Bidirectional optical-carrying microwave resonance system based on circulator structure and method for detecting angular velocity by said system

Patent metadata

Field	Value
Publication number	US-11874113-B2
Application number	US-202117244965-A
Country	US
Kind code	B2
Filing date	Apr 30, 2021
Priority date	Oct 31, 2018
Publication date	Jan 16, 2024
Grant date	Jan 16, 2024

Abstract

A bidirectional optical-carrying microwave resonance system based on a circulator structure and a method for detecting angular velocity by said system. A high-stability optical-carrying microwave of which polarization states in forward and reverse directions are perpendicular is generated in an optical fiber ring by utilizing a regenerative mold locking technology, a cavity length control technology, and a polarization state separation technology, and the optical-carrying microwave is used for measuring a rotational angular velocity. The circulator structure is adopted and the bidirectional optical-carrying microwave resonance is achieved by means of a bidirectional regenerative mode locking technology. A reciprocal bidirectional optical-carrying microwave resonance system is achieved on the basis of a non-reciprocal error elimination technology of a wide-spectrum optical interferometer. The polarization state separation technology is adopted to achieve dual-wavelength separation of optical signals and the perpendicular polarization state is adopted for opposite transmission in a sensitive ring, so that the detection capability of the sensitive ring is improved. The cavity length control technology is adopted to lock a microwave oscillation frequency in one direction to a high-stability standard-time reference source, so that a relative cavity length of an optical resonant cavity is stabilized. The system has the characteristics of high practicability, high measurement precision and the like.

First claim

What is claimed is:

