CN116544787A - Narrow linewidth stable spectrum semiconductor laser - Google Patents
Narrow linewidth stable spectrum semiconductor laser Download PDFInfo
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- CN116544787A CN116544787A CN202310575000.3A CN202310575000A CN116544787A CN 116544787 A CN116544787 A CN 116544787A CN 202310575000 A CN202310575000 A CN 202310575000A CN 116544787 A CN116544787 A CN 116544787A
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- laser
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- bragg grating
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- 239000004065 semiconductor Substances 0.000 title claims abstract description 52
- 238000001228 spectrum Methods 0.000 title claims abstract description 18
- 238000007493 shaping process Methods 0.000 claims description 18
- 230000003287 optical effect Effects 0.000 claims description 15
- 230000005540 biological transmission Effects 0.000 claims description 8
- 238000000034 method Methods 0.000 claims description 8
- 239000011248 coating agent Substances 0.000 claims description 3
- 238000000576 coating method Methods 0.000 claims description 3
- 238000005086 pumping Methods 0.000 abstract description 12
- 230000008878 coupling Effects 0.000 abstract description 2
- 238000010168 coupling process Methods 0.000 abstract description 2
- 238000005859 coupling reaction Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 3
- 238000002834 transmittance Methods 0.000 description 3
- 238000000862 absorption spectrum Methods 0.000 description 2
- 230000001174 ascending effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000002310 reflectometry Methods 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 230000009471 action Effects 0.000 description 1
- 230000003321 amplification Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000007888 film coating Substances 0.000 description 1
- 238000009501 film coating Methods 0.000 description 1
- 238000005286 illumination Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000003199 nucleic acid amplification method Methods 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 239000006089 photosensitive glass Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
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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
- H01S5/40—Arrangement of two or more semiconductor lasers, not provided for in groups H01S5/02 - H01S5/30
- H01S5/4012—Beam combining, e.g. by the use of fibres, gratings, polarisers, prisms
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- 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
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A90/00—Technologies having an indirect contribution to adaptation to climate change
- Y02A90/10—Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
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- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Optics & Photonics (AREA)
- Semiconductor Lasers (AREA)
Abstract
The invention discloses a narrow linewidth stable spectrum semiconductor laser, which belongs to the technical field of semiconductor laser and solves the problems of low VBG diffraction efficiency, large central wavelength temperature drift and low pumping efficiency in the prior art. The invention adopts a folding type external cavity feedback structure, and reflects part of low-power laser to the volume Bragg grating VBG through the spectroscope, so that the temperature drift of the central wavelength is small while the linewidth of the laser is narrowed, the reliability is high, and the structure is applied to a coupling module of a plurality of semiconductor laser units, and the phenomenon of the temperature drift of the central wavelength after the plurality of laser units are irradiated to the volume Bragg grating is effectively solved, thereby ensuring the pumping efficiency of the laser to be high and the reliability to be high.
Description
Technical Field
The invention belongs to the technical field of semiconductor lasers, and particularly relates to a narrow-linewidth stable spectrum semiconductor laser.
Background
The single tube beam-combining semiconductor laser is widely used for laser illumination, laser processing, laser medical treatment and as pump light for pumping solid lasers, disc lasers, fiber lasers and the like because of the advantages of small volume, high efficiency, good reliability and the like. At present, the research focus of semiconductor lasers is focused on power and beam quality, but with the continuous expansion of applications, the spectral characteristics are increasingly important whether being used as a pumping source or directly applied as a light source. From the pumping perspective, a narrow linewidth stable spectrum means higher pumping efficiency, and from the direct application, more laser units are coupled in the same spectrum range, so that higher laser power and power density are more beneficial to obtain. The commercial semiconductor laser is used as a pumping source, and has the main problems that the typical spectrum width is usually 2-5 nm, the temperature drift phenomenon of the center wavelength is serious, and when the absorption spectrum of a working substance is very narrow, the pumping spectrum and the absorption spectrum cannot be strictly matched, so that the application cannot be directly carried out in the field, the spectrum width of the semiconductor laser must be narrowed by a technical means, and the center wavelength is well controlled.
The external cavity feedback structure based on the volume Bragg grating VBG can effectively narrow the line width of the free-running semiconductor laser, and mainly comprises a semiconductor laser chip, a beam shaping lens and the volume Bragg grating VBG, wherein the narrowing principle is as follows: the free-running semiconductor laser is collimated by the beam shaping lens and then is incident on the volume Bragg grating VBG, the front cavity surface anti-reflection semiconductor laser chip provides a gain medium and a rear cavity surface, the volume Bragg grating VBG is used as the front cavity surface of the resonant cavity, particle number inversion is realized under the action of electric excitation, the volume Bragg grating VBG feedback light is used as seed light, and laser is formed through resonance amplification output.
