low-power laser pump source generators, N low-power laser pump source generators are independent semiconductor laser pump sources, providing N low-power laser beams for the entire system. These low-power beams serve as the basic input for subsequent processing. The energy transmission fiber corresponds one-to-one with the low-power laser pump source generators. The energy transmission fiber serves as the propagation medium for the laser, and the laser propagates in the core. Since the refractive index of the cladding outside the core is less than that of the core, the laser is confined to the core and cannot pass through the cladding to the outside. Multi-channel laser beam combination: Fix the N energy transmission fibers in the channels formed by a quartz glass tube. The energy transmission fibers are evenly distributed within a circle centered on the indicating fiber. The middle gap is bonded with a special thermal conductive glue to avoid the presence of air bubbles or impurity substances in the glue to prevent thermal damage. By adjusting parameters such as the position of the energy transmission fiber in the beam combiner, the core shape, and the laser frequency band, superimposed laser beams with different requirements can be formed. At the exit end face of the beam combiner, N low-power laser beams are superimposed on the imaging surface of the high-reflection grating to form a high-power laser beam, and the spot can be adjusted according to the position relationship of the energy transmission fiber in the core. The gain fiber: The high-power laser beam after beam combination emitted from the multi-channel laser beam combiner enters the gain fiber. Two fiber gratings with relatively high reflectivity are set at both ends of the gain fiber as reflectors to form a linear resonant cavity to enhance mode selection. The fiber grating can be fused to the ytterbium-doped fiber, and at the same time, the size of the laser spot can be controlled. After the single high-power laser beam formed on the imaging surface of the high-reflection grating passes through the linear resonant cavity in the gain fiber to improve the laser beam quality, it is output from the low-reflection grating fused at the exit of the gain fiber as a high-power laser beam with a high beam density. Fast-axis collimating mirror (EFL = 0.9mm): Compress the divergence angle of the high-power laser beam in the fast-axis direction after amplification to reduce the divergence angle in the fast-axis direction. Micro-lens array (EFL = 2.2mm): Collimate the beam in the slow-axis direction after fast-axis collimation. Use the micro-lens array to collimate the beam in the slow-axis direction to reduce the divergence angle in the slow-axis direction. Use an inverted telescope system to further reduce the divergence angle in the slow-axis direction of the laser beam collimated in the fast and slow axes, increase the spot size in the slow axis, and perform beam expansion and collimation. The expanded laser beam passes through a radially graded cylindrical optical lens to further focus and image the laser beam, forming a usable laser beam with a relatively high energy density and beam brightness. Adjust the size of the beam spot to output a high-power and high-brightness laser beam for practical applications. The damage feedback system consists of two layers of copper metal layers distributed parallel to the fiber and an external circuit. When the energy transmission fiber is damaged and high-power laser leaks out, it will burn the metal layer, and at this time, the external circuit will cut off the incident light to protect the energy transmission optical cable.

[0043] The low-power laser beams emitted by multiple low-power laser pump source generators are transmitted through an energy transmission optical fiber to a multi-channel laser beam combiner for beam combination, forming a high-power laser beam. Then, it successively passes through a gain optical fiber to improve the beam quality, a fast-axis collimating mirror and a microlens array to collimate the fast axis and the slow axis directions respectively, and an expanding and collimating system to further optimize the beam characteristics in the slow axis direction. Finally, it is focused and imaged through a focusing lens group to output a high-power laser beam with high beam quality. At the same time, by adjusting the parameters of each component and optimizing the design, different application requirements can be met. The damage feedback mechanism protects the energy transmission optical fiber in real time during the operation of the system, improving the reliability and stability of the system.

[0044] The above shows and describes the basic principles, main features and advantages of the present utility model. Those skilled in the art should understand that the present utility model is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present utility model. Without departing from the spirit and scope of the present utility model, the present utility model will have various changes and improvements, and these changes and improvements all fall within the scope of the present utility model claimed. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents.

Claims

1. A high-power and high-brightness semiconductor laser, characterized in that: Including: N low-power laser pump source generators: providing N low-power laser beams for the entire laser system; N energy transmission optical fibers: corresponding to the N low-power laser pump source generators respectively, and used for transmitting laser; One multi-channel laser beam combiner: fixing the N energy transmission optical fibers in the channels formed by quartz glass tubes; One gain optical fiber: the high-power laser beam after beam combination emitted from the multi-channel laser beam combiner passes through this gain optical fiber; One fast-axis collimating mirror with EFL = 0.9 mm: used to compress the divergence angle of the high-power laser beam in the fast-axis direction after gain; One microlens array with EFL = 2.2 mm: collimating the beam after fast-axis collimation in the slow-axis direction to reduce the divergence angle in the slow-axis direction; Beam expansion and collimation system: using an inverted telescope system to further reduce the divergence angle in the slow-axis direction and increase the spot size in the slow-axis direction of the laser beam after collimation in the fast and slow axes; Focusing lens group: further focusing and imaging the expanded laser beam through a cylindrical optical lens with a radially varying gradient to form an available laser beam; Damage feedback mechanism of the energy transmission optical fiber: composed of two copper metal layers distributed parallel to the optical fiber and an external circuit.

2. The high-power and high-brightness semiconductor laser according to claim 1, wherein: The N energy transmission optical fibers: laser propagates in the core of the energy transmission optical fiber, and the refractive index of the cladding outside the core is less than that of the core to prevent the laser from passing through the cladding and transmitting to the outside.

3. A high-power and high-brightness semiconductor laser according to claim 1, characterized in that: The one multi-channel laser beam combiner: the N energy transmission optical fibers are evenly distributed within the circumference centered on the indicating optical fiber, and the middle gap is bonded with a special thermal conductive glue, and air bubbles or impurity substances are avoided in the glue. The end face of the multi-channel laser beam combiner is made flat and smooth by grinding.

4. A high-power and high-brightness semiconductor laser according to claim 1, characterized in that: The one gain optical fiber: using two optical gratings with relatively high reflectivity as mirrors and placing them at both ends of the ytterbium-doped optical fiber to form a linear resonant cavity to enhance mode selection.

5. A high-power and high-brightness semiconductor laser according to claim 1, characterized in that: The damage feedback mechanism of the energy transmission optical fiber: when the optical fiber is damaged and the high-power laser leaks out and burns the metal layer, the external circuit cuts off the incident light to protect the energy transmission optical cable.

6. A high-power and high-brightness semiconductor laser according to claim 1, wherein: The beam expansion and collimation system: when the laser beam is processed by the fast-axis collimating mirror and the microlens array and then enters the beam expansion and collimation system, the inverted telescope system changes the propagation path of the beam, so that the spot size of the laser beam in the slow-axis direction increases.

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