CN107768973A - It is a kind of can precision tuning Brillouin's multi-wavelength optical fiber laser - Google Patents

Abstract

The invention discloses it is a kind of can precision tuning Brillouin's multi-wavelength optical fiber laser, ring resonator is connected between laser pumping source A and multi-wavelength generation cavity, the annular resonance intracavitary is provided with the vertical wave filter difficult to understand for tuning laser wavelength, and the MOPA structure for amplifying of increase input optical power is provided with the multi-wavelength generation cavity；MOPA structure for amplifying provides gain for highly nonlinear optical fiber, and the laser of the laser for inputting highly nonlinear optical fiber and highly nonlinear optical fiber output is amplified, and makes to excite the stokes light for producing more stages in highly nonlinear optical fiber, so as to export more wavelength.The laser of input is tuned by founding wave filter difficult to understand, it is possible to achieve precision tuning is carried out by temperature in tens nanometer ranges.

Description

A Precisely Tunable Brillouin Multiwavelength Fiber Laser

technical field

The invention relates to the field of lasers, in particular to a precisely tunable Brillouin multi-wavelength fiber laser.

Background technique

A multi-wavelength fiber laser (MWFL) is a fiber laser that can simultaneously generate several, dozens or even hundreds of laser wavelengths in the spectral range of tens of nanometers. In recent years, with the continuous development of optical technology, people have begun to notice the great potential of 2μm mid-infrared multi-wavelength fiber lasers in the fields of equipment testing, optical fiber sensor networks, optical microwave generation, and wavelength division multiplexing optical communications. has become one of the research hotspots.

At present, the means to achieve multi-wavelength lasers in the 2μm band can be mainly divided into two categories. The first category is to use the combination of doped fiber lasers and comb filters to generate multi-wavelengths. Common comb filters such as Mach-Zehnder and lyot filter, Special fiber gratings, etc., have a simple principle and direct thinking. The other is to use nonlinear effects to achieve multiple wavelengths, such as four-wave mixing, stimulated Raman scattering, stimulated Brillouin scattering, etc., all of which have the ability to generate new wavelengths. However, compared with the first type, the multi-wavelength generated by the nonlinear effect is determined by the physical characteristics and does not need to be adjusted, so the device structure is simpler and the intracavity loss is lower.

At present, there are few researches at home and abroad on applying the stimulated Brillouin scattering effect to the 2μm band to generate multi-wavelength lasers. In 2013, Wang et al. of the National University of Defense Technology reported a multi-wavelength Brillouin laser based on quartz single-mode fiber, using a 450m single-mode fiber as the Brillouin gain medium, and finally realized multi-wavelength laser with 5 wavelengths spectral line. Subsequently, in 2014, Hu et al. from Zhejiang University proposed for the first time a wavelength-switchable multi-wavelength mixed-gain Brillouin thulium-doped fiber laser. By simply adjusting the state of the components in the laser structure, the wavelength interval of the output multi-wavelength laser can be switched between a single Brillouin frequency shift and a double Brillouin frequency shift, and the corresponding frequency shifts are 7.62GHz ( 0.1nm) and 15.24GHz (0.2nm). For these two output modes, 7 and 11 multi-wavelength lasers are obtained respectively within a bandwidth of 20dB. It can be seen from this that the laser that can generate multi-wavelength laser in the 2 μm band has the problems that the output wavelength cannot be tuned accurately in a wide range and the number of multi-wavelengths is small.

Contents of the invention

The purpose of the present invention is to provide a precisely tunable Brillouin multi-wavelength fiber laser, which solves the problem that current lasers that can generate multi-wavelength lasers in the 2 μm band cannot accurately tune output wavelengths in a large range and the number of multi-wavelengths is small. question.

The technical scheme that the present invention adopts is as follows:

A precisely tunable Brillouin multi-wavelength fiber laser, comprising a laser pumping source A, the laser pumping source A is connected to a multi-wavelength generating cavity, and the laser pumping source A is connected to a multi-wavelength generating cavity A ring resonant cavity, the ring resonant cavity is provided with a Leo filter for tuning the laser wavelength, and the multi-wavelength generating cavity is provided with an MOPA amplification structure for increasing input optical power.

Further, the ring resonator includes a pumping beam combiner A connected to the laser pumping source A, and the pumping beam combiner A is sequentially connected to a double-clad thulium-doped fiber A, a coupler A, and a Leo filter device, isolator, and polarization controller A, and the polarization controller A is connected to the pump beam combiner A.

Further, the Leo filter includes a tilted fiber Bragg grating A connected to two ends of the coupler A, the tilted fiber Bragg grating A is connected to a polarization maintaining fiber and a tilted fiber Bragg grating B in turn, and the tilted fiber Bragg grating B is connected to the Isolator.

