OPTICAL FIBER TYPE SENSOR

摘要

PURPOSE:To shorten the length of an optical fiber to half and to decrease the number of connecting devices by propagating light in an optical fiber and an optical fiber for delay forward and backward through one polarization beam splitter. CONSTITUTION:Intensity-modulated carrier light outputted by a light emission part 1 enters the polarization beam splitter 11 through the beam splitter 31 and optical fiber 2 and one of two branched intensity-modulated carrier light beams is transmitted through a 1/8-wavelength plate 32 and a Pockels element 33 and reflected totally by a reflecting mirror 34 to enter a polarization beam splitter 11 as light (a) having a double side bands (DSB). The other intensity- modulated light is guided to one end of the optical fiber 35 for delay and reflected totally by a reflecting mirror 36 to enter the polarization beam splitter 11 as intensity-modulated carrier light (b) which is 3/4pi delayed. Then the light beams (a) and (b) entering the polarization beam splitter 11 are put together into phase-modulated light (q), which is guided to a photodetection part 6 through the optical fiber 2 and beam splitter 31.