CN202333431U

CN202333431U - 22GHz-gap multi-wavelength Brillouin circular cavity optical fiber laser

Info

Publication number: CN202333431U
Application number: CN2011204860776U
Authority: CN
Inventors: 龚华平; 李小瑞; 屠于梦; 金永兴; 王剑锋
Original assignee: China Jiliang University
Current assignee: China Jiliang University
Priority date: 2011-11-29
Filing date: 2011-11-29
Publication date: 2012-07-11
Anticipated expiration: 2021-11-29

Abstract

The utility model discloses a 22GHz-gap multi-wavelength Brillouin annular cavity optical fiber laser, which comprises a circular cavity structure formed by a first optical fiber circulator 4, a first optical coupler 5, a single mode fiber 6, a second optical fiber circulator 7, a polarization controller 8, a second optical isolator 9, an erbium-doped optical fiber amplifier (EDFA) 10 and a second optical coupler 11, a distributed feed back (DFB) laser 1, a tunable optical attenuator 2 and a first optical isolator 3, wherein one input end of the first optical coupler is connected with a third port of the second optical fiber circulator to form a reversed S-shaped structure to achieve the Brillouin cascade effect. First-stage Strokes light signals transmitted in a cavity anticlockwise pass through the second optical fiber circulator 7 and enter the single mode fiber to generate second-stage back scattered Strokes light signals which pass through the second optical fiber circulator and the first optical coupler and then enter the single mode fiber clockwise to generate third-stage Strokes light signals which are transmitted anticlockwise, the third-stage Strokes light signals are amplified through gain media provided with the EDFA, one portion of the third-stage Strokes light signals is directly output through the second optical coupler, and the other portion of the third-stage Strokes light signals enters again a circulation light path, so that the device can only output odd-stage Strokes light to obtain multi-wavelength laser output with wavelength gap as 22 GHz. The 22GHz-gap multi-wavelength Brillouin annular cavity optical fiber laser is simple in structure and stable in wavelength gap.

Description

A kind of 22GHz is the multi-wavelength Brillouin circular cavity optic fibre laser at interval

Technical field

The utility model relates to fiber laser, specifically is a kind of 22GHz multi-wavelength Brillouin circular cavity optic fibre laser at interval.

Background technology

The multiwavelength laser source is in light sensing, spectroscopic optics, microwave photon signal processing, and aspect such as high power capacity wavelength division multiplexing communications systems all has very, and important use is worth.Fiber laser comprises big gain, high saturation energy and relatively low noise coefficient demonstrating its exclusive advantage aspect the generation multi-wavelength.Yet; Because the competition of the strong mode in the HOMOGENEOUS BROADENING MEDIUM Er-doped fiber; Suppressed to stablize in the erbium doped fiber laser under the normal temperature generation of multiwavelength laser, in order to produce multi-wavelength optical fiber laser at normal temperatures, the method for head it off comprises Er-doped fiber is immersed in the liquid nitrogen; Adopt the laser cavity of inserting frequency shifter; In overlapping fiber laser cavity, use polarisation hole-burning effect, in nonlinear fiber loop, adopt four wave mixing, in laser, make brillouin gain and Er-doped fiber gain way of combining etc.

Wherein, Multi-wavelength Brillouin erbium-doped fiber laser is a kind of multiple-wavelength laser based on stimulated Brillouin scattering (SBS); Can produce the effective way of larger amt optical maser wavelength, its wavelength interval is determined by the optical fiber Brillouin frequency displacement, compares with other multiple-wavelength laser; It has that the wavelength interval is stable, width and characteristics such as simple in structure, at aspects such as Fibre Optical Sensor and close wavelength-division multiplex technologies very application prospects is arranged.Gain is comprehensive by stimulated Brillouin scattering non-linear gain in the linear gain of Er-doped fiber and the optical fiber; Utilize the stimulated Brillouin scattering non-linear gain that hangs down threshold value can suppress the HOMOGENEOUS BROADENING mechanism of Er-doped fiber effectively; Through multistage Brillouin scattering cascade, can realize natural wavelength Brillouin's multiwavelength laser output at interval.The structure of common Brillouin erbium-doped fiber laser mainly contains two types: linear cavity and ring cavity structure, linear cavity need high reflectance chamber mirror or fiber optic loop to realize feedback, and complex structure and stability are not high; Brillouin fiber ring laser is the extremely narrow high-coherence light source of a kind of live width, has advantages such as frequency stabilization, gain direction property sensitivity, in fields such as temperature sensor, narrow-band amplifier, coherent optics communications important application is arranged.

