CN202274928U

CN202274928U - Minisize fiber optical spectrum analyzer based on F-P filter

Info

Publication number: CN202274928U
Application number: CN2011203125424U
Authority: CN
Inventors: 姚飞; 陈溢文; 张超; 周晓伟
Original assignee: GUILIN G-LINK TECHNOLOGY Co Ltd
Current assignee: GUILIN G-LINK TECHNOLOGY Co Ltd
Priority date: 2011-08-25
Filing date: 2011-08-25
Publication date: 2012-06-13
Anticipated expiration: 2021-08-25

Abstract

The utility model discloses a minisize fiber optical spectrum analyzer based on an F-P filter, comprising a first shunt device, a first fiber grating and a second fiber grating, which are orderly connected with a broadband light source; and a switch, a second shunt device, a filter, a comprehensive processing unit and the broadband light source, which are orderly connected with a signal to be tested, wherein the first shunt device is connected with the second shunt device, and the comprehensive processing unit is connected with the switch. The minisize fiber optical spectrum analyzer is characterized in that the first and second fiber gratings are fiber Bragg gratings, the filter is an F-P filter, and the switch is an optical switch. Compared with the prior art, the minisize fiber optical spectrum analyzer based on an F-P filter has the characteristics of being small in size, light in mass, low in cost, convenient in modularization and easy in batch production, employs fiber gratings as real time calibration calibrating signals, thereby effectively increasing test precision, employs the advanced F-P filter as a shunt component, thereby providing reliable guarantee for the miniaturization of instruments, and employs the high speed optical switch as a signal switching switch, thereby enabling the real-time performance of test to be realized, overcoming the inherent problem of the F-P filter, and providing powerful guarantee for increasing test precision.

Description

A kind of mini optical fibre spectroanalysis instrument based on the F-P wave filter

Technical field

The utility model relates to the spectrum test field, a kind of mini optical fibre spectroanalysis instrument based on the F-P wave filter of saying so more specifically.

Background technology

Spectrometer is the important component part of optical instrument, and the different wave length signal that it comprises in can the resolved light signal is widely used in different field such as metallurgy, geology, oil, communication according to its test light wavelength coverage difference.The spectrometer test wave band that is applied to the communications field generally between 1250nm-1650nm, mainly can be divided into the material chromatic dispersion, stitch diffraction and three kinds of principles of multiple-beam interference more according to the beam split means.The utility model adopts the method for multiple-beam interference.

Development along with optical communication; To network transmission speed require increasingly high; Traditional SDH transmission system transfer rate is difficult to satisfy growing bandwidth demand; Dense wave division multipurpose (DWDM) system is transmitted a plurality of wavelength optical signals in an optical fiber, improved the utilization factor of optical fiber greatly, so the DWDM technology will be the inevitable technological means that solves the network transmission capacity problem.In optical communication field,, optical path analysis will be not only be confined to aspect the test and analysis of luminous power, and need in test result, showing the relevant information of different wave length signal in the light path along with the continuous development and the application of DWDM technology.Therefore, optical communication field is had higher requirement for spectrometer.One side need provide have more high precision, the instrument of wide-measuring range more; Press on the other hand a kind of miniaturization, intellectuality, stable and reliable for performance, moderate, can accomplish the instrument of test fast.

Spectrometer (OSA) separates (being called light filtering or beam split) with lightwave signal by the wavelength of its each ingredient, utilizes the corresponding light intensity of detecting device test different wave length, in particular range of wavelengths, checks the spectral profile figure of signal.The spectrometer that uses on the market at present mainly adopts diffraction grating as optical filter.Diffraction grating is a dispersive element, and its surface has the massive parallel fine rule, can be used for separate optical signals or is diffracted into spectrum.In case signal generation diffraction, the ad-hoc location that just can detecting device be aimed at diffraction spectrum is to measure the power of any setted wavelength.Measure another wavelength, detecting device just must be aimed at another wavelength location again, and the rest may be inferred.In order to test certain wavelength light intensity, detecting device must move on the position corresponding behind this wavelength light diffraction and carry out light-receiving in this method, and there is moving-member in system, for environment for use certain requirement is arranged.Diffraction grating itself is to portray a large amount of fine rules in the plane to process, and the instrument volume of the method development of employing diffraction grating is generally bigger.

Summary of the invention

The problem that the utility model will solve provides a kind of mini optical fibre spectroanalysis instrument based on the F-P wave filter, and this fibre optic spectral analyzer has that volume is little, test speed is fast, light weight, cost are low, be convenient to modularization, be easy to characteristics such as batch process.

A kind of mini optical fibre spectroanalysis instrument of the utility model based on the F-P wave filter; Comprise first shunt, first fiber grating, second fiber grating that are linked in sequence with wideband light source; The switch, second shunt, wave filter, overall treatment unit, the wideband light source that are linked in sequence with measured signal; In addition; First shunt is connected with second shunt, and the overall treatment unit is connected with switch, and different with prior art is: said first fiber grating and second fiber grating are Fiber Bragg Grating FBG; Wave filter is the F-P wave filter; Switch is a photoswitch.

The centre wavelength of said Fiber Bragg Grating FBG is two kinds of 1530nm and 1560nm.

