Interference filter type external cavity semiconductor laser

Abstract

An interference filter type external cavity semiconductor laser is characterized by being composed of a laser base, a laser light source assembly, a filter wavelength adjusting assembly, a cat eye reflection optical assembly and a cavity length temperature control tuning device. The laser provided by the utility model is high in structural force and thermal stability, integrates the functions of laser beam expanding collimation, laser diode LD temperature control and monitoring, external cavity output frequency tuning, laser mode selection, laser frequency stabilization and spatial light adjustment, is not sensitive to imbalance caused by mechanical and thermal disturbances, and is high in reliability. Compared with the prior art, the cat eye laser has the advantages that wavelength sensitivity, external cavity feedback, frequency noise and vibration sensitivity are reduced, and the cat eye laser is stable, simple in structure, low in cost and high in performance, has frequency stability and narrower line width, meets harsh vibration conditions such as transportation and rocket launching, and is suitable for working environments such as space and ground.

Description

Technical Field

[0001] The utility model relates to a semiconductor laser, in particular to an interference filter type external cavity semiconductor laser. Background Art

[0002] The uncertainty and stability of ground optical clocks have reached e-18. Laser linewidth is one of the main factors limiting the performance of optical clocks. In order to develop higher-performance optical clocks, the development of ultra-stable, ultra-narrow linewidth, and interference filter-type external cavity semiconductor lasers that meet the harsh vibration conditions of transportation and rocket launches, suitable for working environments such as space and ground, has broad application prospects.

[0003] Commonly used external cavity grating feedback semiconductor lasers include Littman structure and Littrow structure, see Figure 1 , Figure 2 The two structures require precise alignment during commissioning and are sensitive to optical misalignment caused by environmental pressure, acoustic and mechanical disturbances, thermal deformation, and noisy environments. Utility Model Content

[0004] In order to solve the problems of the above-mentioned external cavity grating feedback semiconductor laser, the utility model provides an interference filter type external cavity semiconductor laser, which is self-aligned, insensitive to the misalignment in the cavity, mechanically stable, and the filter allows linear cavity design, is not very sensitive to the misalignment caused by mechanical and thermal disturbances, reduces the wavelength sensitivity and external cavity feedback, frequency noise, and vibration sensitivity, and the interference filter type external cavity semiconductor laser is stable, simple in structure, low in cost, high in performance, and has frequency stability and narrower line width. The interference filter type external cavity semiconductor laser integrates the functions of cavity length temperature control, laser beam expansion and collimation, laser diode LD temperature control and monitoring, external cavity output frequency tuning, laser mode selection, laser frequency stabilization, and spatial light regulation, realizing a miniaturized, lightweight, highly stable, and highly reliable narrow line width cat's eye laser, meeting the harsh vibration conditions of transportation and rocket launch, and is suitable for working environments such as space and ground.

[0005] The technical solutions of the utility model are as follows:

[0006] An interference filter type external cavity semiconductor laser is characterized in that it is composed of a laser base, a laser light source component, a filter wavelength adjustment component, a cat's eye reflection optical component and a cavity length temperature control tuning device.

[0007] The laser base is a whole consisting of a first collimator mirror mounting hole, a U-shaped groove mounting plane, a second collimator mirror mounting hole, a filter rotation adjustment hole, a light source mounting surface and a laser tube heat conduction surface, and all the light holes are coaxial;

[0008] The laser light source assembly is composed of an LD laser tube, an LD housing, an LD pressure screw, a first collimating lens, a first collimating lens barrel, a first collimating lens mounting seat, a third PEEK thermal insulation pad, a fourth PEEK thermal insulation pad, a multilayer piezoelectric annular actuator PZT and a laser tube Bias Tee circuit. The laser light source assembly is mounted on the light source mounting surface, and the multilayer piezoelectric annular actuator PZT is ensured to be attached to the heat conducting surface of the laser tube.

