CN105633788A

CN105633788A - Graphene-based Q-switched pulse fiber narrow line-width laser

Info

Publication number: CN105633788A
Application number: CN201610159097.XA
Authority: CN
Inventors: 庾财斌; 吴宇; 姚佰承; 饶云江
Original assignee: University of Electronic Science and Technology of China
Current assignee: University of Electronic Science and Technology of China
Priority date: 2016-03-21
Filing date: 2016-03-21
Publication date: 2016-06-01

Abstract

The invention relates to the technical fields of optical fiber technology, optical engineering and material engineering, in particular to a graphene-based Q-switched pulse fiber narrow line-width laser. A distributed feedback bragg grating DFB is fabricated on an erbium-doped fiber; the fabricated DFB region completely coats a graphene film; with graphene as a Q-switched material, namely a saturable absorber, of a DFB narrow line-width cavity, rapid adjustment of the loss of the graphene on a DFB composite cavity when the power rate of a pump light is greater than 5MHz is achieved; and high-frequency pulse laser output is generated. The all-fiber pulse narrow line-width laser for carrying out Q-switching on a fiber laser resonant cavity is achieved, has the advantages of being low in cost, simple in structure, good in stability, high in modulation rate, small in output line-width, easy to integrate and the like, and has a wide application prospect in the fields of optical fiber communication and optical fiber sensing.

Description

A kind of pulse mode fibre-optical narrow-line laser apparatus adjusting Q based on Graphene

Technical field

The present invention relates to optical fiber technology, optical engineering and field of material engineering technology, it is specifically related to opticfiber communication, Fibre Optical Sensor and fiber laser technology.

Background technology

Optical fiber laser is as a kind of very important optics, and owing to its volume is little, cost is low, and the plurality of advantages being easy to integrated is widely used in the fields such as industrial processes, medical treatment, communication, sensing. Particularly pulse mode narrow cable and wide optical fiber laser, due to its line width, signal to noise ratio height, efficiency height, the characteristic such as remote controlled so that it is all of great significance in opticfiber communication, the application in the fields such as Fibre Optical Sensor.

In sensing and the communications field, conventional Q-regulating method has and turns mirror and adjust Q, electric-optically Q-switched, acousto-optic Q modulation and saturated absorption to adjust Q etc. In first three methods, the loss of resonator is by external drive source control, is called actively Q-switched. In rear one method, the loss of resonator depends on endovenous laser light intensity, is called passive Q-adjusted. At present, the requirement of Q-switched laser is more and more higher. Traditional Q-switched laser is by material, and the restriction of cost and technical matters, exists modulation module complicated, and modulation rate is slow, exports the defects such as stable not, is unfavorable for integrated and long range propagation.

Traditional Q-switched laser is unfavorable for integrated and long range propagation not enough, becomes some problems meeting practical application request.

Summary of the invention

For above-mentioned existing problems or deficiency, the present invention provides a kind of pulse mode fibre-optical narrow-line laser apparatus adjusting Q based on Graphene, solves tradition Q-switched laser and is unfavorable for integrated and problem that is long range propagation deficiency.

The pulse mode fibre-optical narrow-line laser apparatus of Q should be adjusted based on Graphene, it is characterized in that: on one section of Er-doped fiber, make a distributed feedback bragg grating DFB, and wrap up graphene film completely in obtained DFB region, using Graphene as the Q switched material in DFB narrow linewidth chamber and saturated absorbing body, realize pumping light power speed and it is greater than the rapid adjustment Graphene of 5MHz to the loss of DFB Compound Cavity, produce high-frequency impulse Laser output.

DFB length 2 centimetres, Er-doped fiber diameter 125 microns, the fibre diameter in DFB region is 8 microns, and graphene film is the single-layer graphene of 0.38 nanometer, and graphene film parcel region is DFB region, and length is 2 centimetres.

Its preparation method is specially:

Step 1, on one section of Er-doped fiber, with hydrofluoric acid erosion removal fibre cladding, make a DFB;

Step 2, corrode obtained DFB region in step 1 and wrap up a layer graphene film completely, as saturated absorbing body, carry out Q-switch laser output for the narrow-linewidth laser produced by DFB.

The working process of the present invention is: adjust the pulse mode fibre-optical narrow-line laser apparatus of Q to connect a wave division multiplex coupler by based on Graphene, the continuous pump light of 980 nano wavebands is injected the input terminus of wave division multiplex coupler, this pump light produces the narrow-linewidth laser of 1550 nano wavebands in the laser, it is corroded due to the covering in DFB region and has wrapped up by Graphene so that the evanscent field of 1550 nano wavebands has acted on Graphene. When pumping light power is less, owing to the Graphene saturated absorption characteristic DFB loss of resonator is big, threshold value height, without Laser output. When increase pumping light power, exceeding Graphene saturated absorption threshold value, the loss of the Compound Cavity being made up of Graphene and DFB reduces, and excitation threshold reduces instantaneously, forming centre wavelength is that the narrow-linewidth laser pulse of 1550 nanometers exports, and finally output terminal at wave division multiplex coupler exports.

