CN116365351A - Narrow linewidth compression device for feedback self-adaptive adjustment of blue light semiconductor external cavity - Google Patents

Narrow linewidth compression device for feedback self-adaptive adjustment of blue light semiconductor external cavity Download PDF

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CN116365351A
CN116365351A CN202310397988.9A CN202310397988A CN116365351A CN 116365351 A CN116365351 A CN 116365351A CN 202310397988 A CN202310397988 A CN 202310397988A CN 116365351 A CN116365351 A CN 116365351A
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light
blazed grating
grating
output
blue
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王平
段长城
王修正
夏燃
肖瑜
徐刚
唐霞辉
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Huazhong University of Science and Technology
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/005—Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping
    • H01S5/0057—Optical components external to the laser cavity, specially adapted therefor, e.g. for homogenisation or merging of the beams or for manipulating laser pulses, e.g. pulse shaping for temporal shaping, e.g. pulse compression, frequency chirping
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
    • H01S5/068—Stabilisation of laser output parameters
    • H01S5/0683—Stabilisation of laser output parameters by monitoring the optical output parameters
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/06—Arrangements for controlling the laser output parameters, e.g. by operating on the active medium
    • H01S5/068—Stabilisation of laser output parameters
    • H01S5/0683—Stabilisation of laser output parameters by monitoring the optical output parameters
    • H01S5/06837—Stabilising otherwise than by an applied electric field or current, e.g. by controlling the temperature
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01S—DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL
    • H01S5/00—Semiconductor lasers
    • H01S5/10—Construction or shape of the optical resonator, e.g. extended or external cavity, coupled cavities, bent-guide, varying width, thickness or composition of the active region
    • H01S5/14—External cavity lasers
    • H01S5/141—External cavity lasers using a wavelength selective device, e.g. a grating or etalon
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/10—Nuclear fusion reactors

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  • Semiconductor Lasers (AREA)

Abstract

The invention discloses a narrow linewidth compression device for feedback self-adaptive adjustment of a blue light semiconductor external cavity. The device comprises: the system comprises a collimation system, a reflection array, a line width compression system and a detection feedback system; the collimation system comprises a blue light single tube array and a fast and slow axis collimation lens group; the reflection array reflects the blue laser beams output after passing through the fast and slow axis collimating lens group and then makes the blue laser beams incident on the blazed grating; the linewidth compression system comprises a blazed grating and an output coupling mirror; the blazed grating is arranged on the grating setting plate of the self-adaptive adjusting frame; the self-adaptive adjusting frame also comprises an adjusting column and a positioning rod, and the pitch angle of the blazed grating is adjusted in multiple directions; the output coupling mirror couples a plurality of blue laser beams after diffraction of the blazed grating into an output beam; the detection feedback system detects the power, wavelength and line width of the output light beam, and adjusts the self-adaptive adjusting frame so as to adjust the pitch angle of the blazed grating. The semiconductor blue light output with high power, narrow linewidth, tunability, high stability and high beam quality is realized.

Description

Narrow linewidth compression device for feedback self-adaptive adjustment of blue light semiconductor external cavity
Technical Field
The invention belongs to the technical field of semiconductor laser grating external cavities, and particularly relates to a narrow linewidth compression device for feedback self-adaptive adjustment of a blue light semiconductor external cavity.
Background
The application range of the semiconductor laser covers the whole field of optoelectronics, and the semiconductor laser has become a core technology of the present-day optoelectronics science. The semiconductor laser has the advantages of small volume, simple structure, low input energy, long service life, easy modulation, low price and the like, so that the semiconductor laser is widely applied to the field of photoelectrons at present and has been highly valued in countries around the world. However, with the improvement of the requirements of people on the quality of the light beam, the defects of small output power (< 30W), wider line width (> 1 nm), poor light beam quality (large difference of the light beam quality of the fast axis and the slow axis), low power density and the like of the semiconductor laser unit lead to the difficulty of being directly applied as a crystal pumping light source. Therefore, how to obtain semiconductor laser output with high power, narrow linewidth, tunability, high stability and high beam quality at the same time has become a serious bottleneck technical problem internationally.
