CN104218449A

CN104218449A - Light source of high-capacity fiber Bragg grating sensing demodulating system

Info

Publication number: CN104218449A
Application number: CN201410049046.2A
Authority: CN
Inventors: 王嵚; 王江; 孙福林
Original assignee: Zhongke Rongtong Wulian Technology Wuxi Co Ltd
Current assignee: Zhongke Rongtong Wulian Technology Wuxi Co Ltd
Priority date: 2014-02-12
Filing date: 2014-02-12
Publication date: 2014-12-17

Abstract

The invention relates to a light source of a high-capacity fiber Bragg grating sensing demodulating system, in particular to a tunable circular laser comprising a semiconductor optical amplifier (SOA), two optical isolators, a broadband filter, a tunable F-P filter and a 1*2 optical coupler having a 40/60 splitting ratio. The output end of the semiconductor optical amplifier is connected to the first optical isolator through a fiber. The first optical isolator is connected to the tunable F-P filter through a fiber. The tunable F-P filter is connected to a first port of the 1*2 optical coupler through a fiber. A second port of the 1*2 optical coupler is connected to the second optical isolator through a fiber. The second optical fiber is connected to the broadband filter through a fiber. The broadband filter is connected to the input end of the semiconductor optical amplifier through a fiber. The 1*2 optical coupler outputs laser from the third port. The tunable circular laser is capable of outputting tunable circular fiber laser.

Description

A kind of large-capacity fiber grating sensing demodulating system light source

Technical field

The present invention relates to optical communication and technical field of optical fiber sensing, especially relate to fiber laser in the application of fiber Bragg grating sensor as light source, be i.e. a kind of tunable ring laser based on SOA.

Background technology

Utilize semiconductor optical amplifier (Semiconductor Optical Amplifier, SOA) by the annular cavity laser of optical fiber feedback formation, there is the advantage of many uniquenesses, there is higher average output power, Wavelength stabilized, stable high repetition frequency, makes it in optical fiber communication and all-optical signal processing technology, likely obtain potential extensive use, especially very promising at light sensory field.

The spontaneous emission spectrum that wide spectrum light source is generally sent by SOA is formed, SOA inject 350mA electric current time, the width of spontaneous emission spectrum is about about 100nm, and gross power is less than 2mW, be 600 for fineness, FSR is the F-P filter of 80nm, the spectrum width of output spectrum is generally at 0.13-0.16nm, in the region that SOA spontaneous emission spectrum is higher, the luminous power that each Wavelength Assignment arrives is only at 20-30 μ W, be assigned to each wavelength on multiple branch road and only have several μ W, the requirement of input and process can not be met far away; For the EDFA of single pumping, the power of spontaneous emission spectrum is generally at 30-50mW, and gain spectral is at 1530-1560nm, and the luminous power that each Wavelength Assignment arrives, only at 40-60 μ W, to be assigned on multiple branch road each wavelength also in μ W level.In optical fiber grating sensing engineering, if utilize traditional wideband light source, luminous power is less, the power be redistributed on each grating after arrowband F-P filter is less, and therefore the signal to noise ratio of system is not high, in practical engineering application, because channel fiber length is long, may loss to some extent, therefore can restriction system multiplexing capacity, thus the scale of restriction system.

Native system have employed ring laser configuration, semiconductor optical amplifier is SOA, its output spectrum is much wider than the bandwidth of filter, scope is about 60nm, F-P filter is under scanning voltage controls, whole wave-length coverage is scanned, when the reverberation wavelength of FBG and F-P filter transmitted light wave appearance simultaneously, then Output of laser.

Summary of the invention

For the defect that prior art exists, the object of the invention is to propose a kind of tunable ring laser, be intended to the output realizing tunable laser.

