CN2653525Y - Optic fiber grating type wave length adjusting OADM device with temperature controller - Google Patents

Abstract

The utility model provides a fiber optical raster wave length toning OADM device that is provided with a temperature control device and relates to optical components with temperature compensation in optical communication system, in particular to a fiber optical raster wave length toning OADM device that is provided with a temperature control device. The utility model provides a fiber optical raster wave length toning OADM device that is provided with a temperature control device. The temperature control device can automatically compensate temperature for the OADM device. The technical proposal is: the utility model comprises a ring shaped device, a fiber optical raster, a couplet and a wave length toning unit. The utility model is characterized in that: the utility model also comprises a controllable heating source that is fixed on and connected with the wave length adjusting unit, a layer of soaking material is arranged between the heating source and the wave length toning unit. The utility model is used in temperature compensation of various fiber optical raster to make the tunable harmonic temperature stability index of the fiber optical raster meet actual application demand.

Description

The fiber Bragg grating type wavelength adjustment 0ADM device of band attemperating unit

Technical field

The utility model relates to the optical device of band temperature compensation in a kind of optical communication system, relates in particular to the fiber Bragg grating type wavelength adjustment OADM device of band attemperating unit.

Background technology

Optical add/drop multiplexer (Optical Add/Drop Multiplexer 0ADM) is one of important node equipment in the all-optical network, it has realized that the setted wavelength light signal is downloaded in wavelength-division multiplex (WDM) system on some node station, all the other wavelength light signals are then impregnable directly to be passed through.Have the people to propose up and down road of wavelength since nineteen ninety, up to the present, people have proposed the scheme of a variety of OADM, according to the filtering device difference that adopts, existing OADM can be divided into fiber grating (FBG) formula, and list of references is seen Feng Dejun, Liu Heliang, Qin Zixiong opens Gui Yun, Yuan Shuzhong, Liu Zhiguo, Dong Xiaoyi, " based on the tunable wave length optical add/drop multiplexer of fiber grating ", " photon journal ", 2001, Vol.30, No.1, pp43-46; Film (DTMF) formula, list of references is seen J.Minowa and Y.Fujii, " Dielectric Multilayer Thin-film Filters for WDMTransmission Systems ", J.Lightwave Tech., Vol.LT-1, Mar.1983:116-121.; Array waveguide grating (AWG) formula, list of references is seen Yoshiaki Tachikawa, Yasuyuki Inoue, Motohaya Ishii, Toshinori Nozawa, " Arrayed waveguide grating multiplexer with loop back opticalpaths and its applications ", Journal of Lightwave Technology, 14, pp.977, (1996)..The performance of these OADM depends primarily on the performance of the filtering device that is adopted, and sees Rajiv Ramaswami, KumarN.Sivarajan, " Optical Networks, Book1 ", Morgan Kaufmann Publishers, Inc., 1998..Fiber Bragg grating type OADM is with its low insertion loss (the insertion loss of fiber grating itself is about 0.2dB), and high channel isolation (up to 40dB) is specially adapted to narrow interval (being not more than 0.8nm) dwdm system, becomes the research focus.

Channel center's wavelength of optical fiber Bragg raster formula OADM is the Bragg wavelength of grating.The ITU-T standard has clear and definite regulation to the wavelength under the various intervals of wdm system use.In the reality, prepare the fiber grating that meets ITU-T standard wavelength is the comparison difficulty, because each stages operating of fiber grating preparation all can influence the Bragg wavelength.In site of deployment, also there is alignment issues in the centre wavelength of each producer's equipment room in addition.Therefore OADM should have the fine-tuning attribute of centre wavelength.The part scholar studies the tuning performance of fiber Bragg grating type OADM at present, obtained good experimental index, document A.locco sees reference, H.G.Limberger and R.P.Salathe, " Bragg Grating Fast Tunable Filter for WavelengthDivision Multiplexing ", J.Lightwave Tech., Vol.17, Aug.1999:1217-1221 and list of references G.A Balland W.W.Morey, " Compression-Tuned Single-Frequency Bragg Fiber Laser ", Opt.Lett., 19 (23), 1994:1979～1981..Another problem that exists in the fiber Bragg grating type OADM research is a temperature stability, because the centre wavelength of grating can vary with temperature (thermal expansivity of naked grating is 0.01nm/ ℃).The compensation for the temperature drift of Fiber Bragg Grating FBG centre wavelength at present mainly contains two kinds of methods, document R.Kashyap sees reference, M.H.Reeve, S.A.Cassidy, et al., " Temperature Desensitisation of Delay in Fibers ", UK PatentNO.8328204.21 Oct.1983.; And list of references W.W.Morey and W.L.Glomb, " Incorporated BraggFilter Temperature Compensated Optical Waveguide Device ", US Patent No.5042898,27Aug.1991; All be to utilize encapsulating material with different temperature coefficients.Grating is placed the encapsulation that has the material formation of different heat expansion coefficient with two kinds, make the temperature coefficient of fiber grating drop to 0.07nm/100 ℃, the document G.W.Yoffe that sees reference, Peter A, F.Ouellette, and D.A.Thorncraft, " Passive temperature-compensatingpackage for optical fiber gratings ", APPLIED OPTICS, Vol.34, No.30,20 October1995.Yet said method is mostly at the fixed wave length fiber grating, and the grating that compensated through said method all is non-tunable.The tunability of centre wavelength and temperature stability are a pair of contradiction, should accomplish that tunable to satisfy the high-temperature stability requirement again be a present difficult problem also to be solved.