In recent years, in order to study blue semiconductor laser output with narrow linewidth, researchers at home and abroad have reported a few semiconductor lasers using different gratings as external cavity feedback elements. Compared with distributed Bragg reflection (DBR, distributed Bragg Reflector) and distributed feedback (DFB, distributed Feed Back) lasers, the grating external cavity type semiconductor laser has simple mode and high frequency stability, and has important application in a plurality of fields such as laser processing, deep ultraviolet frequency multiplication, gas detection, large-capacity information storage and the like. The traditional external cavity is mainly divided into two structures, namely Littrow and Littman: the Littrow structure uses first-order diffraction light of the grating as output light, zero-order diffraction light as feedback light, and the feedback light is injected into an LD active region, so that a mode selected by the grating has advantages in competition; the Littman structure uses the zero-order diffraction light of the grating as output light, the first-order diffraction light is returned to the grating through a reflector, and the re-diffracted first-order diffraction light is feedback light.
However, in the two traditional structures, a holographic diffraction grating is mostly used as a light splitting feedback device, but the anti-damage threshold of the plane reflection type holographic diffraction grating is low, high-power blue light output cannot be realized, and in the light beam output process, the blue light output stability is poor due to the influence of factors such as temperature, adjustment errors and the like. Therefore, the problems that the quality of the existing blue light single tube/array light beam is poor, the damage resistance threshold of the grating used by the existing grating external cavity structure is low, high-power blue light output cannot be realized, and the stability of the output light beam is poor exist.
Disclosure of Invention
Aiming at the defects of the related art, the invention aims to provide a narrow linewidth compression device for feedback self-adaptive adjustment of a blue light semiconductor outer cavity, and aims to solve the problems that the quality of the existing blue light single tube/array light beam is poor, the damage resistance threshold of the grating used by the existing grating outer cavity structure is low, high-power blue light output cannot be realized, and the stability of the output light beam is poor.
In order to achieve the above object, the present invention provides a narrow linewidth compression device for feedback adaptive adjustment of a blue semiconductor external cavity, comprising: the system comprises a collimation system, a reflection array, a line width compression system and a detection feedback system;
the collimating system comprises a blue light single-tube array and a fast-slow axis collimating lens group, wherein the blue light single-tube array is used for exciting equidistant and equal-power blue light laser beams, and the fast-slow axis collimating lens group is used for collimating the blue light laser beams and reducing the divergence angle of the blue light laser beams;
the reflection array is used for reflecting the blue laser beams output after passing through the fast and slow axis collimating lens group and then making the blue laser beams incident on the blazed grating;
the linewidth compression system comprises a blazed grating and an output coupling mirror; the blazed grating is used for compressing the line width of an incident blue laser beam and is arranged on a grating arranging plate of the self-adaptive adjusting frame; the self-adaptive adjusting frame further comprises adjusting columns arranged at four corners of the grating setting plate and a positioning rod arranged at the center of the grating setting plate, wherein the adjusting columns and the positioning rod are used for adjusting pitch angles of the blazed grating in multiple directions so that the incident angle of an incident blue laser beam meets the maximum efficiency diffraction angle of the blazed grating; the output coupling mirror is used for coupling a plurality of blue laser beams diffracted by the blazed grating into output beams;
the detection feedback system is used for detecting the power, wavelength and line width of the output light beam, carrying out data analysis, and controlling the self-adaptive adjusting frame according to the analysis result so as to adjust the pitch angle of the blazed grating in multiple directions.
Optionally, the adaptive adjusting frame further comprises a bearing shaft;
the adjusting column is connected with the bearing shaft through a lever;
one end of the positioning rod is arranged on the bearing shaft, and the other end of the positioning rod is arranged at the center of the grating placement plate through a hinge and is used for enabling the position of the blazed grating, into which the light beam is shot, to be always unchanged when the angle of the blazed grating is adjusted;
the bearing shaft is connected with the base through the main support, the base is connected with the detection feedback system through a first control line, and the first control line is used for transmitting control signals of the detection feedback system to the bearing shaft for control and can also control the base to move on the sliding rail.