Technical scheme of the present invention is:

A kind of tunable ring laser, it is characterized in that comprising: semiconductor optical amplifier (SOA), two optical isolators, broadband filter, tunable TEA CO2 laser and splitting ratio are 1 × 2 optical coupler of 40/60, and described splitting ratio is 1 × 2 optical coupler of 40/60, there are three ports, its middle port one is unique input port, the output optical port of port 2 60%, and port three is the output optical port of 40%.Described semiconductor optical amplifier output by Fiber connection to optical isolator one, described optical isolator one by Fiber connection to tunable TEA CO2 laser, described tunable TEA CO2 laser is by the Single port of Fiber connection to 1 × 2 optical coupler, the Two-port netwerk of described 1 × 2 optical coupler by Fiber connection to optical isolator two, described optical isolator two by Fiber connection to broadband filter, described broadband filter by Fiber connection to the input of semiconductor optical amplifier.Three port Output of lasers of described 1 × 2 optical coupler.The present invention is based on SOA positive feedback loop, form saturation gain, piezoelectric ceramic is long for the chamber of modulating F-P filter, and then achieves the output of higher-wattage tunable laser.

Preferably, described semiconductor optical amplifier (SOA), two optical isolators, broadband filter, tunable TEA CO2 laser and splitting ratio be 40/60 1 × 2 optical coupler be the inclined device of all risk insurance.

Preferably, the described fiber coupler in the present invention is 1 × 2 coupled modes, and its splitting ratio is 40/60, also can determine according to practical application.

Preferably, the broadband filter spectrum width introduced in systems in which is about 75nm, makes the output wavelength of actual ring laser be limited to the scope of 1525 ~ 1600nm.

Preferably, in system, the free spectrum zone of F-P filter is 80nm, and fineness is 500 ~ 600.

Preferably, the electric current injected to described semiconductor optical amplifier (SOA) is about 250mA, and the laser power that ring laser exports is more than 12mW.

Preferably, the length of fiber optic loop is 2m, also can determine according to practical application.

Advantageous Effects of the present invention is:

Tunable ring laser provided by the invention, owing to only using simple annular structure, positive feedback loop, forms saturation gain, achieves the stable Laser output of higher-wattage.Because the chamber length of F-P filter is modulated by piezoelectric ceramic, achieve the tunable of Output of laser wavelength.Because the optics adopted is the inclined structure of all risk insurance, achieve stable single polarization state laser like this.

Accompanying drawing explanation

Fig. 1 is structural representation of the present invention.

Wherein: 1 is semiconductor optical amplifier (SOA), and 2 is optical isolator, and 3 is tunable TEA CO2 laser, 4 for splitting ratio be 1 × 2 optical coupler of 40/60,5 is optical isolator, and 6 is broadband filter, and 7 is piezoelectric ceramic.41 is the first port of coupler, and 42 is the second port of coupler, and 43 is the 3rd port of coupler.

The realization of the object of the invention, functional characteristics and advantage will in conjunction with the embodiments, are described further with reference to accompanying drawing.

Embodiment

The invention provides a kind of tunable ring laser, it is by semiconductor optical amplifier (SOA) 1, optical isolator 2, tunable TEA CO2 laser 3, splitting ratio is 1 × 2 optical coupler 4 of 40/60, optical isolator 5, broadband filter 6, piezoelectric ceramic 7 forms.Described coupler 4 is for being provided with three port coupler of the first port 41, second port the 42, three port 43.Described semiconductor optical amplifier output 11 by Fiber connection to optical isolator 2, described optical isolator 2 by Fiber connection to tunable TEA CO2 laser 3, described tunable TEA CO2 laser 3 is by the Single port 41 of Fiber connection to 1 × 2 optical coupler, the Two-port netwerk 42 of described 1 × 2 optical coupler by Fiber connection to optical isolator 5, described optical isolator 5 by Fiber connection to broadband filter 6, described broadband filter 6 by Fiber connection to the input 12 of semiconductor optical amplifier, the 3rd port 43 Output of laser of optical coupler.

