The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 23, 1993
Filed:
Feb. 01, 1993
Shigeru Oho, Hitachi-shi, Ibaraki 316, JP;
Hisao Sonobe, Katsuta-shi, Ibaraki 312, JP;
Junichi Makino, Katsuta-shi, Ibaraki 312, JP;
Hiroshi Kajioka, Tsuchiura-shi, Ibaraki 300, JP;
Tatsuya Kumagai, Hitachi-shi, Ibaraki 319-14, JP;
Other;
Abstract
An interference sensor passes radiation from a source and a polariser to a loop of optical fiber so that radiation beams circulate in opposite directions around the loop and interfere. The loop contains an optical phase modulator which imposes an optical modulator on the radiation beams circulating on the loop. A converter detects the interfering and modulated beams and generates an interference signal which is then processed by an analyser. The interference in the loop is dependent on rotation of the loop and therefore analysis of the interference signal permits that rotation to be measured. In the present invention, the interference signal is (i) sampled at a frequency different from that of the optical modulation, or (ii) electronically modulated in the analyser at a frequency different from that of the optical modulation, or (iii) optically modulated in the loop at a second optical modulation frequency. The analysis in the analyser may be in the frequency domain (i.e. consideration being given to the frequency of the interference signal) or in the time domain (i.e. independent of frequency).