Optionally, the detection feedback system comprises a power detector, a wavelength detector and a line width detector which are respectively connected with the first half mirror, the second half mirror and the third half mirror, and an upper computer which is connected with the power detector, the wavelength detector and the line width detector;
the output light beam sequentially passes through the first half-mirror, the second half-mirror and the third half-mirror; the light beam reflected by the first half-transmitting half-reflecting mirror is received by the power detector to obtain a power image; the light beam reflected by the second half-mirror is received by the wavelength detector to obtain a wavelength image; the light beam reflected by the third half mirror is received by the line width detector to obtain a line width image;
the upper computer receives the power image, the wavelength image and the line width image, obtains the adjustment amount after processing, and transmits the adjustment amount to the self-adaptive adjusting frame through the first control line.
Optionally, the narrow linewidth compression device further comprises a water cooling system; the water cooling system comprises a cold water pipe and a water cooler;
the water cooler is connected with the blue light single tube array and the water inlet and the water outlet on the self-adaptive adjusting frame respectively through the cold water pipe, the water cooler is also connected with the upper computer through the second control line, and the water cooler is used for radiating the blue light single tube array and the blazed grating arranged on the self-adaptive adjusting frame.
Optionally, the blue laser beam incident to the blazed grating is diffracted, the negative first-order diffracted light is separated from the system, the positive first-order diffracted light passes through the output coupling mirror, the transmitted light is output light, the reflected light is feedback light, the feedback light is reflected to form secondary diffraction through the blazed grating, and the secondary diffraction is returned to the active area injected into the blue single-tube array through the original light path, and line width compression is performed again.
Optionally, the narrow linewidth compressing device further includes a focusing lens disposed at the rear of the third half mirror along the light path direction, and configured to converge the light beam transmitted by the third half mirror and then make the light beam incident into the optical fiber.
Optionally, the central axes of the optical lenses in the narrow linewidth compression device are coincident with the central axes of the light beams, and are coated with blue light antireflection films.
Optionally, the narrow linewidth compressing device further comprises a beam expanding system;
the beam expanding system comprises two convex lenses, and the beam expanding system is arranged behind the collimation system along the direction of the light path and is used for re-collimating the blue laser beam after being collimated by the fast axis and the slow axis and compressing the divergence angle.
In general, the above technical solutions conceived by the present invention, compared with the prior art, enable the following beneficial effects to be obtained:
1. the narrow linewidth compression device for the feedback self-adaptive adjustment of the blue light semiconductor outer cavity uses the blazed grating as an optical feedback element of the laser outer cavity, and the first-order diffraction efficiency of the blazed grating to the blazed wavelength can reach more than 90%, so that the laser output efficiency can be greatly improved, and the high-power laser output is realized.
2. According to the narrow linewidth compression device for the feedback self-adaptive adjustment of the blue light semiconductor outer cavity, the blazed grating is arranged on the grating arranging plate of the self-adaptive adjusting frame, and the self-adaptive adjusting frame can be adjusted according to the analysis result of the detection feedback system, so that the pitch angle of the blazed grating can be adjusted in multiple directions, and the light beams with target output power, wavelength and linewidth can be obtained.
3. In the blue light semiconductor external cavity structure provided by the invention, the feedback light beam injected into the blue light single-tube array passes through twice diffraction dispersion on the blazed grating before returning, so that the light with a narrower wavelength range is fed back to the gain device, and the line width of the output light beam becomes narrower.
4. The invention can monitor the characteristic parameters of energy, wavelength, line width and the like of the output light beam in real time through the detection feedback system, and adjust the temperature of the water cooling system, the current of the blue light single tube array and the pitching angle of the blazed grating in real time after the processing of the upper computer, thereby greatly improving the stability of the output light beam.