[0009] The filter wavelength adjustment component is composed of a filter, a filter rotating cylinder and an angle fine-tuner, and the filter wavelength adjustment component is installed in the filter rotating adjustment hole;

[0010] The cat's eye reflective optical assembly is composed of a first collimator, a lens barrel of the first collimator, an output coupling lens, a second collimator and a lens barrel of the second collimator. The first collimator of the cat's eye reflective optical assembly is installed in the first collimator mounting hole; the second collimator lens barrel is installed in the second collimator mounting hole;

[0011] The cavity length temperature control tuning device is composed of a cavity length adjustment piezoelectric ceramic PZT, a heat sink, a TEC, a first PEEK thermal insulation pad, a second PEEK thermal insulation pad, a cavity front cover, a cavity right cover, a cavity left cover, a cavity rear cover and a cavity upper cover. The cavity length adjustment piezoelectric ceramic PZT is glued to the U-shaped groove mounting plane; after the laser light source component, the filter IF wavelength adjustment component, the cat's eye reflection optical component and the laser base are assembled, the laser base is installed on the heat sink through the first PEEK thermal insulation pad and the second PEEK thermal insulation pad, and a TEC is added in the middle. Finally, the cavity front cover, the cavity right cover, the cavity left cover, the cavity rear cover and the cavity upper cover are assembled into a sealed cavity;

[0012] The optical path connection relationship is as follows: the output light of the LD laser tube enters the second collimating lens for collimation, reaches the filter for wavelength adjustment after collimation, then passes through the first collimating lens and the output coupling lens, and finally passes through the second collimating lens to form a cat's eye output laser.

[0013] The laser base, LD housing, LD pressure screw, collimating lens barrel, collimating lens mounting seat, filter IF rotating barrel, collimating lens L1 barrel and collimating lens barrel are all made of indium steel 4J36 material; the material of the heat sink is brass.

[0014] The length of the laser light source assembly from the light-emitting surface of the LD laser tube to the incident end surface of the output coupling mirror, that is, the length of the cat's eye cavity, is controlled at 30 mm.

[0015] Compared with the prior art, experiments show that the technical effects of the utility model are as follows:

[0016] 1. The cavity length of the interference filter type external cavity semiconductor laser is 30mm. It has the advantages of miniaturization, high structural mechanical and thermal stability, integrated cavity length temperature control, laser beam expansion and collimation, temperature control and monitoring of laser diode LD, external cavity output frequency tuning, laser mode selection, laser frequency stabilization and spatial light regulation; the line width of the interference filter type external cavity semiconductor laser is 6KHz.

[0017] 2. The laser base is made of indium steel 4J36 material, and the processing accuracy, coaxiality and angle error can meet the requirements of optical design; the LD housing, LD pressure screw, collimating lens CL barrel, collimating lens CL mounting seat barrel axis cooperate, the filter IF rotating barrel, the first collimating lens barrel, the second collimating lens barrel and the laser base barrel axis are installed in coordination, and the laser directivity accuracy is high;

[0018] 3. The laser light source described above controls the temperature of the laser diode LD lasing through a multilayer piezoelectric ring actuator PZT, and precisely controls the current of the laser diode LD through a laser tube Bias Tee circuit, thereby ultimately achieving frequency tuning of the output laser;

[0019] 5. The filter IF wavelength adjustment component can fine-tune the filter angle through the angle fine-tuner to achieve fine adjustment of the wavelength;

[0020] 6. The temperature control device can achieve fine tuning of the wavelength by adjusting the applied voltage of the piezoelectric ceramic PZT by changing the cavity length; it can avoid the thermal noise and frequency drift of the output laser caused by the thermal expansion of the cavity length due to temperature changes, and the external cavity feedback can also significantly reduce the threshold power of the laser;

[0021] 7. The TEC, the first PEEK thermal insulation pad, the second PEEK thermal insulation pad, the cavity front cover, the cavity right cover, the cavity left cover, the cavity back cover and the cavity top cover provide a stable temperature for the cavity length of the narrow linewidth cat's eye laser of the utility model, reducing the influence of air convection and heat conduction on the interference filter type external cavity semiconductor laser of the utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the Littman structure.

