CN117613655A - Wide tuning laser based on saturable absorber - Google Patents
Wide tuning laser based on saturable absorber Download PDFInfo
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- CN117613655A CN117613655A CN202311489468.7A CN202311489468A CN117613655A CN 117613655 A CN117613655 A CN 117613655A CN 202311489468 A CN202311489468 A CN 202311489468A CN 117613655 A CN117613655 A CN 117613655A
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- optical fiber
- polarization
- saturable absorber
- polarization maintaining
- laser
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- 239000006096 absorbing agent Substances 0.000 title claims abstract description 40
- 230000010287 polarization Effects 0.000 claims abstract description 91
- 239000013307 optical fiber Substances 0.000 claims abstract description 76
- 230000003595 spectral effect Effects 0.000 claims abstract description 26
- 230000003287 optical effect Effects 0.000 claims abstract description 20
- 238000001228 spectrum Methods 0.000 claims abstract description 15
- 238000005086 pumping Methods 0.000 claims abstract description 3
- 239000000835 fiber Substances 0.000 claims description 39
- 230000001419 dependent effect Effects 0.000 claims description 14
- 238000000034 method Methods 0.000 claims description 5
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 3
- 238000000926 separation method Methods 0.000 claims description 3
- 239000000126 substance Substances 0.000 claims description 3
- 238000007740 vapor deposition Methods 0.000 claims description 3
- 230000008878 coupling Effects 0.000 claims description 2
- 238000010168 coupling process Methods 0.000 claims description 2
- 238000005859 coupling reaction Methods 0.000 claims description 2
- 150000002910 rare earth metals Chemical class 0.000 claims description 2
- 238000010079 rubber tapping Methods 0.000 claims description 2
- 238000013461 design Methods 0.000 abstract description 2
- 230000005540 biological transmission Effects 0.000 description 4
- 239000006185 dispersion Substances 0.000 description 2
- 230000010363 phase shift Effects 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000001902 propagating effect Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 229910052691 Erbium Inorganic materials 0.000 description 1
- 229910052769 Ytterbium Inorganic materials 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000007123 defense Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000000411 transmission spectrum Methods 0.000 description 1
- NAWDYIZEMPQZHO-UHFFFAOYSA-N ytterbium Chemical compound [Yb] NAWDYIZEMPQZHO-UHFFFAOYSA-N 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
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/11—Mode locking; Q-switching; Other giant-pulse techniques, e.g. cavity dumping
- H01S3/1106—Mode locking
- H01S3/1112—Passive mode locking
- H01S3/1115—Passive mode locking using intracavity saturable absorbers
- H01S3/1118—Semiconductor saturable absorbers, e.g. semiconductor saturable absorber mirrors [SESAMs]; Solid-state saturable absorbers, e.g. carbon nanotube [CNT] based
-
- 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
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/05—Construction or shape of optical resonators; Accommodation of active medium therein; Shape of active medium
- H01S3/06—Construction or shape of active medium
- H01S3/063—Waveguide lasers, i.e. whereby the dimensions of the waveguide are of the order of the light wavelength
- H01S3/067—Fibre lasers
- H01S3/06708—Constructional details of the fibre, e.g. compositions, cross-section, shape or tapering
- H01S3/06712—Polarising fibre; Polariser
-
- 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
- H01S3/00—Lasers, i.e. devices using stimulated emission of electromagnetic radiation in the infrared, visible or ultraviolet wave range
- H01S3/10—Controlling the intensity, frequency, phase, polarisation or direction of the emitted radiation, e.g. switching, gating, modulating or demodulating
- H01S3/10061—Polarization control
Abstract
The invention discloses a wide tuning laser based on a saturable absorber, which relates to the technical field of laser, and comprises a pumping source, a wavelength division multiplexer, a gain optical fiber, a saturable absorber, a polarization-related isolator, an optical fiber spectrum filter, an optical coupler and a second polarization controller, wherein the wavelength division multiplexer, the gain optical fiber, the saturable absorber and the optical fiber spectrum filter form an annular cavity light path; the optical fiber spectrum filter comprises a first polarizer, a second polarizer, a standard single-mode optical fiber, a first polarization controller, a first polarization maintaining optical fiber and a second polarization maintaining optical fiber, wherein the first polarization controller is arranged on the standard single-mode optical fiber between the first polarization maintaining optical fiber and the second polarization maintaining optical fiber. The invention utilizes the filter design based on the optical fiber, can realize adjustable spectral bandwidth under the principle of birefringence compensation based on the polarization maintaining optical fiber, and can generate unique laser modes with different output spectral shapes and pulse evolution.
Description
Technical Field
The invention relates to the technical field of lasers, in particular to a wide-tuning laser based on a saturable absorber.