Summary of the invention

For overcoming the deficiencies in the prior art, the purpose of this utility model is: the fiber Bragg grating type wavelength adjustment OADM device that the band attemperating unit is provided, described attemperating unit can carry out temperature compensation automatically to the OADM device, makes OADM device working stability in certain temperature range.

For achieving the above object, the technical solution adopted in the utility model is: the fiber Bragg grating type wavelength adjustment OADM device of band attemperating unit, by circulator, fiber grating, coupling mechanism and wavelength regulation mechanism form, comprise controlled heating source in addition, controlled heating source is fixedly connected in the wavelength regulation mechanism, at controlled heating source and the inter-agency equal hot material of one deck that is provided with of wavelength regulation.

Wherein, described controlled heating source comprises heater element and the control circuit that mainly is made of variable resistor, sensor;

Described equal hot material is a mylar;

Described heater element is flange-cooled electron device.

Because the utility model has adopted the equal hot material of the inter-agency one deck that is provided with of controlled heating source and controlled heating source and wavelength regulation, thereby can carry out the even temperature compensation to the OADM device, because the control circuit that adopts sensor, variable resistor to constitute, thereby this compensation is carried out within the specific limits automatically.In addition, heater element adopts flange-cooled electron device, makes the utility model also have characteristics simple in structure, with low cost.

Description of drawings

Fig. 1 OADM device fundamental diagram

Fig. 2 wavelength regulation mechanism, all hot material and controlled heating source graph of a relation, and book extract accompanying drawing as an illustration, among the figure: 1 is wavelength regulation mechanism, and 2 is equal hot material, and 3 is controlled heating source.

Fig. 3 1550.92～1553.32 4 wavelength input

Fig. 4 the 1 road downloads end spectral property figure

Fig. 5 the 2 road downloads end spectral property figure

Fig. 6 the 3 road downloads end spectral property figure

Fig. 7 the 4 road downloads end spectral property figure

Fig. 8 channel center wavelength is with the variation diagram of environment temperature

Fig. 9 is controlled heating source shop drawing

Embodiment

Below in conjunction with drawings and Examples, further specify the utility model.

In the present embodiment, the fiber Bragg grating type OADM unit of realizing as shown in Figure 1, whole unit is by 43 end circulator C1, C2, C3, C4,4 fine-tuning optical fiber Bragg raster FBG1 of wavelength, FBG2, FBG3, FBG4, a 4 * 1Mux and one 2 * 1 coupling mechanism Coupler form, Drop1, Drop2, Drop3, Drop4 are following road signal, and Add1, Add2, Add3, Add4 are the signal of setting out on a journey.Circulator C1 arrives port 2a with the optical signal transmission of its port one a input, and the light transmission of port 2a input is to port 3a.Tunable fiber grating FBG1 is to the light λ of the setted wavelength of the port 2a output of C1 ₁Carry out total reflection and get back to port 2a, realized one road setted wavelength light signal λ ₁Download, and make the light λ of its commplementary wave length _2,3...nThe straight-through circulator C2 that arrives.Similarly, circulator C2 and grating FBG 2, circulator C3 and grating FBG 3 and circulator C4 and grating FBG 4 are realized λ respectively ₂, λ ₃And λ ₄Download and other wavelength straight-through.Simultaneously, λ ₂, λ ₃And λ ₄Upload by 2 coupling mechanisms, 4 * 1Mux among the figure and Coupler realize.

