Title:
過変調を採用している光ファイバ・ジャイロスコープにおけるクロスカップリングを抑制するための方法および装置
Document Type and Number:
Japanese Patent JP4034847
Kind Code:
B2
Abstract:
A phase modulator (86, 64, 66, 68) applies sequences of artificial phase shifts in the region of overmodulation between light beams counterpropagating within the sensor coil (40, 42, 44) of a Sagnac interferometer to obtain improved random walk performance. The sequences are composed of phase shifts of +/-a pi /2b and +/-(4b-a) pi /2b where a is an odd integer and b is an integer greater than 1. The waveform for driving the phase modulator is derived from a 2 pi radian mapping plotted so that adjacent driving signal values differ by a pi /2b or -(4b-a) pi /2b in a first angular direction and by -a pi /2b or by (4b-a) pi /2b in the opposite angular direction. Angular transitions about the mapping may be predetermined to generate a deterministic, random, or pseudo-random modulation sequence. In the event that a deterministic sequence is chosen, it is examined for orthogonality properties to assume zero average output bias from crosstalk.
Inventors:
John G. Mark
Daniel A. Tazartes
Amado Cordova
Daniel A. Tazartes
Amado Cordova
Application Number:
JP11166897A
Publication Date:
January 16, 2008
Filing Date:
April 30, 1997
Export Citation:
Assignee:
LITTON SYSTEMS, INCORPORATED
International Classes:
G01C19/72
Domestic Patent References:
| JP5332775A | ||||
| JP3048715A |
Foreign References:
| US5530545 | ||||
| US5123741 | ||||
| US5189488 | ||||
| US5337143 | ||||
| US5184195 |
Attorney, Agent or Firm:
Masao Okabe
Nobuaki Kato
Kazuo
Shinichi Usui
Ikuo Fujino
Takao Ochi
Teruhisa Motomiya
Norimichi Takanashi
Asahi Shinmitsu
Nobuaki Kato
Kazuo
Shinichi Usui
Ikuo Fujino
Takao Ochi
Teruhisa Motomiya
Norimichi Takanashi
Asahi Shinmitsu