Background
The fiber laser has the advantages of miniaturization, high efficiency, strong environmental adaptability, convenient industrialization and the like, and has very wide application in a plurality of fields such as industry, business, scientific research, military and the like. At present, the main mode for realizing the ultrashort pulse is based on the passive mode locking technology of a semiconductor saturation absorption mirror (SESAM), but the SESAM has high manufacturing cost and is inconvenient to use in optical fibers.
The spectral bandwidth tunability of the filter is based on birefringence compensation in the polarization maintaining fiber. This unique filter allows mode-locked operation of the fiber oscillator and enables the generation of unique laser modes with different output spectral shapes and pulse evolution. The state of a mode-locked all-normal-dispersion (ANDi) laser is determined by three main parameters, namely the Nonlinear (NL) phase shift of the spectral filter, the Group Velocity Dispersion (GVD) and the Bandwidth (BW). Even though the bandwidth of the spectral filter can significantly change the laser output, it is not easy to tune the filter bandwidth. The laser designed by the optical fiber-based spectral filter has better performance, can generate nJ pulse, and has the pulse duration from ps to fs. Although the relevant fiber optic spectral filters have been well explored, these filters have no tunable bandwidth.
Disclosure of Invention
The invention aims to provide a wide-tuning laser based on a saturable absorber, which can adjust the spectral bandwidth.
In order to achieve the above object, the solution of the present invention is:
a broad tuning laser based on a saturable absorber, comprising
The optical fiber device comprises a pumping source, a wavelength division multiplexer, a gain optical fiber, a saturable absorber, a polarization-related isolator, an optical fiber spectrum filter, an optical coupler and a second polarization controller, wherein the wavelength division multiplexer, the gain optical fiber, the saturable absorber and the optical fiber spectrum filter form an annular cavity optical path;
the optical fiber spectrum filter comprises a first polarizer, a second polarizer, a standard single-mode optical fiber, a first polarization controller, a first polarization maintaining optical fiber and a second polarization maintaining optical fiber, wherein the first polarization controller is arranged on the standard single-mode optical fiber between the first polarization maintaining optical fiber and the second polarization maintaining optical fiber.
Further, the pump laser output by the pump source is connected to the first incident end of the wavelength division multiplexer, the emergent end of the wavelength division multiplexer is connected to the saturable absorber through a gain optical fiber, the emergent end of the saturable absorber is connected to the polarization-dependent isolator, the emergent end of the polarization-dependent isolator is connected to the optical fiber spectral filter, the optical coupler is connected with the optical fiber spectral filter and then is connected with a second polarization controller, and the second polarization controller is connected to the second incident end of the wavelength division multiplexer.
Further, the optical fiber coupling-out wavelength of the pump source is 976nm.
Further, the gain fiber is a rare earth doped fiber.
Further, the saturable absorber is prepared by adopting a method of mechanical separation, chemical stripping or vapor deposition.
Further, the lengths of the first polarization maintaining optical fiber and the second polarization maintaining optical fiber are 14-20cm.
Further, the first polarization maintaining optical fiber and the second polarization maintaining optical fiber are spliced to the first polarization controller at an angle of 45 degrees.
Further, the tapping port of the output end of the optical coupler is 80/20.
By adopting the scheme, the invention utilizes the design of the filter based on the optical fiber, can realize the adjustable spectral bandwidth under the principle of birefringence compensation in the polarization maintaining optical fiber, and the unique filter allows the mode locking operation of the optical fiber oscillator and can generate unique laser modes with different output spectral shapes and pulse evolution.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view of an optical path structure according to a preferred embodiment of the present invention;
fig. 2 is a schematic diagram of a fiber spectral filter according to a preferred embodiment of the present invention.
Reference numerals illustrate: 1. a pump source; 2. a wavelength division multiplexer; 3. a saturable absorber; 4. a polarization dependent isolator; 5. an optical coupler; 61. a first polarizer; 62. a second polarizer; 63. a first polarization controller; 64. a first polarization maintaining fiber; 65. a second polarization maintaining fiber; 7. a second polarization controller; 8. a gain fiber; 9. a standard single mode optical fiber; a. an output port.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below.
As shown in fig. 1 and 2, the invention discloses a wide tuning laser based on a saturable absorber 3, which comprises a pump source 1, a wavelength division multiplexer 2, a gain optical fiber 8, the saturable absorber 3, a polarization dependent isolator 4, an optical fiber spectral filter, an optical coupler 5 and a second polarization controller 7, wherein the wavelength division multiplexer 2, the gain optical fiber 8, the saturable absorber 3 and the optical fiber spectral filter form an annular cavity optical path.
