Angular velocity detection method adopting bi-directional full reciprocal coupling optoelectronic oscillator

Patent metadata

Field	Value
Publication number	US-2016116288-A1
Application number	US-201514981808-A
Country	US
Kind code	A1
Filing date	Dec 28, 2015
Priority date	Sep 29, 2013
Publication date	Apr 28, 2016
Grant date	—

Abstract

The present invention provides an angular velocity detection method adopting a bi-directional full reciprocal coupling optoelectronic oscillator, which is implemented on an optical carrier microwave gyroscope. The optical carrier microwave gyroscope is a bi-directional resonant optical carrier microwave angular velocity measurement device sharing one optical fiber loop. The core of the method lies in that the Sagnac effect is sensed using a bi-directional optical carrier microwave resonant cavity, where the optical carrier microwave resonant cavity employs a coupling optoelectronic oscillator to achieve a bi-directional full reciprocal optical fiber path, and non-reciprocity error of the resonant cavity is eliminated effectively. The angular velocity detection method has features of high-precision, easy implementation and low costs.

First claim

What is claimed is:

1 . An angular velocity detection method adopting a bi-directional full reciprocal coupling optoelectronic oscillator, wherein the method can realize continuous measurement of angular velocity of a bi-directional resonant optical carrier microwave gyroscope, and the optical carrier microwave gyroscope comprises a 980 nm pump laser ( 1 ), a first 980/1550 wavelength division multiplexer ( 2 ), a polarization maintaining Erbium-doped optical fiber ( 3 ), a second 980/1550 wavelength division multiplexer ( 4 ), a control light drawing-out wire ( 5 ), an optical filter ( 6 ), a 45° polariscope ( 7 ), a polarization splitter/combiner ( 8 ), a first electro-optical modulator ( 9 ), a second electro-optical modulator ( 10 ), a first optical fiber coupler ( 11 ), a second optical fiber coupler ( 12 ), a beat signal detecting and processing circuit ( 13 ), an optical fiber annular cavity ( 14 ), a 90° connector ( 15 ), a first photodetector ( 16 ), a second photodetector ( 17 ), a first microwave regeneration mode locking control circuit ( 18 ), a second microwave regeneration mode locking control circuit ( 19 ), a first voltage controlled oscillator ( 20 ), and a second voltage controlled oscillator ( 21 );
a structure of the entire optical carrier microwave gyroscope is divided by the polarization splitter/combiner ( 8 ) into a loop part and a linear cavity part, and two sections of an optical fiber of the loop part are divided by the 90° connector ( 15 ) and are marked as L 1 and L 2 , respectively;
an optical path of the linear cavity part of the optical carrier microwave gyroscope is specifically: light output by the laser ( 1 ) controlled by a drive current is introduced into the polarization maintaining Erbium-doped optical fiber ( 3 ) for amplification after passing through the first 980/1550 wavelength division multiplexer ( 2 ), then the light is divided into two parts via the second 980/1550 wavelength division multiplexer ( 4 ), one part is control light, which is drawn out by the control light drawing-out wire ( 5 ), and the other part is work light, which continues to pass through frequency selective filtering of the optical filter ( 6 ) and its polarization state is rotated by 90° via reflection of the 45° polariscope ( 7 ), wherein light entering into the polarization splitter/combiner ( 8 ) comprises two work light beams of which polarization states are orthogonal (marked as a horizontal polarization state and a vertical polarization state respectively), and forms a clockwise resonant loop and a counterclockwise resonant loop at the loop part;
the clockwise resonant loop of the optical carrier microwave gyroscope is specifically: the light of vertical polarization state that enters into the polarization splitter/combiner ( 8 ) passes through the second electro-optical modulator ( 10 ) (non-modulated) in a clockwise direction (CW), then enters into the optical fiber annular cavity ( 14 ) via the second optical fiber coupler ( 12 ), and its direction of polarization is changed by 90° via the 90° connector ( 15 ), and is separated into two beams via the first optical fiber coupler ( 11 ) after being changed from vertical polarization light to horizontal polarization light, wherein one beam re-enters into the polarization splitter/combiner ( 8 ) to form the clockwise resonant loop after being modulated by the first electro-optical modulator ( 9 ); the other beam is introduced into the first photodetector ( 16 ), which converts an optical signal into a microwave signal, and subsequently is fed back via the first microwave regeneration mode locking control circuit ( 18 ) and the first voltage controlled oscillator ( 20 ) to control the first electro-optical modulator ( 9 ) performing frequency lock of the clockwise resonant loop;
