RING RESONATOR TYPE SINGLE POLARIZED WAVE FIBER ROTARY SENSOR

摘要

PURPOSE:To obtain a long durable stable and high-precision rotary sensor free from distances, such as vibration and temperature fluctuations, etc., by using as a fiber a single polarized single mode (SPSM) fiber in which the X polarized wave only is transmitted actually. CONSTITUTION:A laser beam 17 (Oscillation frequency of f0) is equally bisected by a half-mirror 18 and each portion is led to an SPSM fiber 23 through a supersonic modulator 19 or 20. Each beam is transformed into a beam transmitted in an SPSM fiber coil 25 in the clockwise or counter-clockwise direction by a photo-coupler 24. By selecting a core radius (a) of an optical fiber or specific refraction coefficient difference DELTA, the SPSM fiber transmitting only x polarized is obtained. As a result of using this kind of the SPSM fiber in a ring resonator type fiber sensor, a problem of change at random at a resonance phase caused by the conventional mode couplings can be eliminated.