The optical fiber spectrum filter is used for carrying out bandwidth tuning, and the wavelength of laser is changed by changing the wavelength corresponding to the low-loss region of the resonant cavity. Specifically, the optical fiber spectral filter includes a first polarizer 61, a second polarizer 62, a standard single-mode optical fiber 9, a first polarization controller 63, a first polarization maintaining optical fiber 64, and a second polarization maintaining optical fiber 65, the first polarization controller 63 being disposed on the standard single-mode optical fiber 9 between the first polarization maintaining optical fiber 64 and the second polarization maintaining optical fiber 65.
The pump laser output by the pump source 1 is connected to a first incident end of the wavelength division multiplexer 2, an emergent end of the wavelength division multiplexer 2 is connected to the saturable absorber 3 through a gain optical fiber 8, the emergent end of the saturable absorber 3 is connected to the polarization dependent isolator 4, the emergent end of the polarization dependent isolator 4 is connected to an optical fiber spectral filter, the optical coupler 5 is connected with the optical fiber spectral filter and then is connected with a second polarization controller 7, and the second polarization controller 7 is connected to a second incident end of the wavelength division multiplexer 2.
The first polarization controller 63 is applied to the standard single mode fiber 9 between the first polarization maintaining fiber 64 and the second polarization maintaining fiber 65, and the first polarization controller 63 is adjusted to create stress-induced birefringence in the standard single mode fiber 9. The first polarization controller 63 applies a linear polarization to the input light, which then propagates along the first polarization maintaining fiber 64, the standard single mode fiber 9, and the second polarization maintaining fiber 65, thereby accumulating a relative phase shift in each fiber according to birefringence, which is wavelength dependent and causes rotation of the polarization state. The length of the first polarization maintaining fiber 64, the second polarization maintaining fiber 65, and the standard single mode fiber 9 between the first polarization maintaining fiber 64 and the second polarization maintaining fiber 65 in this embodiment is between 14 cm and 20cm.
The present embodiment uses the saturable absorber 3 for mode locking, and the output pulse width of the laser is related to the modulation depth of the saturable absorber 3. As the modulation depth of the saturable absorber 3 is increased, the output pulse of the laser can be narrowed, compared with the prior all-fiber structure laser with the saturable absorber for realizing mode locking, the wide-tuning laser based on the saturable absorber 3 has the advantages of obviously narrowing the pulse width, obviously increasing the output power, obviously improving the repetition frequency and obviously reducing the mode locking threshold. Specifically, the saturable absorber 3 can be obtained by mechanical separation, chemical stripping, vapor deposition, or the like.
The present embodiment converts the rotation induced by the first polarization controller 63 in relation to wavelength into amplitude modulation by the second polarization controller 7, resulting in a sinusoidal transmission curve, so that the total birefringence and the bandwidth of the filter can be significantly adjusted by adjusting the stress birefringence in the standard single mode fiber 9.
The pump source 1 is used for outputting pump laser, the wavelength division multiplexer 2 is used for coupling light into an annular cavity optical path, the saturable absorber 3 is used as an optical modulation device for starting a mode locking process, and the optical coupler 5 is used for monitoring the frequency spectrum after the optical fiber spectral filter.
The polarization dependent isolator 4 can provide the same peak isolation effect at any position, and is provided with a Faraday rotor, and the polarization direction of the light wave with the designed wavelength can be rotated by 45 degrees after being adjusted before leaving the factory. The light propagating backward in the polarization dependent isolator 4 has a polarization direction of 45 deg. due to the output polarizer, which is 90 deg. different from the polarization direction of the light on the transmission axis of the input polarizer. Thus, one polarization dependent isolator 4 can block the backward propagating light.
In this embodiment, pump laser with a wavelength of 976nm emitted from the pump source 1 is coupled by the wavelength division multiplexer 2 and then is incident on the gain fiber 8, the pump laser is injected into a standard single mode fiber 9 with a wavelength of about 1m after passing through the gain fiber 8 with a wavelength of 55cm, then the gain laser is injected into the saturable absorber 3 to start the mode locking process, and the polarization dependent isolator 4 ensures that the laser travels unidirectionally to reach the fiber spectral filter and finally is incident on the optical coupler 5 with a wavelength of 80/20. The mode-locked laser pulse with high beam quality is output after passing through the optical coupler 5, and the frequency spectrum after the filter can be monitored at the output port a.
The gain fiber 8 adopts rare earth ion doped fiber, such as erbium doped fiber, ytterbium doped fiber, etc. The first polarization maintaining fiber 64 and the second polarization maintaining fiber 65 are spliced to the first polarization controller 63 at an angle of 45 °.