Further, the multi-wavelength generating cavity includes a coupler B, one end of the coupler B is connected to two ends of the coupler A, and the two ends of the coupler B are respectively connected to a spectrometer and a polarization controller B, The polarization controller B is connected to the 1 end of the circulator A, the 2 ends of the circulator A are connected to the 1 end of the coupler B, the 3 ends of the circulator A are connected to the MOPA amplifying structure, and the MOPA amplifying structure A highly nonlinear optical fiber is arranged inside, and the MOPA amplifying structure is connected to the circulator B.

Further, the MOPA amplification structure includes a laser pumping source B, the laser pumping source B is connected to end 1 of the pumping beam combiner B, and end 1 of the pumping beam combiner B is connected to the end of the circulator A 3 ends, the 2 ends of the pump beam combiner B are connected to the double-clad thulium-doped fiber B, the high nonlinear fiber, and the double-clad thulium-doped fiber C in sequence, and the double-clad thulium-doped fiber C is connected to the pumping The 2 ends of the beam combiner C, the 1 end of the pumping beam combiner C are respectively connected to the laser pump source C and the circulator B.

In summary, owing to adopting above-mentioned technical scheme, the beneficial effect of the present invention is:

1. The MOPA amplification structure provides gain for the highly nonlinear fiber, and amplifies both the laser input into the highly nonlinear fiber and the laser output from the highly nonlinear fiber, so that more orders of Stokes light can be excited in the highly nonlinear fiber , thus outputting more wavelengths.

2. The input laser is tuned through the Leo filter, which can realize precise tuning by temperature in the range of tens of nanometers.

Description of drawings

The invention will be illustrated by way of example with reference to the accompanying drawings, in which:

Fig. 1 is the overall structure diagram of the present invention.

Reference signs: 1-laser pumping source A, 2-ring resonator, 201-pumping beam combiner A, 202-double-clad thulium-doped fiber A, 203-coupler A, 204-isolator, 205- Polarization controller A, 206-tilted fiber grating A, 207-polarization maintaining fiber, 208-tilted fiber grating B, 3-multi-wavelength generation cavity, 301-coupler B, 302-polarization controller B, 303-circulator A , 304-high nonlinear fiber, 305-circulator B, 306-laser pump source B, 307-pump combiner B, 308-double-clad thulium-doped fiber B, 309-double-clad thulium-doped fiber C , 310-pump beam combiner C, 311-laser pump source C, 4-spectrometer.

Detailed ways

All features disclosed in this specification, or steps in all methods or processes disclosed, may be combined in any manner, except for mutually exclusive features and/or steps.

The present invention will be described in detail below in conjunction with FIG. 1 .

A precisely tunable Brillouin multi-wavelength fiber laser, including a 793nm laser pumping source A1, the 793nm laser pumping source A1 is connected to a ring resonant cavity 2, and the ring resonant cavity 2 is provided with a device for tuning the laser wavelength In the Leo filter, the ring resonant cavity 2 is connected to a multi-wavelength generating cavity 3, and a MOPA amplification structure for increasing input optical power is arranged in the multi-wavelength generating cavity 3.

The specific structure is as follows:

The 793nm laser pumping source A1 is connected to the pumping beam combiner A201, and the pumping beam combiner A201 is connected to the double-clad thulium-doped fiber A202, the coupler A203, the 45° inclined fiber grating A206, the polarization maintaining fiber 207, A 45° inclined fiber grating B208, an isolator 204, and a polarization controller A205, the polarization controller A205 is connected to the pump beam combiner A201.

Two ends of the coupler A203 of the ring resonator 2 are connected to one end of the coupler B301, and two ends of the coupler B301 are respectively connected to a spectrometer 4 and a polarization controller B302, and the polarization controller B302 is connected to the circulator A303 Terminal 1 of the circulator A303 is connected to terminal 1 of the coupler B301, terminal 3 of the circulator A303 is connected to terminal 1 of the pumping beam combiner B307, and terminal 1 of the pumping beam combiner B307 Also connect the 793nm laser pumping source B306, the 2 ends of the pump beam combiner B307 are connected to the double-clad thulium-doped fiber B308, the high nonlinear fiber 304, the double-clad thulium-doped fiber C309 in turn, and the double-clad doped The thulium fiber C309 is connected to two ends of the pumping beam combiner C310, and the first end of the pumping beam combiner C310 is respectively connected to the 793nm laser pumping source C311 and the circulator B305.