Fiber grating is sticked in the wavelength regulation mechanism.In the present embodiment, governor motion is a semi-girder, adopts the semi-girder tuning methods that the centre wavelength of fiber grating is finely tuned aligning.The temperature stability of fiber grating is on the one hand from the temperature performance of grating itself like this, on the other hand then from the temperature characterisitic of beam material.The bragg grating wavelength closes with variation of temperature:

$\frac{\mathrm{\Δ}{\mathrm{\λ}}_B}{{\mathrm{\λ}}_B}=(\mathrm{\α}+\mathrm{\ξ})\mathrm{\ΔT}+(1-P_e)\mathrm{\ϵ}\·\·\·\left(1\right)$

Wherein α is the thermal expansivity of fiber optic materials, and ξ is a thermo-optical coeffecient, p _eBe the strain optical coefficient of fiber optic materials, ε is that fiber axis is to dependent variable.If semi-girder material coefficient of thermal expansion coefficient is α ₁, the pass of the length strain of semi-girder and temperature variation is ε so ₁=α ₁Δ T.Suppose that optical fiber optical grating stress compares and can ignore with the stress of tuning beam, can be similar to and know the temperature sensitivity that adheres to the fiber grating on the semi-girder by inference and be:

$\frac{\mathrm{\Δ}{\mathrm{\λ}}_B}{{\mathrm{\λ}}_B}=(\mathrm{\α}+\mathrm{\ξ})\mathrm{\ΔT}+(1-p_e){\mathrm{\α}}_1\mathrm{\ΔT}\·\·\·\left(2\right)$

To obtain little Δ λ as can be known by following formula _B, should select thermalexpansioncoefficient ₁As far as possible little beam material, but the little elastic properties of materials of thermal expansivity is also little, thus cause tuning range to diminish.Take all factors into consideration the elasticity and the temperature stability of semi-girder, the indium steel (5 * 10 with relatively low thermel expansion coefficient is selected in experiment for use ^-6/ ℃).Experiment shows: fiber grating adheres to this kind Liang Shanghou, and wavelength is 0.027nm/ ℃ with variation of temperature.When environment temperature changed in-20 ℃ ~+60 ℃ scopes, total wavelength shift was 2.16nm near the fiber grating 1550nm.For being spaced apart the dwdm system of 0.8nm, this means that the centre wavelength of channel has moved on to adjacent channel, will cause the deterioration of channel index.For further improving temperature stability, design a kind of attemperating unit that is particularly suitable for the tuning grating of semi-girder, be attached to the side of semi-girder.

As shown in Figure 2, wavelength regulation mechanism 1 and paste fiber grating, controlled heating source 3 in the above and be arranged on the fine-tuning optical fiber Bragg raster FBG1 of wavelength in equal hot material 2 composition diagrams 1 between controlled heating source 3 and the wavelength regulation mechanism 1, controlled heating source 3 comprises heater element and the control circuit that mainly is made of sensor, variable resistor, wherein, controlled heating source 3 and equal hot material 2 constitute attemperating units, and described heater element is flange-cooled electron device.Described equal hot material is a mylar.Controlled heating source 3 is fixedly connected in the wavelength regulation mechanism 1, and specifically, described heat radiator sticks on the equal hot material 2, and all hot material sticks on wavelength regulation mechanism 1 side.FBG2 among Fig. 1, FMG3, FBG4 are identical with the FBG1 structure, do not repeat them here.

Fig. 9 is controlled heating source shop drawing, and variable resistor R, sensor Rs, resistance R 1 and resistance R 2 are formed electric bridge, and temperature control point is set by variable resistor R.Suppose that temperature control point is X ℃, when environment temperature is lower than X ℃, this temperature variation of sensor Rs perception, and make electric bridge generation signal output to comparer, comparer produces signal thus to electron device, electron device heats by its heat radiator, makes the temperature of wavelength tuning mechanism 1 remain on X ℃, thereby plays temperature compensation function.Electron device can be triode or other flange-cooled similar device.Characteristics of the present utility model are that volume is little, are about 50mm * 18mm * 1.5mm, and power consumption is lower than 3 watts.Realized local temperature control, reached the temperature stability that requires fiber grating.