The laser provided in this embodiment operates the entity below the lasing threshold with very low pump power, verifies the transmission characteristics of the spectrum filter through experiments, observes the output of the filter through 20% output port a of the optical coupler 5, adjusts the first polarization controller 63, and monitors the bandwidth of the analog transmission spectrum output by the optical fiber spectrum filter.
The laser obtains a fiber spectral filter with a bandwidth of 10.8nm by operating the cavity below the lasing threshold to adjust the first polarization controller 63. Then, the pump power is increased and mode locking is achieved by rotating the intracavity waveplate and tuning the second polarization controller 7 with a pump power of 350 mw. The spectral filter characteristics depend on the PM-SMF-PM interface and not the entire fiber cavity, which helps reduce drift in the filter transmission curve compared to existing filters.
The tunability of the bandwidth of the filter is based on the birefringence compensation in the optical fiber spectrum filter, and only the polarization controller is required to be tuned, so that the filter is not required to be rebuilt; and by means of a spectral filter based on birefringence, also high-energy ultrashort pulses can be generated. Therefore, the invention has the advantages of good practicability and operability, compact and small structure, unidirectional laser output, high repetition frequency, high stability and the like, can be widely applied to the fields of national defense, industry, medical treatment and scientific research, and has good application prospect and commercial value.
The principles and embodiments of the present invention have been described in this specification with reference to specific examples, the description of which is only for the purpose of aiding in understanding the method of the present invention and its core ideas; also, it is within the scope of the present invention to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the invention.
Claims (8)
1. A broad tuning laser based on a saturable absorber, characterized by: comprising
The device comprises a pumping source (1), a wavelength division multiplexer (2), a gain optical fiber (8), a saturable absorber (3), a polarization-dependent isolator (4), an optical fiber spectrum filter, an optical coupler (5) and a second polarization controller (7), wherein the wavelength division multiplexer (2), the gain optical fiber (8), the saturable absorber (3) and the optical fiber spectrum filter form an annular cavity optical path;
the optical fiber spectrum filter comprises a first polarizer (61), a second polarizer (62), a standard single-mode optical fiber (9), a first polarization controller (63), a first polarization maintaining optical fiber (64) and a second polarization maintaining optical fiber (65), wherein the first polarization controller (63) is arranged on the standard single-mode optical fiber (9) between the first polarization maintaining optical fiber (64) and the second polarization maintaining optical fiber (65).
2. The saturable absorber-based wide tuning laser of claim 1, wherein: the pump laser output by the pump source (1) is connected to a first incident end of the wavelength division multiplexer (2), an emergent end of the wavelength division multiplexer (2) is connected to the saturable absorber (3) through a gain optical fiber (8), the emergent end of the saturable absorber (3) is connected to the polarization dependent isolator (4), the emergent end of the polarization dependent isolator (4) is connected to the optical fiber spectral filter, the optical coupler (5) is connected with the optical fiber spectral filter and then is connected with a second polarization controller (7), and the second polarization controller (7) is connected to a second incident end of the wavelength division multiplexer (2).
3. The saturable absorber-based wide tuning laser of claim 1, wherein: the optical fiber coupling output wavelength of the pump source (1) is 976nm.
4. The saturable absorber-based wide tuning laser of claim 1, wherein: the gain fiber (8) is a rare earth doped fiber.
5. The saturable absorber-based wide tuning laser of claim 1, wherein: the saturable absorber (3) is prepared by adopting a method of mechanical separation, chemical stripping or vapor deposition.
6. The saturable absorber-based wide tuning laser of claim 1, wherein: the lengths of the first polarization maintaining optical fiber (64) and the second polarization maintaining optical fiber (65) are 14-20cm.
7. The saturable absorber-based wide tuning laser of claim 1, wherein: the first polarization maintaining optical fiber (64) and the second polarization maintaining optical fiber (65) are spliced to the first polarization controller (63) at an angle of 45 degrees.
8. The saturable absorber-based wide tuning laser of claim 1, wherein: the tapping port of the output end of the optical coupler (5) is 80/20.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311489468.7A CN117613655A (en) | 2023-11-09 | 2023-11-09 | Wide tuning laser based on saturable absorber |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311489468.7A CN117613655A (en) | 2023-11-09 | 2023-11-09 | Wide tuning laser based on saturable absorber |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117613655A true CN117613655A (en) | 2024-02-27 |
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| CN202311489468.7A Pending CN117613655A (en) | 2023-11-09 | 2023-11-09 | Wide tuning laser based on saturable absorber |
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| Country | Link |
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| CN (1) | CN117613655A (en) |
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2023
- 2023-11-09 CN CN202311489468.7A patent/CN117613655A/en active Pending
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