The working principle of the present invention is as follows:

The 793nm laser pump source generates continuous pump light with a wavelength of 793nm, and the pump beam combiner A201 couples the pump light and the laser light that has been transmitted in the ring resonator 2 for one week to the double-clad thulium-doped fiber A202, The cladding thulium-doped fiber A202 is used as a gain fiber to provide an energy level structure for generating 2.0μm band lasers. The rare earth ions in the cladding thulium-doped fiber A202 absorb 793nm pump light and then generate 2.0μm band lasers through energy level transitions; The 2.0 μm band laser is input into the Leo filter, and changing the temperature of its polarization-maintaining fiber 207 can cause its transmission wavelength to be tunable; the isolator 204 is used to ensure the unidirectional transmission of the laser in the cavity, and the polarization controller A205 changes and controls The polarization state of the laser, the coupler A203 divides the 2.0μm band laser into two parts, one part is output to the multi-wavelength generation cavity 3 through the 2-terminal, and the other part continues to transmit in the ring resonator 2;

The 793nm laser generated by the 793nm laser pump source B306 is coupled into the double-clad thulium-doped fiber B308 by the pump beam combiner B307; the 793nm laser generated by the 793nm laser pump source C311 is coupled by the pump beam combiner C310 Enter the double-clad thulium-doped fiber C309; form the MOPA amplification structure, and carry out MOPA amplification at the two ends of the high nonlinear fiber 304, so that the power of the laser light is high enough when passing through the high nonlinear fiber 304, and the high nonlinear fiber 304 is used as The Brillouin gain medium produces Brillouin nonlinear gain, and the highly nonlinear fiber 304 can generate higher-power first-order Stokes light, and the condition for generating second-order Stokes light is to reach a certain threshold. That is, the optical power of the first-order Stokes is large enough to excite the second-order Stokes light. At this time, the first-order Stokes light is equivalent to the original Brillouin pump light, and the second-order Stokes light The role of Stokes light is equivalent to the original first-level Stokes light. Under sufficiently strong pumping power, such a process can occur repeatedly in the highly nonlinear optical fiber 304, which can produce more wavelength output; the multi-wavelength laser generated returns to the coupler B301 through the circulator A303, and passes through The coupler B301 splits the output, and finally observes the output of the multi-wavelength spectral lines on the spectrometer 4 .

Claims (5)

1. it is a kind of can precision tuning Brillouin's multi-wavelength optical fiber laser, including laser pumping source A (1), the laser pump (ing) Source A (1) connection multi-wavelength generation cavities (3), it is characterised in that：Between the laser pumping source A (1) and multi-wavelength generation cavity (3) also Ring resonator (2) is connected with, the vertical wave filter difficult to understand for tuning laser wavelength, institute are provided with the ring resonator (2) State the MOPA structure for amplifying that increase input optical power is provided with multi-wavelength generation cavity (3).

2. it is according to claim 1 it is a kind of can precision tuning Brillouin's multi-wavelength optical fiber laser, it is characterised in that：Institute State pump combiner A (201), the pump combiner A that ring resonator (2) includes connecting the laser pumping source A (1) (201) double clad thulium doped fiber A (202), coupler A (203), vertical wave filter difficult to understand, isolator (204), polarization control are sequentially connected Device A (205) processed, the Polarization Controller A (205) connect the pump combiner A (201).

3. it is according to claim 2 it is a kind of can precision tuning Brillouin's multi-wavelength optical fiber laser, it is characterised in that：Institute State inclined optical fiber grating A (206), the inclined optical fiber grating A that vertical wave filter difficult to understand includes connecting the ends of coupler A (203) 2 (206) polarization maintaining optical fibre (207) and inclined optical fiber grating B (208) are sequentially connected, described in inclined optical fiber grating B (208) connection Isolator (204).

4. it is according to claim 3 it is a kind of can precision tuning Brillouin's multi-wavelength optical fiber laser, it is characterised in that：Institute Stating multi-wavelength generation cavity (3) includes coupler B (301), and 1 end of the coupler B (301) connects the coupler A (203) 2 ends, 2 ends of the coupler B (301) are connected to spectrometer (4) and Polarization Controller B (302), the Polarization Controller B (302) connection circulator A (303) 1 end, 2 ends of the circulator A (303) connect 1 end of the coupler B (301), institute Circulator A (303) 3 ends connection MOPA structure for amplifying is stated, highly nonlinear optical fiber is provided with the MOPA structure for amplifying (304), the MOPA structure for amplifying connection circulator B (305).

5. it is according to claim 4 it is a kind of can precision tuning Brillouin's multi-wavelength optical fiber laser, it is characterised in that：Institute Stating MOPA structure for amplifying includes laser pumping source B (306), laser pumping source B (306) the connection pump combiner B (307) 1 end, pump combiner B (307) 1 end are connected to 3 ends of the circulator A (303), and the 2 of the pump combiner B (307) End is sequentially connected double clad thulium doped fiber B (308), highly nonlinear optical fiber (304), double clad thulium doped fiber C (309), described double Covering thulium doped fiber C (309) connection pump combiner C (310) 2 ends, 1 end of the pump combiner C (310) connect respectively Laser pumping source C (311) and the circulator B (305).