Drawings
Fig. 1 is a schematic structural diagram of a narrow linewidth compression device with feedback adaptive adjustment for a blue semiconductor external cavity according to an embodiment of the present invention;
fig. 2 is a schematic diagram of collimation of a single blue semiconductor laser tube according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of diffraction characteristics of a blazed grating according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a feedback system for detecting an output beam according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a structure of a blazed grating angle adaptive adjustment device according to an embodiment of the present invention;
fig. 6 is a schematic diagram of spatial beam combination of a single-tube blue-light array according to an embodiment of the present invention;
fig. 7 is a schematic diagram of coupling-out of a blue light external cavity according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. In addition, the technical features of the embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.
The description of the contents of the above embodiment will be given below in connection with a preferred embodiment.
As shown in fig. 1, a narrow linewidth compression device for feedback adaptive adjustment of a blue light semiconductor external cavity includes: the system comprises a collimation system, a reflection array, a line width compression system and a detection feedback system;
the collimation system comprises a blue light single tube array 3 and a fast and slow axis collimation lens group, wherein the blue light single tube array 3 is used for exciting equidistant and equal-power blue light laser beams, and the fast and slow axis collimation lens group is used for collimating the blue light laser beams and reducing the divergence angle of the blue light laser beams;
the reflection array 10 is used for reflecting the blue laser beams output after passing through the fast and slow axis collimating lens group and then making the reflected blue laser beams incident on the blazed grating 13;
the linewidth compression system comprises a blazed grating 13 and an output coupling mirror 18; the blazed grating 13 is used for compressing the line width of an incident blue laser beam, the blazed grating 13 is arranged on a grating arranging plate 30 of the adaptive adjusting frame 14, the adaptive adjusting frame 14 further comprises adjusting columns (31, 32, 33 and 34) arranged at four corners of the grating arranging plate 30, and a positioning rod 39 arranged at the center of the grating arranging plate 30, and the adjusting columns (31, 32, 33 and 34) and the positioning rod 39 are used for adjusting the pitch angle of the blazed grating 13 so that the incident angle of the incident blue laser beam meets the maximum efficiency diffraction angle of the blazed grating 13; the output coupling mirror 18 is configured to couple the plurality of blue laser beams diffracted by the blazed grating 13 into an output beam;
the detection feedback system is used for detecting the power, wavelength and line width of the output light beam, performing data analysis, and controlling the self-adaptive adjusting frame 14 according to the analysis result so as to adjust the pitch angle of the blazed grating 13.
As shown in fig. 1, in the narrow linewidth compression device with feedback adaptive adjustment of the blue light semiconductor body in this embodiment, high quality beam combination, linewidth compression and real-time control of the output beam of the blue light single tube array 3 are realized by using the grating system constructed by the blazed grating 13. The collimation system comprises a blue light single tube array and a fast and slow axis collimation lens group, the upper computer 1 supplies power to the blue light single tube array 3 through a third control line 2 and controls current output in real time, the blue light single tube array 3 is formed by arranging a plurality of semiconductor laser single tubes 4 on a base according to the array, the semiconductor laser single tubes 4 all emit equidistant and equal-power blue laser beams under the action of current, and the blue laser beams are collimated through the semiconductor laser collimation system formed by the fast axis collimation lens 5 and the slow axis collimation lens 6 and reduce the divergence angle of the blue laser beams. As shown in fig. 2, the blue laser beam excited by the semiconductor laser single tube 4 has different divergence angles in the fast axis and the slow axis directions, and is difficult to be collimated by a single collimator, in this embodiment, after the semiconductor laser beam excited by the semiconductor laser single tube 4 exits, the fast axis and the slow axis of the beam are respectively collimated by the fast axis collimator 5 and the slow axis collimator 6, so that the divergence angles in the two directions are reduced to less than 0.01 ° and the beam quality of the blue laser beam is ensured in the subsequent transmission process.