In the present invention, single-layer graphene serves topmost effect, it is achieved to the tune Q of distributed Feedback bragg grating narrow-linewidth laser. Single-layer graphene is as the maximum two-dimensional film material of a kind of surface area/volume ratio, and it has unique physicochemical property, and wherein saturated absorption is one of its most typical characteristic. When the light wave intensity inputted exceedes threshold value, the absorbent properties of this uniqueness can start to become saturated. This kind of nonlinear optics behavior is called saturable absorption, and threshold value is called saturated fluency. Because the overall light wave of Graphene absorbs and zero energy gap character, Graphene is easy to just become saturated, and then the laser that can realize centre wavelength 1550 nano waveband to DFB generation carries out adjusting Q, produces the output of pulse mode narrow-linewidth laser.

In sum, it is low that the present invention has cost, and structure is simple, good stability, and modulation rate is fast, and output line width, is easy to integrated advantage, is with a wide range of applications in opticfiber communication and sensory field of optic fibre.

Accompanying drawing explanation

Fig. 1 is the three-dimensional structure schematic diagram of the present invention;

Fig. 2 is the implementation system figure of the present invention;

Fig. 3 is the time domain experimental result schematic diagram of the present invention;

Fig. 4 is the narrow-linewidth laser frequency domain figure under different pump power;

Fig. 5 is the narrow linewidth pulse laser time-domain figure under different pump power;

Reference numeral: 1-single-mode fiber, 2-distributed feed-back fiber grating, 3-Graphene, 4-980 nanometer of pumping laser, 5-spectrograph and oscilloscope, 6-wave division multiplex coupler.

Embodiment

Below in conjunction with accompanying drawing and specific embodiment, the invention will be further described:

Shown in composition graphs 1, Fig. 2, making the DFB of 2 centimetres on Er-doped fiber, one end connects wave division multiplex coupler. With the fibre cladding in hydrofluoric acid erosion removal DFB region, and at the DFB region of corrosion parcel Graphene, Graphene thickness is 0.38 nanometer, and packages length is 2 centimetres.

Er-doped fiber diameter 125 microns, the fibre diameter in DFB region is 8 microns, and graphene film is the single-layer graphene of 0.38 nanometer, and graphene film parcel region is DFB region, and length is 2 centimetres.

Fig. 3 is the time domain experimental result schematic diagram of the present invention, shows luminous power distribution trend on a timeline. 980 nanometers of continuous pumping laser fluences enter the input terminus of wave division multiplex coupler, and output terminal connects spectrograph and oscilloscope. 980 nanometers of pump lights, in the DFB of er-doped, produce the laser of 1550 nano wavebands, as shown in Figure 4. It is corroded due to the covering in DFB region and has wrapped up by Graphene, the evanscent field of 1550 nano wavebands is made to act on Graphene, owing to Q characteristic is adjusted in the saturated absorption of Graphene, after 980 pumping light powers are increased to Graphene saturated absorption threshold value, the narrow-linewidth laser that the output terminal at wave division multiplex coupler just can obtain pulse exports. By controlling 980 pumping light powers, the switch that just can realize paired pulses laser exports, as shown in Figure 5.

Claims

1. adjust the pulse mode fibre-optical narrow-line laser apparatus of Q based on Graphene for one kind, it is characterized in that: on one section of Er-doped fiber, make a distributed feedback bragg grating DFB, and wrap up graphene film completely in obtained DFB region, using Graphene as the Q switched material in DFB narrow linewidth chamber and saturated absorbing body, realize pumping light power speed and it is greater than the rapid adjustment Graphene of 5MHz to the loss of DFB Compound Cavity, produce high-frequency impulse Laser output.

2. the pulse mode fibre-optical narrow-line laser apparatus of Q is adjusted as claimed in claim 1 based on Graphene, it is characterized in that: DFB length 2 centimetres, Er-doped fiber diameter 125 microns, the fibre diameter in DFB region is 8 microns, graphene film is the single-layer graphene of 0.38 nanometer, graphene film parcel region is DFB region, and length is 2 centimetres.

3. the preparation method of the pulse mode fibre-optical narrow-line laser apparatus of Q is adjusted as claimed in claim 1 based on Graphene:

4. the working process of the pulse mode fibre-optical narrow-line laser apparatus of Q is adjusted as claimed in claim 1 based on Graphene:

The pulse mode fibre-optical narrow-line laser apparatus of Q is adjusted to connect a wave division multiplex coupler by based on Graphene, the continuous pump light of 980 nano wavebands is injected the input terminus of wave division multiplex coupler, this pump light produces the narrow-linewidth laser of 1550 nano wavebands in the laser, it is corroded due to the covering in DFB region and has wrapped up by Graphene so that the evanscent field of 1550 nano wavebands has acted on Graphene;

When pumping light power is less, owing to the Graphene saturated absorption characteristic DFB loss of resonator is big, threshold value height, without Laser output;

When increase pumping light power, exceeding Graphene saturated absorption threshold value, the loss of the Compound Cavity being made up of Graphene and DFB reduces, and excitation threshold reduces instantaneously, forming centre wavelength is that the narrow-linewidth laser pulse of 1550 nanometers exports, and finally output terminal at wave division multiplex coupler exports.