At present, the wavelength interval of multi-wavelength Brillouin circular cavity optic fibre laser generally is about 11GHz, and other wavelength intervals are seldom arranged, and this has seriously restricted the range of application of multi-wavelength optical fiber laser.

Summary of the invention

The utility model proposes a kind of 22GHz multi-wavelength Brillouin circular cavity optic fibre laser at interval; (EDFA) provides linear gain by erbium-doped fiber amplifier; SBS by in the monomode fiber provides non-linear gain; Make Stokes (Stokes) the Brillouin flashlight output of having only odd-order through cascading, realize that the wavelength interval is the multiwavelength laser output of 22GHz.

The utility model comprises ring cavity structure that first optical fiber circulator 4, first optical coupler 5, monomode fiber 6, second optical fiber circulator 7, Polarization Controller 8, second optical isolator 9, EDFA image intensifer 10, second optical coupler 11 constitute and Distributed Feedback Laser 1, variable optical attenuator 2, first optical isolator 3, and wherein " fall S " structure of constituting of first optical coupler and first optical fiber circulator has realized Brillouin's cascading.The light process variable optical attenuator of Distributed Feedback Laser outgoing and first optical isolator are after first optical fiber circulator gets into monomode fiber; Produce stimulated Brillouin scattering light; Light frequency moves down about 11GHz than incident light, and the light signal of first Stokes dorsad that scattering is returned amplifies through EDFA, directly exports through a part of light behind second optical coupler; Another part light signal is through second optical isolator and Polarization Controller; Get into monomode fiber counterclockwise through second optical fiber circulator and produce Brillouin scattering dorsad, the scattered light signal frequency displacement moves down about 11GHz once more, and clockwise Second-order Stokes light signal gets into three counterclockwise rank Stokes light of monomode fiber generation once more through second optical circulator and first optical coupler; The Stokes light signal amplifies a back part through EDFA and directly exports through optical coupler; Another part gets into the light path circulation, repeats said process, can be at the Stokes flashlight of odd-order such as second optical coupler output one, three, five; In spectrometer, can observe wavelength is the multiwavelength laser output of 22GHz, thereby has realized being spaced apart the multi-wavelength Brillouin circular cavity optic fibre laser of 22GHz.

Wherein, " S " structure is made up of first optical coupler and second optical fiber circulator; Input of first optical coupler and the 3rd port of second optical fiber circulator link to each other; A part of Stokes flashlight in order to will in the chamber, circulating counterclockwise gets in the monomode fiber along clockwise again, and single order is exported thereby produce multiwavelength laser along the Stokes flashlight of counterclockwise transmission under producing.

Acting as light circularly from first port transmission of described optical fiber circulator to second port, with optical transmission to the three ports of second port.

The centre wavelength of said Distributed Feedback Laser 1 is the C-band light source of 1550nm, and live width is less than 1MHz.

The about 100mW of saturated Output optical power of described EDFA image intensifer 10, be used for light in the compensated fiber loss and amplify the light signal in the loop.

The coupling ratio of said first optical coupler 5 is 60: 40, and 60% coupling ratio output port connects the 3rd port of second optical fiber circulator 7.

The coupling ratio of said second optical coupler 11 is 90: 10, and 10% coupling ratio output port is used for light output.

Described monomode fiber 6 length are 1 to 10km.

The above all connection medium is standard single-mode fiber.

The utility model is mainly used in as optical communication, light sensing; Light source in the wavelength division multiplexing; Adopted that Brillouin's non-linear gain combines in linear gain and the monomode fiber of erbium-doped fiber amplifier, can access stable multi-wavelength output at normal temperatures, and the optical maser wavelength of output has been stable at interval.

Description of drawings

Fig. 1 is the structural representation of the utility model;

Fig. 2 is 60: 40 for the utility model at the first optical coupler coupling ratio, and the second optical coupler coupling ratio is the laser output spectrum figure that records with spectrometer under 90: 10 the situation.