The blue laser beam passing through the collimation system is incident on a reflection array 10 formed by a series of reflectors, is incident on a linewidth compression system after being reflected, is particularly incident on a blazed grating 13, the incident angle meets the maximum efficiency diffraction angle of the blazed grating 13, the highest-efficiency positive-order diffraction light obtained after being diffracted by the blazed grating 13 is output to an output coupling mirror 18, and the diffracted blue laser beam is coupled and output through the output coupling mirror 18. Wherein the blazed grating 13 is arranged on the grating arrangement plate 30 of the adaptive adjusting frame 14; the adaptive adjusting frame 14 further comprises adjusting posts (31, 32, 33 and 34) arranged at four corners of the grating arrangement plate 30 and a positioning rod 39 arranged at the center of the grating arrangement plate 30 for multi-directionally and multi-angle adjusting the pitch angle of the blazed grating 13, so that the incident angle of the incident blue laser beam meets the maximum efficient diffraction angle of the blazed grating 13, and tuning of the output wavelength is realized by controlling the angle of the blazed grating 13. In this embodiment, the output coupling mirror 18 selects the output coupling mirror 18 with a transmittance of 70%, 30% of the light beam returns along the original optical path, and 70% of the light beam is transmitted to form an output light beam.
As shown in fig. 3, diffraction characteristics of the blazed grating 13 are analyzed in addition, and the first order diffraction rate and the incidence angle of the blazed grating 13 are both related to the wavelength of incident light, assuming that the wavelength of incident light is λ, the incident angle of light is a, the blazed angle of grating is b, the number of grating lines is d, and the reflectivity of the grating is R. The diffraction efficiency of the blazed grating 13 can be obtained as follows:
Figure BDA0004178278700000071
wherein N is the number of grating lines,
Figure BDA0004178278700000072
when the incident angle a is equal to the blaze angle b, it is possible to output in the direction of the diffraction angle c of the highest efficiency.
Further, in this process, the position of the corresponding mirror on the reflective array 10 needs to be adjusted, so that the optical path length of each blue laser beam excited by the semiconductor laser single tube 4 from the process of emitting to the blazed grating 13 is strictly equal, and the beam combination effect of the subsequent beams and the feedback accuracy of the detection feedback system are guaranteed.
As shown in fig. 4, the output light beam sequentially passes through a first half mirror 19, a second half mirror 22 and a third half mirror 25, the transmittance of which is 1% in the detection feedback system, the reflected three light beams are respectively received by a power detector 20, a wavelength detector 23 and a linewidth detector 26, a power image, a wavelength image and a linewidth image of the output light beam are obtained, the power image, the wavelength image and the linewidth image of the output light beam are respectively collected to the upper computer 1 through a first network line 21, a second network line 24 and a third network line 27, the upper computer 1 analyzes the received data through calculation, the current of the blue light single-tube array 3 and the angle of the blazed grating 13 are respectively adjusted through a third control line 2 and the first control line 17, the power of the output light beam is adjusted through adjusting the current of the blue light single-tube array 3, and the pitch angles of the blazed gratings 13 under the matching currents of different blue light single-tube arrays 3 are tuned, so that the effect of stabilizing the power, the wavelength and the linewidth of the output light beam is achieved. Finally, the light beam transmitted through the third half mirror 25 is focused by the focusing mirror 28 and then is incident on the optical fiber 29 to be output. Wherein the rest of the optical elements are fixed in optimal positions and angles, except for the blazed grating 13 and the adaptive tuning frame 14.
In the technical scheme of the invention, the blazed grating is adopted as the optical feedback element of the laser outer cavity, and the first-order diffraction efficiency of the blazed grating to the blazed wavelength can reach more than 90%, so that the laser output efficiency can be greatly improved, and the high-power laser output can be realized; the self-adaptive adjusting frame is adopted to place the blazed grating, and the self-adaptive adjustment can be carried out according to the power image, the wavelength image and the comparison analysis result of the linewidth image and preset data of the output light beam detected by the detection feedback system, so that the pitch angle of the blazed grating is adjusted in multiple directions, and the angle of the light beam incident to the blazed grating is the optimal incidence angle; the detection feedback system can also control the current of the blue light single tube array so as to obtain the light beams with target output power, wavelength and line width.
