| 摘要 |
PURPOSE:To obtain an optical fiber gyroscope having a small drift and a high reliability, by constituting an optical fiber branch coupler so that a polished surface of two pieces of optical fibers which have been bent each other is solidified and joined by a transparent solid layer. CONSTITUTION:A light beam from a light source 1 passes through a beam splitter 2 and a polarizer 3 and made incident on one end of an optical fiber 12 of an optical fiber branch coupler 11, a part thereof passes through a ground surface 16, a transparent solid layer 18 and a ground surface 17 and branches to other optical fiber 13, and also, a part is propagated to the other end of the optical fiber 12. In this case, since the transparent solid layer 18 is used, propagation light beams which have been made to branch into two directions are made incident on both ends of an optical fiber loop 5 with stable optical power and extinction ratio. Subsequently, said beams pass through a phase modulator 6, go round to the right and left and propagated, and thereafter, coupled by the branch coupler 11 again and each a photodetector 7, and when a signal obtained from the photodetector 7 is brought to a synchronizing amplification synchronously with an AC voltage for driving the phase modulator 6, a rotation detecting output of a small drift is obtained.
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