Method and structure for diminishing signal interference of transmission path of optical fibre interference system

Abstract

A method for diminishing the signal interference of a transmission path of an optical fiber interference system, belonging to the technical field of optical fiber sensing. A wavelength division multiplexer (19) is connected in series to the end of an induced optical fiber, a wavelength component (2) is separated from an operating path by means of the wavelength division multiplexer (19) so as to measure a signal picked up by a transmission path, and the signal is removed from overall interference sensing signals by taking same as a reference, thereby obtaining a target measurement signal. Also provided is a structure for diminishing the signal interference of a transmission path of an optical fiber interference system. The method and the structure are simple; moreover, the device connected to the end of an induced optical fiber is passive, so that power supply is not required, and it is easy to implement. The present invention can be used for a sensing structure with a single measurement point and can be used in a sensing structure with a plurality of discontinuous measurement points as well.

Claims

1. A method for diminishing signal interference of a transmission path of an optical fiber interference system, comprising: using a WDM along an optical fiber transmission path in the optical fiber interference system to construct an original optical fiber transmission path and a new optical fiber transmission path, wherein the new optical fiber transmission path has an optical fiber path with sensing capability and only used for transmission, does not include a sensing unit, and has a same interference structure as the original optical fiber transmission path, and the interference structure of the original optical fiber path is located on the same optical fiber path as the interference structure of the new optical fiber path; and wherein a portion of wavelength component is separated from the original optical fiber path by the action of WDM to independently extract signals picked up by transmission path optical fiber, the signals are referenced to separate a target signal interfered by signals picked up by transmission path optical fiber.

2. The method according to claim 1, wherein, when the sensing unit is connected in the middle of the transmission optical fiber, and if a sensing unit is connected between a first transmission optical fiber and a second transmission optical fiber, wherein the sensing unit has two ports; using two WDMs, a first WDM (14) having a combined wave port and two partial wave ports, the output wavelengths are 1 and 2 respectively; a second WDM having a combined wave port and two partial wave ports, and the output wavelengths are 1 and 2 respectively; the first WDM is connected between the first transmission optical fiber and the sensing unit, the second WDM is connected between the sensing unit and the second transmission optical fiber; the first WDM, the second WDM, and the sensing unit construct a multiplexing unit; wherein the first transmission optical fiber is connected with the combined wave port of the first WDM, a first partial wave port of the first WDM is connected with a first port of the sensing unit, a second partial wave port of the first WDM is connected with a second partial wave port of the second WDM, a second port of the sensing unit is connected with a first partial wave port of the second WDM, the combined wave port of the second WDM is connected with the second transmission optical fiber; the light with wavelength 1 has passed along the first transmission path optical fiber.fwdarw.sensing unit.fwdarw.the second transmission optical fiber, while light with wavelength 2 avoids the sensing unit, and is directly transmitted to the second transmission optical fiber from the first transmission optical fiber.

3. The method according to claim 1, wherein, when the sensing unit is connected to the end of the transmission optical fiber, a WDM having a combined wave port and two partial wave ports, the output wavelengths are 1 and 2 respectively; a structural unit for constructing the complete interference construction is connected at the end of the optical fiber, the WDM is connected in series between a transmission optical fiber and a sensing unit; wherein the transmission optical fiber is connected with the combined wave port of the first WDM, a first partial wave port of the WDM is connected with the sensing unit, a second partial wave port of the WDM is connected with the structural unit, and wherein the WDM, the sensing unit, and the structural unit construct a multiplexing unit.

4. The method according to claim 3, wherein, the sensing unit is a feedback device and the structural unit has an interference structure that is the same as that of the sensing unit.

5. The method according to claim 3, wherein, the structural unit is a feedback device.

6. A structure for diminishing signal interference of transmission path of optical fiber interference system, wherein: a WDM is used along optical fiber transmission path in the optical fiber interference system to construct an original optical fiber transmission path and a new optical fiber transmission path; wherein an interference structure of the original optical fiber path is located on the same optical fiber path as an interference structure of the new optical fiber path the new optical fiber transmission path has an optical fiber path with sensing capability and only used for transmission, does not include a sensing unit, and has a same interference structure as the original optical fiber transmission path.