[0023] Figure 2 This is a schematic diagram of the Littrow structure.

[0024] Figure 3 This is a simplified optical path diagram of the interference filter type external cavity semiconductor laser of the utility model.

[0025] Figure 4 This is a schematic diagram of the base structure of the interference filter type external cavity semiconductor laser of the utility model.

[0026] Figure 5 This is a front view of the interference filter type external cavity semiconductor laser of the utility model;

[0027] Figure 6 It is a rear view of the interference filter type external cavity semiconductor laser of the utility model. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings and embodiments, but the protection scope of the present invention shall not be limited thereto.

[0029] Example

[0030] Figure 3 This is a simplified optical path diagram of the interference filter type external cavity semiconductor laser of the utility model. Please refer to Figure 5 As shown in the figure, the interference filter type external cavity semiconductor laser of the utility model is composed of a laser base 1, a laser light source component 2, a filter IF wavelength adjustment component 3, a cat's eye reflection optical component 4 and a cavity length temperature control tuning device 5.

[0031] See also Figure 4 The laser base 1 is a whole including the mounting hole K1 of the first collimator, the U-shaped groove mounting plane M1, the mounting hole K2 of the second collimator, the filter rotation adjustment hole K3, the light source mounting surface M2 and the laser tube heat conduction surface M3, and all the light holes are coaxial;

[0032] See also Figure 6The laser light source assembly 2 comprises: an LD laser tube 2-1, an LD housing 2-2, an LD pressure screw 2-3, a collimating lens CL2-4, a collimating lens CL barrel 2-5, a collimating lens CL mounting seat 2-6, a PEEK thermal insulation pad C2-7, a PEEK thermal insulation pad D2-8, a multilayer piezoelectric annular actuator PZT2-9 and a laser tube Bias Tee circuit 2-10. The LD laser tube 2-1 is pressed into the LD housing 2-2 by the LD pressure screw 2-3. The other side of the LD housing 2-2 is attached to the multilayer piezoelectric annular actuator PZT2-9. The pins of the LD laser tube 2-1 are connected to the laser tube Bias Tee circuit 2-10. Tee circuit 2-10 is welded; the first collimating lens CL2-4 is glued into the first collimating lens CL barrel 2-5 by epoxy resin, and then the first collimating lens CL barrel 2-5 is installed in the mounting seat 2-6 of the first collimating lens CL, and the mounting seat 2-6 of the second collimating lens CL is fixed to the LD housing 2-2 by four screws; the adjusted laser light source assembly 2 is screwed in by four screws, and a third PEEK thermal insulation pad 2-7 is placed under each screw, and then a fourth PEEK thermal insulation pad 2-8 is placed on the other side, and finally the multilayer piezoelectric ring actuator PZT2-9 is attached to the laser tube thermal conductive surface M3 of the laser base 1, and the screws are locked;

[0033] The filter IF wavelength adjustment component 3 includes: the filter IF3-1 is glued in the filter IF rotating cylinder 3-2 by epoxy resin, the angle fine-tuner 3-3 is installed on the left and right sides of the laser base 1 by threads, and the filter IF wavelength adjustment component 3 is fixedly installed in the filter IF rotating adjustment hole K3 by an M2.5 screw;

[0034] The cat's eye reflective optical component 4 comprises: a first collimator L1 (4-1) is glued in a first collimator L1 lens barrel 4-2 by epoxy resin, and then is mounted in the first collimator L1 mounting hole K1 on the laser base 1; the output coupling mirror OC4-3 is glued to one side end face of the cavity length adjustment piezoelectric ceramic PZT5-1 by epoxy resin, and the other end face of the cavity length adjustment piezoelectric ceramic PZT5-1 is glued to the U-shaped groove mounting plane M1 of the laser base 1 by epoxy resin; a second collimator L24-4 is glued in a second collimator L2 lens barrel 4-5 by epoxy resin, and then is mounted in the second collimator L2 mounting hole K2 on the laser base 1;