Said Fiber Bragg Grating FBG (FBG:Fiber Bragger Gate) belongs to a kind of of uniform fiber grating; The variation in cycle vertically of its core refractive index of Fiber Bragg Grating FBG; When incident light acts on Fiber Bragg Grating FBG; Fiber Bragg Grating FBG can be with the light reflection of a certain specific wavelength, and the light of other wavelength does not then exert an influence.It is that 1530nm and centre wavelength are that 1560nm two fiber gratings are as calibrating signal that the utility model adopts centre wavelength.

Said F-P wave filter (FFP-TF; Fiber Fabry-Perot Tunable Filter) is a kind of optical filter that utilizes coherence's design of light; By the development of optics F-P interferometer, basic structure is that the two fiber end face collimations that are coated with high reflection layer are fixed, and makes to have a very little air chamber therebetween; When light gets into air chamber by an optical fiber, multiple-beam interference will take place in cavity.Long during when the chamber of F-P wave filter for a certain fixed value, have only the wavelength light that covers with a certain particular kind of relationship of foot with the chamber just can pass through, the light of other wavelength will be reflected; The chamber length of F-P wave filter is driven by piezoelectric ceramics (PZT); The voltage that is added on the PZT through change makes it produce small stretching, and drives chamber the changing of long hair of F-P wave filter, thereby changes the optical wavelength of transmission; Change F-P filter cavity through the continuous cycle is long, realizes the scanning to spectrum.

The utility model compared with prior art has that volume is little, light weight, cost are low, be convenient to modularization, be easy to characteristics such as batch process, utilize fiber grating as the real time calibration signal, effectively raise measuring accuracy; Adopt advanced F-P wave filter as light-splitting device, for instrument realizes that miniaturization provides reliable assurance; Adopt high-speed optical switch as signal shift switch, realized the real-time of test, the problem that remedied the intrinsic hysteresis that the F-P wave filter exists, wriggling property, need calibrate to test signal provides strong guarantee for improving measuring accuracy.

Description of drawings

Fig. 1 is the overall schematic of a kind of fibre optic spectral analyzer based on the F-P wave filter of the utility model.

Embodiment

Consult Fig. 1, this fiber spectrometer is made up of 8 parts, is respectively: wideband light source 1, first shunt 2, second shunt 3, first fiber grating 4, second fiber grating 5, photoswitch 6, F-P wave filter 7, overall treatment unit 8.The utility model is added in the driving voltage on the F-P wave filter 7 through the change in cycle, realizes the spectral scan of F-P wave filter 7; Realize the real time calibration of spectrometer test through the switching of photoswitch 6, thereby improve the precision of test.The transmission sawtooth voltage signal in 8 continuous cycles of overall treatment unit is as the drive signal of F-P wave filter 7.

In first scan period of F-P wave filter 7 (test period); Open photoswitch 6; And close wideband light source 1, make light signal to be measured get into F-P wave filter 7, along with the continuous variation of driving voltage through the photoswitch 6 and second shunt 3; Wavelength optical signals gets into overall treatment unit 8 with priority through F-P wave filter 7 in the measured signal, and overall treatment unit 8 is with the data of sampling and the driving voltage opening relationships and the storage of output.In second scan period of F-P wave filter 7 (calibration cycle); Overall treatment unit 8 sends control signal; Turn-off photoswitch 6; Make measured signal can't get into optical system for testing, drive wideband light source 1 work simultaneously, the broadband light that wideband light source 1 sends gets into the grating array of being made up of first fiber grating 4 and second fiber grating 5 through first shunt 2; Satisfy light reflected back second shunt 3 of the wavelength of optical grating reflection condition in the wideband light source 1, the light signal of other wavelength components is then clog-free thoroughly to be passed through.The light signal of reflected back second shunt 3 is single wavelength light of the conditioned reflex of satisfied first fiber grating 4 and second fiber grating 5, and they have constituted calibrating signal, gets into F-P wave filters 7 through second shunt, 3 backs.F-P wave filter 7 through scanning obtain calibrating signal through the time driving voltage value, and set up driving voltage and the relation of calibrating between the wavelength.

Through first scan period, obtained the relation between different transmission peak wavelengths of light signal to be measured and driving voltage.Because it is non-linear that F-P wave filter 7 exists, can't get the explicit value of test result medium wavelength.Through second scan period, obtain the relation between calibrating signal and driving voltage, confirm to obtain data in first scan period as reference.Concrete grammar is following: because calibrating signal is 1530nm and 1560nm light signal for fixing centre wavelength, if their corresponding driving voltage is respectively V1 and V2, then the pairing optical wavelength L of certain magnitude of voltage V in a scan period should satisfy following formula:

Can calculate the corresponding light wave long value in all voltage places with this formula; The intensity level I that obtains according to test again at this voltage V place; Set up the relation between the optical wavelength and intensity in the measured signal; After these corresponding relations are all confirmed, being horizontal ordinate with the wavelength, is the spectrogram that ordinate just can obtain light signal to be measured with intensity.

Claims

1. mini optical fibre spectroanalysis instrument based on the F-P wave filter; Comprise first shunt, first fiber grating, second fiber grating that are linked in sequence with wideband light source; With switch, second shunt, wave filter, overall treatment unit, wideband light source that measured signal is linked in sequence, in addition, first shunt is connected with second shunt; The overall treatment unit is connected with switch, it is characterized in that: said first fiber grating and second fiber grating are Fiber Bragg Grating FBG; Wave filter is the F-P wave filter; Switch is a photoswitch.