7. The structure according to claim 6, wherein, when the sensing unit is connected in the middle of the transmission optical fiber, and if the sensing unit is connected between a first transmission optical fiber and a second transmission optical fiber, the sensing unit having two ports; the structure comprising two WDMs, wherein a first WDM has a combined wave port and two partial wave ports, the output wavelengths are 1 and 2 respectively; a second WDM has a combined wave port and two partial wave ports, and the output wavelengths are 1 and 2 respectively; the first WDM is connected between the first transmission optical fiber and the sensing unit, the second WDM is connected between the sensing unit and the second transmission optical fiber; the first WDM, the second WDM, and the sensing unit construct a multiplexing unit; wherein the first transmission optical fiber is connected with the combined wave port of the first WDM, a first partial wave port of the first WDM is connected with a first port of the sensing unit, a second partial wave port of the first WDM is connected with a second partial wave port of the second WDM, a second port of the sensing unit is connected with a first partial wave port of the second WDM, the combined wave port of the second WDM is connected with the second transmission optical fiber.

8. The structure according to claim 6, wherein, when the sensing unit is connected to in an end of the transmission optical fiber, the structure comprises: a WDM having a combined wave port and two partial wave ports, the output wavelengths are 1 and 2 respectively; a structural unit for constructing the complete interference construction is connected at the end of the optical fiber, the WDM is connected in series between a transmission optical fiber and a sensing unit; wherein the transmission optical fiber is connected with the combined wave port of the first WDM, a first partial wave port of the WDM is connected with the sensing unit, a second partial wave port of the WDM is connected with the structural unit, and wherein the WDM, the sensing unit, and the structural unit construct a multiplexing unit.

9. The structure according to claim 8, wherein, the structural unit is a feedback device.

Description

BRIEF DESCRIPTION OF FIGURES

(1) FIG. 1 is an Optical fiber sensing apparatus for transmitting voice;

(2) FIG. 2 is an Optical sensing unit is connected to the middle of the transmission fiber connections. Wherein, (a) the original connection, (b) using the method of the present invention is illustrated in connection;

(3) FIG. 3 is an Optical sensing unit is connected to the end of the transmission fiber connections. Wherein, (a) the original connection, (b) using the method of the present invention is illustrated in connection;

(4) FIG. 4 is an Optical sensor system for sensing structure Sagnac ring interferometer structure shown. Wherein, (a) the original structure, (b) for the introduction of the present invention achieves a structure;

(5) FIG. 5 is an Optical sensor system for sensing structure single feedback interference structure icon. Wherein, (a) the original structure, (b) for the introduction of the present invention achieves a structure;

(6) FIG. 6 is using a single feedback free movement of surface structure measuring method of the present invention constituted.

REFERENCE NUMERAL

(7) 1,2,3,4,5 respectively 3*3 coupler port, 2*6,7,8 port coupler 2, the transmission optical fiber 9, 10 is coated with a highly reflective end surface of the Al film a microphone; a transmission optical fiber 11, 13, 12 of the optical fiber 11, 13 is connected between the sensing unit, 12a, 12b to the port 12 of the sensing unit; wavelength division multiplexer 14, 14a of a wavelength division multiplexer 14 the multiplexer (common), 14b, 14c of the wavelength demultiplexing ports, respectively, output 1, 2; 15 as wavelength division multiplexer, 15a multiplexer is a wavelength division multiplexer (common) 15, 15b, 15c for the sub-port wave output wavelength respectively 1, 2; 16A as wavelength division multiplexers 14 and 15, a multiplexing unit 12 sensing unit formed; transmission optical fiber 17, 18 of the sensing unit; 19 wavelength division multiplexer, a wavelength division multiplexer 19a to the multiplexer 19 (common), 19b, 19c for the sub-port wave output wavelength respectively 1, 2; 20 is connected to the end of the fiber, for a complete a structural unit of the interference structure; feedback unit 21, 16B for the wavelength division multiplexer 19, the sensing unit 18, a multiplexing unit 20 composed of the structural unit; optical splitter 22, a wavelength division multiplexer 23 is composed of spectroscopic unit; 24,26 for the spectroscopic device, an optical fiber delay unit 25, 27 is constituted WDM splitter unit; 3 28*3 equalization fused biconical tapered single-mode fiber coupler, wherein, 28a1,28a2, 28a3 in-phase port, 28b1,28b2 to the same port; 32 for the equalization of 2*2 single-mode optical fiber fused biconical tapered coupler, wherein, 32a1,32a2, in-phase port, 32b1,32b2 to the same port; 30, 31 are all WDM, a three-port device that has two ports splitting, 29a to reuse port 29, 29b, 29c for the splitting port 29, 30a to reuse port 30, 30b, 30c of the spectral port 30, 31a to reuse port 31, 31b, 31c of the spectral port 31; 33 as the probe 34 is freely movable surface having a reflecting function, a reflecting mirror 35.