In the prior art, the volume Bragg grating VBG is placed in a main light path, the diffraction efficiency is usually 5-20%, the whole power of a semiconductor laser chip irradiates on the VBG, and because the VBG is made of photosensitive glass, the self diffraction wavelength drift can occur after high-power laser is absorbed, so that serious temperature drift phenomenon is generated at the laser center wavelength after line width is narrowed, and pumping efficiency is influenced.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a narrow linewidth stable spectrum semiconductor laser with high VBG diffraction efficiency, small center wavelength temperature drift and high pumping efficiency.
In order to achieve the technical purpose, the narrow linewidth spectrum-stabilizing semiconductor laser adopts the following technical scheme:
the utility model provides a steady spectrum semiconductor laser of narrow linewidth, includes laser shaping module, laser shaping module includes the semiconductor laser unit that sets gradually along the optical axis direction, fast axis collimating mirror and slow axis collimating mirror, fast axis collimating mirror is used for collimating the ascending divergence angle of fast axis, slow axis collimating mirror is used for collimating the ascending divergence angle of slow axis, slow axis collimating mirror rear end is equipped with the laser mirror that the slope set up, become 135 contained angles between laser mirror and the main light path, the laser mirror rear end is equipped with the spectroscope that the slope set up, become 45 contained angles between spectroscope mirror and the main light path, the spectroscope lateral part is equipped with volume Bragg grating VBG, the center normal of volume Bragg grating VBG is mutually perpendicular with the main light path.
Preferably, the number of the laser shaping modules is not less than 1, and when the number of the laser shaping modules is greater than 1, the plurality of groups of laser shaping modules are sequentially arranged from high to low along the main optical path according to a step method.
Preferably, the semiconductor laser unit is a single-tube laser with a single luminous point or a linear array laser with multiple luminous points.
Preferably, the spectral ratio of the coating film of the spectroscope is any value.
Preferably, the transmission power of the spectroscope is equal to or greater than 95%, and the power reflected to the volume Bragg grating VBG is equal to or less than 5%.
Compared with the prior art, the invention has the beneficial effects that:
the invention adopts a folding type external cavity feedback structure, and reflects part of low-power laser to the volume Bragg grating VBG through the spectroscope, so that the temperature drift of the central wavelength is small while the linewidth of the laser is narrowed, the reliability is high, and the structure is applied to a coupling module of a plurality of semiconductor laser units, and the phenomenon of the temperature drift of the central wavelength after the plurality of laser units are irradiated to the volume Bragg grating is effectively solved, thereby ensuring the pumping efficiency of the laser to be high and the reliability to be high.
Drawings
FIG. 1 is a schematic diagram of a prior art structure;
FIG. 2 is a schematic diagram of a structure of a second prior art;
FIG. 3 is a schematic view of a first embodiment of the present invention;
fig. 4 is a schematic structural diagram of a second embodiment of the present invention.
In the figure: 1. a semiconductor laser unit; 2. a fast axis collimator lens; 3. a slow axis collimating mirror; 4. a laser mirror; 5. a beam splitter; 6. and a volume Bragg grating VBG.
Detailed Description
The invention is further described below with reference to the drawings and detailed description:
as shown in fig. 1, a narrow linewidth semiconductor laser in the prior art includes a semiconductor laser unit, a fast axis collimating mirror and a slow axis collimating mirror, which are sequentially arranged along an optical axis, a laser reflecting mirror is obliquely arranged at the rear end of the slow axis collimating mirror, a body bragg grating VBG is arranged at the rear end of the laser reflecting mirror, the body bragg grating VBG is arranged along a main optical path, and the central normals of the semiconductor laser unit, the fast axis collimating mirror and the slow axis collimating mirror are perpendicular to the direction of the main optical path.
After a semiconductor laser unit in the laser emits light, laser is collimated by a fast axis collimating mirror to the divergence angle of the fast axis direction, then is collimated by a slow axis collimating mirror to the divergence angle of the slow axis direction, the collimated laser is incident on a laser reflecting mirror to change the laser transmission direction, and then is incident on a volume Bragg grating VBG to perform external cavity feedback, so that line width narrowing and center wavelength locking are realized, but the volume Bragg grating VBG in the laser is arranged in a main light path, along with the increase of working current, high-power laser can directly irradiate the volume Bragg grating VBG, the volume Bragg grating VBG absorbs heat to cause the center wavelength after external cavity feedback to drift, and the stability requirement of the center wavelength is difficult to realize.