the counterclockwise resonant loop of the optical carrier microwave gyroscope is specifically: the light of horizontal polarization state that enters into the polarization splitter/combiner ( 8 ) passes through the first electro-optical modulator ( 9 ) (non-modulated) and the first optical fiber coupler ( 11 ) in a counterclockwise direction (CCW), and its direction of polarization is changed by 90° via the 90° connector ( 15 ), then enters into the optical fiber annular cavity ( 14 ) after being changed from horizontal polarization light to vertical polarization light, and is separated into two beams via the second optical fiber coupler ( 12 ), wherein one beam re-enters into the polarization splitter/combiner ( 8 ) to form the counterclockwise resonant loop after being modulated by the second electro-optical modulator ( 10 ); the other beam is introduced into the second photodetector ( 17 ), which converts an optical signal into a microwave signal, and subsequently is fed back via the second microwave regeneration mode locking control circuit ( 19 ) and the second voltage controlled oscillator ( 21 ) to control the second electro-optical modulator ( 10 ) performing frequency lock of the counterclockwise resonant loop;
the method comprises the following steps:
step 1: after being introduced into the polarization maintaining Erbium-doped optical fiber ( 3 ) for amplification via the first 980/1550 wavelength division multiplexer ( 2 ), the horizontal polarization light emitted from the laser ( 1 ) is subjected to frequency selective filtering via the optical filter ( 6 ), and then is changed into vertical polarization light via reflection of the 45° polariscope ( 7 ) and returns back via the optical filter ( 6 ), the second 980/1550 wavelength division multiplexer ( 4 ), the polarization maintaining Erbium-doped optical fiber ( 3 ) and the first 980/1550 wavelength division multiplexer ( 2 ), which subsequently enters into the polarization splitter/combiner ( 8 ), and enters into the second electro-optical modulator ( 10 ), the second optical fiber coupler ( 12 ) and the optical fiber annular cavity ( 14 ) in a clockwise direction sequentially, then is changed into horizontal polarization light via the 90° connector ( 15 ), and then is reintroduced into the polarization maintaining Erbium-doped optical fiber ( 3 ) for amplification after entering into the first electro-optical modulator ( 9 ) for electro-optical modulation via the first optical fiber coupler ( 11 ), thereby forming the clockwise resonant loop;
after being introduced into the polarization maintaining Erbium-doped optical fiber ( 3 ) for amplification via the first 980/1550 wavelength division multiplexer ( 2 ), the vertical polarization light emitted from the laser ( 1 ) is subjected to frequency selective filtering via the optical filter ( 6 ), and then is changed into horizontal polarization light via reflection of the 45° polariscope ( 7 ) and returns back via the optical filter ( 6 ), the second 980/1550 wavelength division multiplexer ( 4 ), the polarization maintaining Erbium-doped optical fiber ( 3 ) and the first 980/1550 wavelength division multiplexer ( 2 ), which subsequently enters into the polarization splitter/combiner ( 8 ), and enters into the first electro-optical modulator ( 9 ) and the first optical fiber coupler ( 11 ) in a counterclockwise direction sequentially, then is changed into vertical polarization light via the 90° connector ( 15 ), and then passes through the optical fiber annular cavity ( 14 ) and the second optical fiber coupler ( 12 ) sequentially, which subsequently is reintroduced into the polarization maintaining Erbium-doped optical fiber ( 3 ) for amplification after entering into the second electro-optical modulator ( 10 ) for electro-optical modulation, thereby forming the counterclockwise resonant loop;
step 2: light in the clockwise resonant loop of the optical carrier microwave gyroscope passes through the first photodetector ( 16 ) to convert the optical signal into a microwave signal, which is subsequently introduced into the first microwave regeneration mode

Assignees

• Univ Zhejiang

Inventors

• Song Kaichen
• Yu Jinlong
• Ye Lingyun

Classifications

• G01C19/727 Primary

  using a passive ring resonator · CPC title

• G01C19/72 Primary

  with counter-rotating light beams in a passive ring, e.g. fibre laser gyrometers · CPC title