[0035] The temperature control tuning component 5 includes: adjusting the voltage of the piezoelectric ceramic PZT5-1 by changing the cavity length to achieve fine tuning of the wavelength; the cold surface of the TEC5-3 is attached to the bottom surface of the laser base 1 with indium skin, and the hot surface is attached to the top of the heat sink 5-2 with indium skin; the laser base 1 is padded with a first PEEK insulation pad A (5-4) by six M6 screws, and the second PEEK insulation pad B5-5 is passed under the screws and fixed to the heat sink 5-2; finally, the cavity front cover 5-6, cavity right cover 5-7, cavity left cover 5-8, cavity rear cover 5-9 and cavity upper cover 5-10 are installed to form a sealed cavity.

[0036] The laser base 1, LD housing 2-1, LD pressure screw 2-3, first collimating lens barrel 2-4, first collimating lens mounting base 2-5, filter IF rotating barrel 3-2, first collimating lens barrel 4-2 and second collimating lens barrel 4-6 are all made of indium steel 4J36 material; the material of the heat sink 6-1 is brass.

[0037] The length of the laser light source assembly 2 from the light emitting surface of the LD laser tube 2-1 to the incident end surface of the output coupling mirror 4-3, that is, the cat's eye cavity length is controlled at 30 mm.

[0038] Experiments have shown that the technical effects of the utility model are as follows:

[0039] 1. The cavity length of the interference filter type external cavity semiconductor laser is 30mm. It has the advantages of miniaturization, high structural mechanical and thermal stability, integrated cavity length temperature control, laser beam expansion and collimation, temperature control and monitoring of laser diode LD, external cavity output frequency tuning, laser mode selection, laser frequency stabilization and spatial light regulation; the line width of the interference filter type external cavity semiconductor laser is 6KHz.

[0040] 2. The laser base is made of indium steel 4J36 material, and the processing accuracy, coaxiality and angle error can meet the requirements of optical design; the LD housing, LD pressure screw, collimating lens CL barrel, collimating lens CL mounting seat barrel axis cooperate, the filter IF rotating barrel, the first collimating lens barrel, the second collimating lens barrel and the laser base barrel axis are installed in coordination, and the laser directivity accuracy is high;

[0041] 3. The laser light source described above controls the temperature of the laser diode LD lasing through a multilayer piezoelectric ring actuator PZT, and precisely controls the current of the laser diode LD through a laser tube Bias Tee circuit, thereby ultimately achieving frequency tuning of the output laser;

[0042] 5. The filter IF wavelength adjustment component can fine-tune the filter angle through the angle fine-tuner to achieve fine adjustment of the wavelength;

[0043] 6. The temperature control device can achieve fine tuning of the wavelength by adjusting the applied voltage of the piezoelectric ceramic PZT by changing the cavity length; it can avoid the thermal noise and frequency drift of the output laser caused by the thermal expansion of the cavity length due to temperature changes, and the external cavity feedback can also significantly reduce the threshold power of the laser;

[0044] 7. The TEC, the first PEEK thermal insulation pad, the second PEEK thermal insulation pad, the cavity front cover, the cavity right cover, the cavity left cover, the cavity back cover and the cavity top cover provide a stable temperature for the cavity length of the narrow linewidth cat's eye laser of the utility model, reducing the influence of air convection and heat conduction on the interference filter type external cavity semiconductor laser of the utility model.

[0045] In summary, the interference filter type external cavity semiconductor laser of the utility model has high structural mechanical and thermal stability, and integrates the functions of cavity length temperature control, laser beam expansion and collimation, laser diode temperature control and monitoring, external cavity output frequency tuning, laser mode selection, laser frequency stabilization and spatial light regulation.