As shown in fig. 2, the high-power semiconductor laser in the prior art comprises a plurality of groups of laser units which are sequentially arranged along a main light path, a volume bragg grating VBG is arranged at the rear end of each end laser unit, the volume bragg grating VBG is arranged along the direction of the main light path, each laser unit comprises a semiconductor laser unit, a fast axis collimating mirror and a slow axis collimating mirror which are sequentially arranged along an optical axis, a laser reflecting mirror which is obliquely arranged is arranged at the rear end of each slow axis collimating mirror, and the central normals of the semiconductor laser units, the fast axis collimating mirrors and the slow axis collimating mirrors are perpendicular to the main light path.
In order to obtain higher power laser output, the semiconductor laser is spatially combined, the semiconductor laser units are arranged by adopting a stepped reflector method, and are overlapped in the fast axis direction after being reflected by utilizing a laser reflector, so that a certain height difference is needed between the semiconductor laser units, namely, a mechanical workpiece is processed according to a set height difference by adopting a mechanical stepped method, and after the spatial beam combination, all laser is directly incident into a volume Bragg grating VBG for external cavity feedback, and spectrum is locked.
However, as the number of semiconductor laser units increases, the total laser power increases, and when the volume bragg grating VBG is placed on the main optical path, the stability of the center wavelength is more difficult to control, so that the laser is unfavorable for power expansion, and cannot achieve both high power output and stability of laser spectrum.
As shown in fig. 3-4, a narrow linewidth spectrum-stabilizing semiconductor laser comprises a laser shaping module, the laser shaping module comprises a semiconductor laser unit 1, a fast axis collimating mirror 2 and a slow axis collimating mirror 3 which are sequentially arranged along the optical axis direction, the semiconductor laser unit 1 is a single-tube laser with a single luminous point or a linear array laser with multiple luminous points, the fast axis collimating mirror 2 is used for collimating the divergence angle in the fast axis direction, the slow axis collimating mirror 3 is used for collimating the divergence angle in the slow axis direction, the rear end of the slow axis collimating mirror 3 is provided with a laser reflecting mirror 4 which is obliquely arranged, an included angle of 135 degrees is formed between the mirror surface of the laser reflecting mirror 4 and a main optical path, the rear end of the laser reflecting mirror 4 is provided with a spectroscope 5 which is obliquely arranged, an included angle of 45 degrees is formed between the mirror surface of the spectroscope 5 and the main optical path, the side part of the spectroscope 5 is provided with a volume bragg grating VBG6, the film coating splitting ratio of the spectroscope is an arbitrary value, the transmission power ratio is not smaller than or equal to 95%, the transmission power ratio of VBG is smaller than the normal power of the spectroscope VBG and the normal power of the VBG is smaller than the VBG and the VBG is smaller than the normal power of the VBG. When the number of the laser shaping modules is not less than 1, a plurality of groups of laser shaping modules are sequentially arranged from high to low along a main light route according to a step method.
According to the invention, after the semiconductor laser unit emits light, the divergence angle in the fast axis direction is collimated through the fast axis collimating mirror 2, then the divergence angle in the slow axis direction is collimated through the slow axis collimating mirror 3, the collimated laser is incident on the laser reflecting mirror 4, the transmission direction of the laser is changed by the laser reflecting mirror 4 and then is incident on the spectroscope 5, the low-power laser in a certain proportion is transmitted to the volume Bragg grating VBG6 for external cavity feedback, line width narrowing is realized, the center wavelength is locked, and as the transmission power of the spectroscope is equal to or less than 95%, the power ratio of the spectroscope reflected to the volume Bragg grating VBG is equal to or less than 5%, the main light path laser power is not influenced when the light with smaller power is incident on the volume Bragg grating VBG, compared with the diffraction efficiency of the volume Bragg grating VBG arranged on the main light path in the prior art, which is usually between 5 and 20%.
