OPTICAL FIBER SAGNAC INTERFEROMETER FOR MEASURING ROTATIONAL SPEED

摘要

PURPOSE: To stabilize the wavelength of a light source by using a signal decoded with the second synchronous decoder for changing the temperature and feed current of the light source. ;CONSTITUTION: Two beams emitted from a light source L, polarized with a polarizer P and generated through a beam splitter ST2 are incident on a fiber coil FS. An interference pattern occurring due to the subsequent recoupling of the beams acts on a detection device PD1 after passing the polarizer P. Also, the two beams are modulated into signals PMS via a phase modulator PM. The signal component AT1 of the signals PMS are ramp signals, and the signal component AT2 is a sum of components AT1 and AT22. Furthermore, the output signals of the device PD2 are decoded with the first synchronous decoder SYNCD1. In this case, a part of the beams downstream of the splitter ST2, and the modulator PM acts on the device PD1 after reflection, recoupling and travel through the polarizer P, and the output signals of the device PD1 are decoded with the second synchronous decoder SYNCD2. The temperature and feed current of the light source L are changed by utilizing the decoded signals S2 for changing and stabilizing the wavelength of the light source L.;COPYRIGHT: (C)1995,JPO