Claims

1. An interference filter type external cavity semiconductor laser, characterized in that: The invention is composed of a laser base (1), a laser light source component (2), a filter wavelength adjustment component (3), a cat's eye reflection optical component (4) and a cavity length temperature control tuning device (5). The laser base (1) is a whole consisting of a first collimator mirror mounting hole (K1), a U-shaped groove mounting plane (M1), a second collimator mirror mounting hole (K2), a filter rotation adjustment hole (K3), a light source mounting surface (M2) and a laser tube heat conduction surface (M3), and all the light holes are coaxial; The laser light source assembly (2) is composed of an LD laser tube (2-1), an LD housing (2-2), an LD pressure screw (2-3), a first collimating lens (2-4), a first collimating lens barrel (2-5), a first collimating lens mounting seat (2-6), a third PEEK thermal insulation pad (2-7), a fourth PEEK thermal insulation pad (2-8), a multilayer piezoelectric annular actuator PZT (2-9) and a laser tube Bias Tee circuit (2-10). The laser light source assembly (2) is mounted on the light source mounting surface (M2), while ensuring that the multilayer piezoelectric annular actuator PZT (2-9) is attached to the laser tube thermal conductive surface (M3); The optical filter wavelength adjustment component (3) is composed of an optical filter (3-1), an optical filter rotating cylinder (3-2) and an angle fine-tuner (3-3), and the optical filter wavelength adjustment component (3) is installed in the optical filter rotating adjustment hole (K3); The cat's eye reflective optical component (4) is composed of a first collimator (4-1), a lens barrel (4-2) of the first collimator, an output coupling lens (4-3), a second collimator (4-4) and a second collimator lens barrel (4-5); the first collimator (4-1) of the cat's eye reflective optical component (4) is installed in the first collimator mounting hole (K1); the second collimator lens barrel (4-5) is installed in the second collimator mounting hole (K2); The cavity length temperature control tuning device (5) is composed of a cavity length adjustment piezoelectric ceramic PZT (5-1), a heat sink (5-2), a TEC (5-3), a first PEEK thermal insulation pad (5-4), a second PEEK thermal insulation pad (5-5), a cavity front cover (5-6), a cavity right cover (5-7), a cavity left cover (5-8), a cavity rear cover (5-9) and a cavity upper cover (5-10), wherein the cavity length adjustment piezoelectric ceramic PZT (5-1) is glued to the U-shaped groove mounting plane (M1); the laser light source assembly ( 2) After the filter IF wavelength adjustment component (3), the cat's eye reflective optical component (4) and the laser base (1) are assembled, the laser base (1) is installed on the heat sink (5-2) through the first PEEK thermal insulation pad (5-4) and the second PEEK thermal insulation pad (5-5), and a TEC (5-3) is added in the middle. Finally, the cavity front cover (5-6), cavity right cover (5-7), cavity left cover (5-8), cavity rear cover (5-9) and cavity upper cover (5-10) are assembled and installed into a sealed cavity; The output light of the LD laser tube (2-1) enters the first collimating lens (2-4) for collimation, reaches the filter (3-1) for wavelength adjustment after collimation, then passes through the first collimating lens (4-1) and the output coupling lens (4-3), and finally passes through the second collimating lens (4-4) to form a cat's eye output laser.

2. The interference filter type external cavity semiconductor laser according to claim 1, characterized in that The laser base (1), LD laser tube (2-1), LD pressure screw (2-3), first collimating lens (2-4), first collimating lens barrel (2-5), filter IF rotating barrel (3-2), first collimating lens barrel (4-2) and second collimating lens barrel (4-5) are all made of indium steel 4J36 material; the material of the heat sink (5-2) is brass.

3. The interference filter type external cavity semiconductor laser according to claim 1, characterized in that The length of the laser light source assembly (2) from the light output surface of the LD laser tube (2-1) to the incident end surface of the output coupling mirror (4-3), that is, the cat's eye cavity length, is controlled at 30 mm.

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