Example 1
As shown in fig. 3, taking a narrow linewidth semiconductor laser with a center wavelength of 976nm as an example, when the semiconductor laser unit is a single-tube laser, the unit output power is 15-30W, when the semiconductor laser unit is a linear array laser, the unit output power is 60-100W, laser emitted by the semiconductor laser unit is collimated by a fast axis collimator lens, the divergence angle in the fast axis direction is 60 °, then the divergence angle in the slow axis direction is collimated by a slow axis collimator lens, the slow axis divergence angle is 10 °, the collimated light after shaping is changed by 45 ° through a laser mirror optical path and then enters a spectroscope, the transmittance of a spectroscope coating film is set to 95%, the reflectance on a volume bragg grating VBG is 5%, and the power after light splitting is incident on the volume bragg grating VBG with a diffraction efficiency of 90-100%: the single-tube laser is 0.75-1.5W, and the linear array laser is 3-5W. From the power angle, compared with the traditional method that the laser is directly incident to the volume Bragg grating VBG, the incident laser power is obviously reduced, and the temperature rise of the corresponding volume Bragg grating VBG affected by laser is small, so that the temperature drift of the central wavelength after the feedback of the outer cavity is small, and the pumping efficiency is effectively improved.
Example 2
As shown in fig. 4, one difference from the embodiment is that: the number of the laser shaping modules is more than 1, and a plurality of groups of laser shaping modules are sequentially arranged from high to low along the main light route according to a step method.
The semiconductor laser units are arranged in a stepped mode by adopting a stepped reflector method, light beams are sequentially arranged from high to low along the fast axis direction after rotating for 45 degrees, so that high-power laser output is obtained, spectroscopes with different transmittances and reflectivities are selected according to the set total power after beam combination, if the total power of the beam combination is higher, the transmittance is set to be 99% transmission, and the reflectivity is set to be 1% reflection, so that when the number of the semiconductor laser units is increased and the total power of the laser is increased, the temperature rise is smaller when the number of the semiconductor laser units is increased, the volume Bragg grating VBG6 is arranged in a non-main light path of a folding cavity, the central wavelength temperature drift after feedback of an outer cavity is small, and the laser stability is good.
In summary, the present invention is not limited to the preferred embodiments, but includes all equivalent changes and modifications in shape, construction, characteristics and spirit according to the scope of the claims.
Claims (5)
1. The utility model provides a steady spectrum semiconductor laser of narrow linewidth, includes laser shaping module, its characterized in that: the laser shaping module comprises a semiconductor laser unit, a fast axis collimating mirror and a slow axis collimating mirror which are sequentially arranged along the direction of an optical axis, wherein the fast axis collimating mirror is used for collimating the divergence angle of the fast axis, the slow axis collimating mirror is used for collimating the divergence angle of the slow axis, the rear end of the slow axis collimating mirror is provided with a laser reflecting mirror which is obliquely arranged, an included angle of 135 degrees is formed between the mirror surface of the laser reflecting mirror and a main optical path, the rear end of the laser reflecting mirror is provided with a spectroscope which is obliquely arranged, an included angle of 45 degrees is formed between the mirror surface of the spectroscope and the main optical path, a volume Bragg grating VBG is arranged on the side part of the spectroscope, and the center normal of the volume Bragg grating VBG is perpendicular to the main optical path.
2. The narrow linewidth stabilized spectrum semiconductor laser of claim 1 wherein: and when the number of the laser shaping modules is not less than 1, the laser shaping modules are sequentially arranged from high to low along the main light route according to a step method.
3. The narrow linewidth stabilized spectrum semiconductor laser of claim 1 wherein: the semiconductor laser unit is a single-tube laser with a single luminous point or a linear array laser with multiple luminous points.
4. The narrow linewidth stabilized spectrum semiconductor laser of claim 1 wherein: the coating film splitting ratio of the spectroscope is any value.
5. The narrow linewidth stabilized spectrum semiconductor laser of claim 4 wherein: the transmission power of the spectroscope is equal to or greater than 95%, and the power reflected to the volume Bragg grating VBG is equal to or less than 5%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310575000.3A CN116544787A (en) | 2023-05-22 | 2023-05-22 | Narrow linewidth stable spectrum semiconductor laser |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310575000.3A CN116544787A (en) | 2023-05-22 | 2023-05-22 | Narrow linewidth stable spectrum semiconductor laser |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116544787A true CN116544787A (en) | 2023-08-04 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310575000.3A Pending CN116544787A (en) | 2023-05-22 | 2023-05-22 | Narrow linewidth stable spectrum semiconductor laser |
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|---|---|
| CN (1) | CN116544787A (en) |
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2023
- 2023-05-22 CN CN202310575000.3A patent/CN116544787A/en active Pending
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