In the drawings:

1, Distributed Feedback Laser; 2, variable optical attenuator; 3, first optical isolator; 4, first optical fiber circulator; 5, first optical coupler; 6, monomode fiber; 7, second optical fiber circulator; 8, Polarization Controller; 9, second optical isolator; 10, EDFA image intensifer; 11, second optical coupler

Embodiment

Below in conjunction with accompanying drawing and embodiment the utility model is described further.

As shown in Figure 1; The utility model is achieved in that its characterization step is: from light source Distributed Feedback Laser 1 send narrow-linewidth laser through tunable attenuator 2 and first optical isolator 3 as Brillouin's pumping source, then through first optical circulator 4 and first optical coupler 5 clockwise in the entering monomode fibers 6; In monomode fiber, produce stimulated Brillouin scattering and form the counterclockwise flashlight of Stokes dorsad; About the approximately little 11GHz of its flashlight frequency ratio incident light, behind optical fiber circulator, amplify Brillouin Stokes signal by EDFA image intensifer 10 again, a part of light signal is directly exported through second optical coupler 11; Another part signal through second optical coupler after second optical isolator 9, Polarization Controller 8 and second optical fiber circulator 7 get into monomode fibers; Produce Brillouin scattering dorsad, i.e. a clockwise Second-order Stokes flashlight, the Second-order Stokes flashlight gets into second optical fiber circulator and first optical coupler 5 gets in the monomode fiber again clockwise; Because Brillouin scattering produces three counterclockwise rank Stokes flashlights dorsad; Amplify by EDFA through first optical fiber circulator then, in the output of second fiber coupler, this process above repeating; Can be at the Stokes flashlight of odd-order such as second optical coupler output one, three, five, in spectrometer, can observe wavelength is the multiwavelength laser output of 22GHz.Tunable attenuator 2 act as the change pumping light power; The flashlight that makes in the annular chamber that act as of second optical isolator 9 only transmits along counterclockwise.

Claims

1. 22GHz multi-wavelength Brillouin circular cavity optic fibre laser at interval; It is characterized in that comprising Distributed Feedback Laser (1), variable optical attenuator (2), first optical isolator (3) and the annular chamber that constitutes by first optical fiber circulator (4), first optical coupler (5), monomode fiber (6), second optical fiber circulator (7), Polarization Controller (8), second optical isolator (9), EDFA image intensifer (10), second optical coupler (11); Distributed Feedback Laser (1) links to each other with the input of variable optical attenuator (2); The output of optical attenuator links to each other with first optical isolator (3) input; First port (4-1) of the output of first optical isolator and first optical fiber circulator links to each other; Second port (4-2) of first optical fiber circulator links to each other with an input of first optical coupler (5); The 3rd port (4-3) of first optical fiber circulator links to each other with the input of image intensifer EDFA (11); The output of first optical coupler links to each other with an end of monomode fiber (6), and second port (7-2) of the other end of monomode fiber and second optical fiber circulator links to each other, and another input of optical fiber circulator the 3rd port (7-3) and first optical coupler links to each other; First port (7-1) of second optical fiber circulator links to each other with the input of Polarization Controller (8); The output of Polarization Controller links to each other with second optical isolator (9) output, and an output of the input of second optical isolator and the 3rd optical coupler (11) links to each other, and the input of the 3rd fiber coupler links to each other with the output of EDFA; Another output of the 3rd optical coupler is the output port of whole device, links to each other with spectrometer.

2. a kind of 22GHz according to claim 1 is the multi-wavelength Brillouin circular cavity optic fibre laser at interval; It is characterized in that; Said first optical coupler 5 and second optical fiber circulator 7 constitute " S " structure; An input by first optical coupler links to each other with second optical fiber circulator the 3rd port, produces Brillouin's cascading.

3. a kind of 22GHz according to claim 1 is the multi-wavelength Brillouin circular cavity optic fibre laser at interval, it is characterized in that the centre wavelength of said Distributed Feedback Laser 1 is the C-band light source of 1550nm, and live width is less than 1MHz.

4. a kind of 22GHz according to claim 1 is the multi-wavelength Brillouin circular cavity optic fibre laser at interval, it is characterized in that the coupling ratio of said first optical coupler 5 is 60: 40, and 60% coupling ratio output port connects the 3rd port of second optical fiber circulator 7.

5. a kind of 22GHz according to claim 1 is the multi-wavelength Brillouin circular cavity optic fibre laser at interval, it is characterized in that the coupling ratio of said second optical coupler 11 is 90: 10, and 10% coupling ratio output port is used for light output.