The energy concentration of the blazed grating in the first-order diffraction light and the excellent compression capability of the grating outer cavity to the line width are combined, and the grating angle, the water cooling temperature and the single-tube current are adaptively adjusted through output feedback information, so that the problems that the quality of an existing blue light single tube/array light beam is poor, the damage resistance threshold of the grating used by an existing grating outer cavity structure is low, high-power blue light output cannot be achieved, and the stability of an output light beam is poor are solved. The wavelength locking and linewidth compression of the output light beam of the high-power blue semiconductor laser are realized, the output power and the light beam quality are improved, and the semiconductor blue light output with high power, narrow linewidth, tunability, high stability and high light beam quality is obtained.
On the basis of the above embodiment, as shown in fig. 5, optionally, the adaptive adjustment frame 14 further includes a bearing shaft 35;
the adjusting columns (31, 32, 33 and 34) are connected to the bearing shaft 35 by means of lever bars (not shown);
one end of the positioning rod 39 is arranged on the bearing shaft 35, and the other end of the positioning rod 39 is arranged at the center of the grating placement plate 30 through a hinge 12, so that the position of the blazed grating 13 where the light beam is incident is always kept unchanged when the angle of the blazed grating 13 is adjusted;
the bearing shaft 35 is connected with the base 37 through the main bracket 36, the base 37 is connected with the detection feedback system through the first control line 17, the first control line 17 is used for transmitting a control signal of the detection feedback system to the bearing shaft 35 for control, and the base 37 can be controlled to move on the sliding rail 38.
As shown in fig. 7, when the blue laser beam is incident on the blazed grating 13, the incident direction is almost perpendicular to the blazed grating 13, the zero-order diffracted light returns to the active area of the blue single-tube array along the optical path, the positive-order diffracted light containing main energy is incident on the output coupling mirror 18, the negative-order diffracted light containing a small amount of energy is separated from the system, the blazed grating 13 can be finely adjusted at multiple angles through the adaptive adjusting frame 14, so that the main wavelength in the feedback light is ensured to be the target wavelength, and the system optical path direction is basically unchanged when the angle of the blazed grating 13 is adjusted by the adaptive adjusting frame 14 due to the existence of the hinge 12, so that the stability of the optical path output in the tuning process is ensured. Further, the base 37 can slightly move on the sliding rail 38, so as to meet the multi-directional requirement of angle adjustment of the blazed grating 13.
On the basis of the above embodiment, optionally, the narrow linewidth compression device further includes a water cooling system; the water cooling system comprises a cold water pipe and a water cooler 9;
the water cooler 9 is connected with the blue light single tube array 3 and the water inlet and the water outlet on the self-adaptive adjusting frame 14 respectively through the cold water pipe, the water cooler 9 is also connected with the upper computer 1 through the second control line 11, and the water cooler 9 is used for radiating the blue light single tube array 3 and the blazed grating arranged on the self-adaptive adjusting frame 14.
As shown in fig. 6, a water inlet 7 and a water outlet 8 are arranged on the base of the blue light single tube array 3, a water cooler 9 inputs working liquid into the base of the blue light single tube array 3 from the water inlet 7 through a cold water pipe, and then flows back to the water cooler 9 from the cold water pipe of the water outlet 8 for water cooling circulation, so that the temperature of the semiconductor laser single tube 4 on the blue light single tube array 3 is controlled, and the wavelength stability of the blue light laser beam in the operation process is ensured. The grating setting plate 30 of the self-adaptive adjusting frame 14 is provided with a water inlet 15 and a water outlet 16, which are used for carrying out water cooling circulation on the grating setting plate 30 and maintaining the stable temperature of the blazed grating 13. The upper computer 1 controls the water cooler 9 through the second control line 11, and realizes real-time temperature control of the blue light single-tube array 3 and the blazed grating 13 through outputting feedback information.