1. A bidirectional microwave-over-fiber resonant system based on a circulator structure, comprising a broadband spectrum light source ( 1 ), a 50:50 coupler ( 2 ), a first wavelength division multiplexer ( 3 ), a second wavelength division multiplexer ( 4 ), a low speed photoelectric converter ( 5 ), an interferometer controller ( 6 ), a cavity length compensation adjuster ( 7 ), a first optical amplifier ( 9 ), a first photoelectric intensity modulator ( 10 ), a first optical circulator ( 11 ), a first optical coupler ( 12 ), a narrowband bidirectional optical filter ( 13 ), a second optical coupler ( 16 ), a second optical amplifier ( 17 ), a second photoelectric intensity modulator ( 18 ), a second optical circulator ( 19 ), a first regenerative cavity cavity-length adjuster ( 20 ), a first high speed photoelectric detector ( 21 ), a first microwave filtering and amplifying unit ( 22 ), a first microwave power divider ( 24 ), a second regenerative cavity cavity-length adjuster ( 25 ), a second high speed photoelectric detector ( 26 ), a second microwave filtering and amplifying unit ( 27 ), a sensing ring interferometer structure ( 29 ), a second microwave power divider ( 46 ), a third microwave power divider ( 47 ), and a difference frequency detection unit ( 48 );
wherein the first optical amplifier ( 9 ), the first photoelectric intensity modulator ( 10 ), the cavity length compensation adjuster ( 7 ), the first optical circulator ( 11 ), the second wavelength division multiplexer ( 4 ), the first optical coupler ( 12 ), the narrowband bidirectional optical filter ( 13 ), the sensing ring interferometer structure ( 29 ), the second optical coupler ( 16 ), the first wavelength division multiplexer ( 3 ) and the second optical circulator ( 19 ) are connected in sequence to form a clockwise ring resonant cavity; resonant light in a clockwise direction passes sequentially through the first optical coupler ( 12 ), the second regenerative cavity cavity-length adjuster ( 25 ), the second high speed photoelectric detector ( 26 ), the second microwave filtering and amplifying unit ( 27 ), and the third microwave power divider ( 47 ) to be fed back and modulated by the first photoelectric intensity modulator ( 10 ), so as to constitute a clockwise regenerative mode-locked structure; an electric signal generated by the clockwise regenerative mode-locked structure is input into the difference frequency detection unit ( 48 ) through the third microwave power divider ( 47 );
wherein the second optical amplifier ( 17 ), the second photoelectric intensity modulator ( 18 ), the second optical circulator ( 19 ), the first wavelength division multiplexer ( 3 ), the second optical coupler ( 16 ), the sensing ring interferometer structure ( 29 ), the narrowband bidirectional optical filter ( 13 ), the first optical coupler ( 12 ), the second wavelength division multiplexer ( 4 ) and the first optical circulator ( 11 ) are connected in sequence to form a counterclockwise ring resonant cavity; resonant light in a counterclockwise direction passes sequentially through the second optical coupler ( 16 ), the first regenerative cavity cavity-length adjuster ( 20 ), the first high speed photoelectric detector ( 21 ), the first microwave filtering and amplifying unit ( 22 ), the first microwave power divider ( 24 ), and the second microwave power divider ( 46 ) to be fed back and modulated by the second photoelectric intensity modulator ( 18 ), so as to constitute a counterclockwise regenerative mode-locked structure; an electric signal generated by the counterclockwise regenerative mode-locked structure is input into the difference frequency detection unit ( 48 ) via the second microwave power divider ( 46 );
wherein the broadband spectrum light source ( 1 ), the 50:50 coupler ( 2 ), the first wavelength division multiplexer ( 3 ), the second wavelength division multiplexer ( 4 ), the low speed photoelectric converter ( 5 ), the interferometer controller ( 6 ) and the cavity length compensation adjuster ( 7 ) constitute a reciprocity error compensation broadband spectrum optical interferometer with double loops in clockwise and counterclockwise directions; light emitted by the broadband spectrum light source ( 1 ) is divided into two arms via the 50:50 coupler ( 2 ), wherein a first arm passes in sequence through the second wavelength division multiplexer ( 4 ), the first optical circulator ( 11 ), the second optical amplifier ( 17 ), the second photoelectric intensity modulator ( 18 ), the second optical circulator ( 19 ), the first wavelength division multiplexer ( 3 ), the 50:50 coupler ( 2 ) to enter the low speed photoelectric converter ( 5 ); a second arm passes in sequence through the first wavelength division multiplexer ( 3 ), a second optical circulator ( 19 ), a first optical amplifier ( 9 ), a first photoelectric intensity modulator ( 10 ), the cavity length compensation adjuster ( 7 ), the first optical circulator ( 11 ), the second wavelength division multiplexer ( 4 ), the 50:50 coupler ( 2 ) to enter the low speed photoelectric converter ( 5 ); a detection signal of the low speed photoelectric converter ( 5 ) passes through the interferometer controller ( 6 ) and is output to control the cavity length compensation adjuster ( 7 ) to achieve a same optical path in both arms of the broadband spectrum optical interferometer and eliminate non-reciprocal errors caused by non-bidirectional devices on both arms; the light emitted by the broadband spectrum light source ( 1 ) does not interfere with the resonant light in the clockwise direction and the counterclockwise direction;
the sensing ring interferometer structure ( 29 ) comprises a first orthogonal polarization state adjusting unit ( 37 ), a polarization beam splitter ( 38 ), a fiber sensing ring ( 39 ) and a second orthogonal polarization state adjusting unit ( 40 );
the resonant light in the clockwise direction passes through the first orthogonal polarization state adjustment unit ( 37 ) to adjust a double-peaked spectral signal of the narrowband bidirectional optical filter ( 13 ) to two paths of signals with perpendicular polarization states; and the two paths of signals enter the fiber sensing ring ( 39 ) via the polarization beam splitter ( 38 ), and pass through the polarization beam splitter ( 38 ) and the second orthogonal polarization state adjustment unit ( 40 ) to adjust the polarization states back to an initial state;
the resonant light in the counterclockwise direction passes through the second orthogonal polarization state adjustment unit ( 40 ) to adjust the double-peaked spectral signal of the narrowband bidirectional optical filter ( 13 ) to two paths of signals with perpendicular polarization states; and the two paths of signals enter the fiber sensing ring ( 39 ) via the polarization beam splitter ( 38 ), and pass through the polarization beam splitter ( 38 ) and the first orthogonal polarization state adjustment unit ( 37 ) to adjust the polarization states back to an initial state.

2. The bidirectional microwave-over-fiber resonant system based on the circulator structure according to claim 1 , wherein microwave signals generated by the clockwise regenerative mode-locked structure and the counterclockwise regenerative mode-locked structure are input into the difference frequency detection unit ( 48 ) to detect an angular velocity.

3. The bidirectional microwave-over-fiber resonant system based on the circulator structure according to claim 1 , wherein the narrowband bidirectional optical filter ( 13 ) changes a resonant microwave-over-fiber signal when the system is operated into a double-peaked spectral signal to achieve bidirectional dual-frequency resonance; wavelengths corresponding to spectral peaks are λ 1 and λ 2 respectively, and a frequency difference between λ 1 and λ 2 is a modulat

Assignees

• Univ Zhejiang

Inventors

• Song Kaichen
• Yu Jinlong
• Ye Lingyun
• Wang Ju

Classifications

• G01C19/722 Primary

  of the mechanical construction · CPC title

• G02B27/283

  used for beam splitting or combining · CPC title

• G01C19/72 Primary

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

• G01C19/727

  using a passive ring resonator · CPC title