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

Patent metadata

Field	Value
Publication number	US-9568319-B2
Application number	US-201514981808-A
Country	US
Kind code	B2
Filing date	Dec 28, 2015
Priority date	Sep 29, 2013
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

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 1-1: forming the clockwise resonant loop, wherein the forming the clockwise resonant loop includes:
the horizontal polarization light emitted from the laser ( 1 ) is subsequently passed via the first 980/1550 wavelength division multiplexer ( 2 ), the polarization maintaining Erbium-doped optical fiber ( 3 ) for amplification, the optical filter ( 6 ) for frequency selective filtering, the 45° polariscope ( 7 ) for reflection into vertical polarization light, the optical filter ( 6 ), the second 980/1550 wavelength division multiplexer ( 4 ), the polarization maintaining Erbium-doped optical fiber ( 3 ), the first 980/1550 wavelength division multiplexer ( 2 ), and the polarization splitter/combiner ( 8 ), and is sequentially introduced into the second electro-optical modulator ( 10 ), the second optical fiber coupler ( 12 ), the optical fiber annular cavity ( 14 ), the 90° connector ( 15 ) for changing into horizontal polarization light, the first optical fiber coupler ( 11 ), the first electro-optical modulator ( 9 ) for electro-optical modulation and the polarization maintaining Erbium-doped optical fiber ( 3 ) for amplification in a clockwise direction, therefore the clockwise resonant loop is formed;
step 1-2: forming the counterclockwise resonant loop, wherein the forming the counterclockwise resonant loop includes:
the vertical polarization light emitted from the laser ( 1 ) is subsequently passed via the first 980/1550 wavelength division multiplexer ( 2 ), the polarization maintaining Erbium-doped optical fiber ( 3 ) for amplification, the optical filter ( 6 ) for frequency selective filtering, the 45° polariscope ( 7 ) for reflection into vertical polarization light, the optical filter ( 6 ), the second 980/1550 wavelength division multiplexer ( 4 ), the polarization maintaining Erbium-doped optical fiber ( 3 ), the first 980/1550 wavelength division multiplexer ( 2 ), and the polarization splitter/combiner 8 and is sequentially introduced into the first electro-optical modulator ( 9 ), the first optical fiber coupler ( 11 ), the 90° connector ( 15 ) for changing into vertical polarization light, the optical fiber annular cavity ( 14 ), the second optical fiber coupler ( 12 ), the second electro-optical modulator ( 10 ) and the polarization maintaining Erbium-doped optical fiber ( 3 ) for amplification in a counterclockwise direction, therefore the clockwise resonant loop is formed;
step 2-1: locking an oscillation frequency of the clockwise resonant loop, wherein the locking an oscillation frequency of the clockwise resonant loop includes:
light in the clockwise resonant loop is passed via the first photodetector ( 16 ) for generation of a resonant microwave signal, and the resonant microwave signal generated by the first photodetector ( 16 ) is subsequently passed via the first microwave reg

Assignees

• Univ Zhejiang

Inventors

• Song Kaichen
• Yu Jinlong
• Ye Lingyun

Classifications

• G01C19/72 Primary

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

• G01C19/727 Primary

  using a passive ring resonator · CPC title