| 摘要 |
<p>A light projecting/detecting portion for projecting a laser light onto a reflector of a rotating body and receiving its reflected light is made smaller. A light sending/receiving device (21) comprises an incident light receiving fiber (25a, 25b) for guiding both an incident light and a reflected light, and a light projecting/detecting portion (11a, 11b). Further, it comprises a polarization-preserving fiber circulator (24a, 24b) by which a reflected light is received from the same optical path through which a laser light from a laser light output device (20) is outputted via a branch connector (23). Polarization-preserving fiber circulator (24a, 24b) polarizes the laser light, outputs it, receives the reflected light through the same optical path through which the laser light is outputted, separates the reflected light from the laser light from the laser output device (20), and outputs it to a signal processing device (22) for determining a torque.</p> |
