公开(公告)号：JPH07306095A

公开(公告)日：1995-11-21

申请号：JP32574394

申请日：1994-12-27

Applicant: ABB RESEARCH LTD

Inventor： MARUKUSU MAIAA

IPC: G01J4/04 ,  G01J4/00 ,  G01N21/21 ,  G02B27/28

Abstract: PURPOSE: To measure a physical/chemical quantity at a low cost without depending on the influence of the temperature by always obtaining a polarization analysis modulation signal from at least one of optical detectors by means of a structure provided with a plurality of polarizing filters. CONSTITUTION: A polarization modulated optical signal L is incident, for example, on a beam splitter ST from a magneto-optical Faraday rotator with the linear polarization direction P. The polarization direction P is provided with a polarization angle α (t) toward a mean position of a polarization face α0. The light signal incident on the beam splitter ST is separated into two partial beams so as to reach the first and the second detectors D1, D2 via the first and the second polarizing filters P1, P2 which cross each other orthogonally. The detectors D1, D2 convert light output signals S1, S2 into a voltage and a digital signal proportional to the voltage on the output side and feed out them to a microprocessor 1 for evaluation. The microprocessor 1 outputs a modulation signal S, which does not depend on the condition of the polarization face α0, so as to feed it to a command device 2.

公开(公告)号：JPH07218272A

公开(公告)日：1995-08-18

申请号：JP32573494

申请日：1994-12-27

Applicant: ABB RESEARCH LTD

Inventor： MARUKUSU MAIAA

IPC: G01C19/72 ,  G01D5/34 ,  G01D5/353 ,  G01N21/21 ,  G01N21/41 ,  G01R15/24

Abstract: PURPOSE: To provide a sensor of optical fiber transmission path type equipped with a modulator, which permits simple performance of signal evaluation. CONSTITUTION: From a light source 1, light is fed to a feed line optical fiber 2. At the first splice spot 3, the light is introduced to the first reference optical fiber 4, and its main axis is turned 45deg. with respect to the feed line optical fiber 2. At the second splice spot, the light reaches the second reference optical fiber 6, and its main axis is turned 90deg. about the first reference optical fiber. At a third splice spot 7, the light is fed to an optical fiber 8 having a low complex refractivity, and this fiber 8 first forms a λ/4 light guide loop 9, and then forms an optical sensor 10. The phase deviation of the light is made controllable statically or dynamically using a phase modulator M coupled with the first reference optical fiber 4.