Operation principle of the present invention is as follows: the output light of semiconductor optical amplifier 1 is by optical isolator 2, inject tunable TEA CO2 laser 3, the Single port 41 of 1 × 2 optical coupler is entered into by optical fiber, again by the Two-port netwerk of 1 × 2 optical coupler to optical isolator 5, and then through broadband filter 6, enter into the input 12 of semiconductor optical amplifier, like this, just define feedback loop, under considering that the internal loss degree of depth of semiconductor optical amplifier (SOA) is saturated, reach starting condition for oscillation (feedback threshold), detour some circles in fiber optic loop, form laser, finally exported by the 3rd port of coupler.Namely when injecting one to SOA and being greater than the direct current of its threshold current, SOA can produce amplification, and when the gain of SOA is greater than the loss of loop, ring laser exports the laser corresponding with the centre wavelength of F-P filter.PZT applies scanning voltage and controls tunable fiber type F-P filter, change ring laser output wavelength, reach the object using tunable TEA CO2 laser wide spectrum light source to be carried out to filtering.

The three dB bandwidth of laser spectroscopy is less than 0.05nm, close to laser spectroscopy during stable output, can not produce large error as scanning light source to the FBG reflectance spectrum gathered.Different at the numerical value of the three dB bandwidth of different wavelength zone laser spectroscopys, its scope is between 0.01 ~ 0.06nm.Compared with the method for wide spectrum light source being carried out to filtering with general use tunable TEA CO2 laser, the scanning optical spectrum of output is narrow, and the FBG reflectance spectrum collected accordingly is also narrow, and multiplexing grating quantity is increased.

Above-described embodiment is only illustrative rather than definitive thereof technical scheme of the present invention.Any technical scheme not departing from spirit and scope of the invention all should be encompassed in the middle of patent claim of the present invention.

Claims

1. a tunable ring laser, comprises semiconductor optical amplifier (SOA), two optical isolators, broadband filter, and tunable TEA CO2 laser and splitting ratio are 1 × 2 optical coupler of 40/60.Described splitting ratio is 1 × 2 optical coupler of 40/60, has three ports, and its middle port one is unique input port, the output optical port of port 2 60%, and port three is the output optical port of 40%.Described semiconductor optical amplifier output by Fiber connection to optical isolator one, described optical isolator one by Fiber connection to tunable TEA CO2 laser, described tunable TEA CO2 laser is by the Single port of Fiber connection to 1 × 2 optical coupler, the Two-port netwerk of described 1 × 2 optical coupler by Fiber connection to optical isolator two, described optical isolator two by Fiber connection to broadband filter, described broadband filter by Fiber connection to the input of semiconductor optical amplifier.Three port Output of lasers of described 1 × 2 optical coupler.

2. tunable ring laser according to claim 1, it is characterized in that described semiconductor optical amplifier (SOA), two optical isolators, broadband filter, tunable TEA CO2 laser and splitting ratio be 40/60 1 × 2 optical coupler be single mode device.

3. tunable ring laser according to claim 1, it is characterized in that in described semiconductor optical amplifier, inject the direct current being greater than its threshold current, SOA can produce amplification, and the gain of SOA is greater than loop loss.

4. tunable ring laser according to claim 1, it is characterized in that described broadband filter output wavelength is limited to 1525 ~ 1600nm scope, spectrum width is 75nm.

5. tunable ring laser according to claim 1, it is characterized in that the chamber length of described tunable TEA CO2 laser is regulated by piezoelectric ceramic (PZT), PZT applies scanning voltage, and PZT produces flexible, and the centre wavelength of F-P filter just changes thereupon.

6. tunable ring laser according to claim 1, it is characterized in that the free spectrum zone of described tunable TEA CO2 laser is 80nm, fineness is 500 ~ 600, use tunable TEA CO2 laser to carry out filtering to wide spectrum light source, the spectrum width of the scanning light source of output is 0.13 ~ 0.16nm.

Tunable ring laser according to claim 1, is characterized in that described its fiber optic loop formed totally 2 ~ 4m, to ensure that the laser delay time exported is for 500 ~ 1000ns.