This OADM is tested, and four road circular cavity optic fibre laser output wavelengths are respectively λ ₁=1550.92nm, λ ₂=1551.72nm, λ ₃=1552.52nm and λ ₄=1553.32nm, the wavelength interval is 0.8, meets ITU-T and G.692 advises, synthesizes one the tunnel through wave multiplexer, is input to the input end of OADM, signal spectrum is as shown in Figure 3.The download end Drop1 of OADM, Drop2, Drop3 and Drop4 receive the input end of spectrometer MC9710B respectively, obtain downloading the end spectral property, as Fig. 4-shown in Figure 7.As can be seen, the channel spacing of 4 road OADM is 0.8nm from Fig. 4 to Fig. 7, and 3dB channel bandwidth in road meets the requirement of ITU-TG.692 less than 0.3nm up and down; Adjacent Channel Isolation is 35dB, and this index depends primarily on the good filtering characteristic of fiber grating.Insertion loss that it should be noted that this each download channels of OADM increases successively, and this is because each circulator of series connection, fiber grating and fusing due to a little insertion loss accumulates.This in principle loss accumulation is inevitably, but as long as with the insertion loss control of each link to minimum, whole insertion loss can be controlled in below the 6dB.

The used instrument of temperature experiment has the electric heating temperature-controlled cabinet, self-control wideband light source and spectrometer MC9710B.By-20 ℃～+ 60 ℃ variation of ambient temperature of electric heating temperature-controlled cabinet simulation.To wavelength is that the channel of 1550.92nm carries out temperature experiment, records tunable optical fiber Bragg grating centre wavelength with the variation of temperature curve as shown in Figure 8.Curve 1 is that it is linear that change curve is not with the situation of temperature compensation.Total wave length shift is 2.16nm in 80 ℃ of scopes, and the mean wavelength drift is for 0.027nm/ ℃.Curve 2 is the situation through temperature compensation, and when temperature was lower than 50 ℃, wavelength varied with temperature hardly; When temperature was higher than 50 ℃, channel center's wavelength was linear change with temperature.The total drift of channel center's wavelength is 0.31nm, and the mean wavelength drift is 0.004nm/ ℃, and comparing temperature degree stability with not temperature compensated situation has improved 6.75 times, satisfied application request 0.01nm/ ℃.

Fiber grating sticks on the fine setting that realizes on the semi-girder its centre wavelength, but the introducing of beam has further increased the instability (for 0.027nm/ ℃) of grating temperature, in order to solve the contradiction of wavelength tuning and temperature stability, the utility model proposes a kind of fine-tuning OADM of fiber Bragg grating type wavelength with attemperating unit, the test result of this OADM is: in ambient temperature range-20 ℃ ~+60 ℃, center wavelength variation is less than 0.004nm/ ℃, compare with the tuning grating of not temperature compensated semi-girder, 6.75 times have been improved, 0.01nm/ ℃ requirement when being better than practical application.Use the semi-girder method, obtained the tuning amount of centre wavelength of 1nm, realized the function of wavelength alignment.The channel spacing of 4 road OADM is 0.8nm, and 3dB channel bandwidth in road meets ITU-T requirement G.692 less than 0.3nm up and down; Adopt homemade grating, realized the Adjacent Channel Isolation of 35dB.

Claims (4)

1, the fiber Bragg grating type wavelength adjustment OADM device of band attemperating unit, by circulator, fiber grating, coupling mechanism and wavelength regulation mechanism form, it is characterized in that, also comprise controlled heating source, controlled heating source is fixedly connected in the wavelength regulation mechanism, at controlled heating source and the inter-agency equal hot material of one deck that is provided with of wavelength regulation.

2, the accurate OADM device of the fiber Bragg grating type wavelength-tunable of band attemperating unit according to claim 1 is characterized in that, described controlled heating source comprises heater element and the control circuit that mainly is made of variable resistor, sensor.

3, the accurate OADM device of the fiber Bragg grating type wavelength-tunable of band attemperating unit according to claim 1 is characterized in that, described equal hot material is a mylar.

4, the accurate OADM device of the fiber Bragg grating type wavelength-tunable of band attemperating unit according to claim 2 is characterized in that, described heater element is flange-cooled electron device.

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