As shown in fig. 7, alternatively, the blue laser beam incident on the blazed grating 13 is diffracted, the negative-order diffracted light is separated from the system, the positive-order diffracted light passes through the output coupling mirror, the transmitted light is output light, the reflected light is feedback light, the feedback light is reflected to form secondary diffraction through the blazed grating 13, and the secondary diffraction is returned to the active area of the blue single tube array 3 through the original optical path, and the linewidth compression is performed again.
When the blue laser beam is incident on the blazed grating 13, the incident direction is almost perpendicular to the blazed grating 13, the zero-order diffraction light returns to the single-tube active region along the light path, the positive-order diffraction light containing main energy is incident on the output coupling mirror 18, and the negative-order diffraction light containing little energy is separated from the system. The positive-order diffraction light with extremely high energy ratio is incident on the output coupling mirror 18 with 70% transmittance, wherein 70% of light beam energy is taken as output light to pass through the output coupling mirror, 30% of light beam energy is taken as reflected light to be reflected back to the blazed grating 13, and feedback light formed after re-diffraction can sequentially pass through the reflection array 10, the slow-axis collimating mirror 6 and the fast-axis collimating mirror 5 along an original light path to return to an active area of the semiconductor laser single tube 4, so that gain competition of each mode in the active area is affected, and the feedback light beam can further compress the line width through a double diffraction process, so that the feedback light beam wavelength range is extremely narrow, and wavelength selection and line width compression can be realized by adjusting the pitch angle of the blazed grating 13.
Further, on the basis of the above embodiment, the selection of the line width and the power of the output beam can also be achieved by adjusting the transmittance of the output coupling mirror 18.
The structure of the narrow linewidth compression device can be suitable for any wave band, and only the blazed grating and the lens parameters are matched again corresponding to different wavelengths, so that the whole structure is not changed.
Optionally, the central axes of the optical lenses in the narrow linewidth compression device are coincident with the central axes of the light beams, and are coated with blue light antireflection films.
The central axis of the optical lens is overlapped with the central axis of the light beam, so that the parallel output of the light path is ensured, and the output efficiency is improved through the antireflection film coated with blue light.
Optionally, the narrow linewidth compressing device further comprises a beam expanding system;
the beam expanding system comprises two convex lenses, and the beam expanding system is arranged behind the collimation system along the direction of the light path and is used for carrying out beam expanding on the blue laser beam collimated by the fast axis and the slow axis and then carrying out collimation again so as to further compress the divergence angle.
It will be readily appreciated by those skilled in the art that the foregoing description is merely a preferred embodiment of the invention and is not intended to limit the invention, but any modifications, equivalents, improvements or alternatives falling within the spirit and principles of the invention are intended to be included within the scope of the invention.

Claims (8)

1. The utility model provides a blue light semiconductor external cavity feedback self-adaptation adjusts narrow linewidth compression device which characterized in that includes: the system comprises a collimation system, a reflection array, a line width compression system and a detection feedback system;
the collimating system comprises a blue light single-tube array and a fast-slow axis collimating lens group, wherein the blue light single-tube array is used for exciting equidistant and equal-power blue light laser beams, and the fast-slow axis collimating lens group is used for collimating the blue light laser beams and reducing the divergence angle of the blue light laser beams;
the reflection array is used for reflecting the blue laser beams output after passing through the fast and slow axis collimating lens group and then making the blue laser beams incident on the blazed grating;
the linewidth compression system comprises a blazed grating and an output coupling mirror; the blazed grating is used for compressing the line width of an incident blue laser beam and is arranged on a grating arranging plate of the self-adaptive adjusting frame; the self-adaptive adjusting frame further comprises adjusting columns arranged at four corners of the grating setting plate and a positioning rod arranged at the center of the grating setting plate, wherein the adjusting columns and the positioning rod are used for adjusting pitch angles of the blazed grating in multiple directions so that the incident angle of an incident blue laser beam meets the maximum efficiency diffraction angle of the blazed grating; the output coupling mirror is used for coupling a plurality of blue laser beams diffracted by the blazed grating into output beams;
the detection feedback system is used for detecting the power, wavelength and line width of the output light beam, carrying out data analysis, and controlling the self-adaptive adjusting frame according to the analysis result so as to adjust the pitch angle of the blazed grating in multiple directions.