Embodiment

(8) FIG. 6 is a single use feedback interferometer structure free surface of the optical structure vibration measurements. FIG. 28 is average 3*3 Optical Fiber tapered single-mode coupler, wherein, 28a1,28a2,28a3 phase for the same port, 28b1,28b2 to the same port; 32 for the equalization of 2*2 Optical Fiber pull tapered single-mode coupler, wherein, 32a1,32a2, in-phase port, 32b1,32b2 to the same port; 30, 31 are all WDM, a three-port device that has two ports spectroscopic multiplexing port 29a is 29, 29b, 29c for the 29 spectral port, 30a to 30 multiplexing port, 30b, 30c of the spectral of the port 30, 31a to 31 multiplexing port, 31b, 31c for the 31 spectral port; probe 33, 34 is freely movable surface having a reflecting function, a reflecting mirror 35.

(9) In this embodiment, along the transmission path 17 is transmitted to the probe light output by the probe 33, is incident to the free movement of surface 34, 34 after reflection by the free movement of surface, light re-enter the light probe 33 along the optical fiber path 17 original Road Back. In this measurement configuration, the sensor element can be seen as a combination of the free movement of the probe 33 and the surface 34, 17 although the ability to pick up external disturbance signal transmission path, but hopefully this is only part of the fiber transmission function to do so, according to the method of the invention, at the end, the use of wavelength division multiplexer 19, the light is divided into two portions wavelengths 1, 2, 1 walking port 19b is connected to the probe 33, a reflector port 35 is connected to walking lambda] 1.

(10) Wavelength light source as the center, respectively 1, 2 light, these two wavelengths of light through the wavelength division multiplexer 29, the combined input to the port coupler 28a1; the interference signal from the output port 28a2,28a3, respectively, then the wave drop multiplexer 30,31, 1, 2 light components are separated, the corresponding port output. In this configuration, two light transmission path of the interference beam relative to the wavelength 1 of:
P11: 28a1.fwdarw.28b1.fwdarw.25.fwdarw.32a1.fwdarw.32b1.fwdarw.17.fwdarw.19a.fwdarw.19b.fwdarw.33.fwdarw.34.fwdarw.33.fwdarw.19b.fwdarw.19a.fwdarw.17.fwdarw.32b1.fwdarw.32a2.fwdarw.28b2.fwdarw.28a2(28a3)
P12: 28a1.fwdarw.28b2.fwdarw.32a2.fwdarw.32b1.fwdarw.17.fwdarw.19a.fwdarw.19b.fwdarw.33.fwdarw.34.fwdarw.33.fwdarw.19b.fwdarw.17.fwdarw.32b1.fwdarw.32a1.fwdarw.25.fwdarw.28b1.fwdarw.28a2(28a3)

(11) Light transmission path interfering two beams of wavelength 2 is:
P21: 28a1.fwdarw.28b1.fwdarw.25.fwdarw.32a1.fwdarw.32b1.fwdarw.17.fwdarw.19a.fwdarw.19c.fwdarw.35.fwdarw.19c.fwdarw.19a.fwdarw.17.fwdarw.32b1.fwdarw.32a2.fwdarw.28b2.fwdarw.28a2(28a3)
P22: 28a1.fwdarw.28b2.fwdarw.32a2.fwdarw.32b1.fwdarw.17.fwdarw.19a.fwdarw.19c.fwdarw.35.fwdarw.19c.fwdarw.19a.fwdarw.17.fwdarw.32b1.fwdarw.32a1.fwdarw.25.fwdarw.28b1.fwdarw.28a2(28a3)

(12) Along the two beams P21 and P22 transmitted from the interfering signals obtained pure interference signal transmission path pickup P2; along the two beams P11 and P12 transmitted from the interfering signals obtained pure transmission path P1 signal picked up by the sensing unit and signal interference measurements. In this measuring arrangement, there

(13) $\begin{array}{cc}{}_{\mathrm{path}}\left({}_1,j\right)\frac{{}_2}{{}_1}{}_{\mathrm{path}}\left({}_2,j\right)& \left(7\right)\end{array}$

(14) 30, 31 from the WDM port output, using signal processing means to measure the target signal, that is, the free movement of the measurement signal is extracted surface 34.