2. The narrow linewidth compression apparatus as recited in claim 1 wherein the adaptive tuning frame further comprises a load bearing shaft;
the adjusting column is connected with the bearing shaft through a lever;
one end of the positioning rod is arranged on the bearing shaft, and the other end of the positioning rod is arranged at the center of the grating placement plate through a hinge and is used for enabling the position of the blazed grating, into which the light beam is shot, to be always unchanged when the angle of the blazed grating is adjusted;
the bearing shaft is connected with the base through the main support, the base is connected with the detection feedback system through a first control line, and the first control line is used for transmitting control signals of the detection feedback system to the bearing shaft for control and controlling the base to move on the sliding rail.
3. The narrow linewidth compressing apparatus as recited in claim 2 wherein the detection feedback system comprises a power meter, a wavelength meter and a linewidth meter respectively connected to the first half mirror, the second half mirror and the third half mirror, and an upper computer connected to the power meter, the wavelength meter and the linewidth meter;
the output light beam sequentially passes through the first half-mirror, the second half-mirror and the third half-mirror; the light beam reflected by the first half-transmitting half-reflecting mirror is received by the power detector to obtain a power image; the light beam reflected by the second half-mirror is received by the wavelength detector to obtain a wavelength image; the light beam reflected by the third half mirror is received by the line width detector to obtain a line width image;
the upper computer receives the power image, the wavelength image and the line width image, obtains the adjustment amount after processing, and transmits the adjustment amount to the self-adaptive adjusting frame through the first control line.
4. The narrow linewidth compression apparatus as recited in claim 3 wherein said narrow linewidth compression apparatus further comprises a water cooling system; the water cooling system comprises a cold water pipe and a water cooler;
the water cooler is connected with the blue light single tube array and the water inlet and the water outlet on the self-adaptive adjusting frame respectively through the cold water pipe, the water cooler is also connected with the upper computer through the second control line, and the water cooler is used for radiating the blue light single tube array and the blazed grating arranged on the self-adaptive adjusting frame.
5. The narrow linewidth compressing apparatus as recited in claim 1 wherein the blue laser beam incident on the blazed grating is diffracted, the negative first order diffracted light is released from the system, the positive first order diffracted light is passed through the output coupling mirror, wherein the transmitted light is output light, the reflected light is feedback light, the feedback light is reflected to form secondary diffraction through the blazed grating, and is returned to the active region of the blue single tube array through the original optical path, and linewidth compression is performed again.
6. The narrow linewidth compressing apparatus as recited in claim 3 further comprising a focusing mirror disposed behind the third half mirror in the direction of the optical path for converging the light beams transmitted by the third half mirror and then incident into the optical fiber.
7. The narrow linewidth compressing apparatus as recited in claim 6 wherein each optical lens in the narrow linewidth compressing apparatus has a central axis coincident with the central axis of the light beam and is coated with an antireflection film for blue light.
8. The narrow linewidth compression apparatus as recited in claim 1 wherein the narrow linewidth compression apparatus further comprises a beam expanding system;
the beam expanding system comprises two convex lenses, and the beam expanding system is arranged behind the collimation system along the direction of the light path and is used for re-collimating the blue laser beam after being collimated by the fast axis and the slow axis and compressing the divergence angle.
CN202310397988.9A 2023-04-14 2023-04-14 Narrow linewidth compression device for feedback self-adaptive adjustment of blue light semiconductor external cavity Pending CN116365351A (en)

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CN202310397988.9A CN116365351A (en) 2023-04-14 2023-04-14 Narrow linewidth compression device for feedback self-adaptive adjustment of blue light semiconductor external cavity

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CN202310397988.9A CN116365351A (en) 2023-04-14 2023-04-14 Narrow linewidth compression device for feedback self-adaptive adjustment of blue light semiconductor external cavity

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