A non-mechanical optical beam steering device includes one or more polarization gratings (PG) coupled to one or more Steerable Electro-Evanescent Optical Refractors (SEEOR). It provides the coarse steering advantage of the PG and also the continuous fine steering advantage of the SEEOR. The result is far less complexity, size, weight, and cost over the alternative non-mechanical beam steering approaches as well as considerably less complexity, size, weight, cost, scanning-time, and mechanical breakdown over the more traditional gimbaled mirrors commonly used.

To eliminate a need for polarization adjustment, to simplify a configuration, and to make a configuration at low cost. Wavelength swept light is provided to a measurement-target optical fiber having an FBG with a chirped grating interval. A polarization multiplexing unit generates polarization multiplexed reference light by multiplexing first reference light and second reference light, which are swept in a wavelength in the same manner as wavelength swept light and have polarizations orthogonal to each other. Polarization multiplexed reference light is input to combine means along with reflected light from measurement-target optical fiber and is made to interfere with reflected light. A signal processing unit performs Fourier transform processing on the digital signal by dividing a time domain into a plurality of periods, and synthesizes the Fourier transform results on a distance axis to obtain a measurement result of orthogonal polarization components of reflected light.

To eliminate a need for polarization adjustment, to simplify a configuration, and to make a configuration at low cost. Wavelength swept light is provided to a measurement-target optical fiber having an FBG with a chirped grating interval. A polarization multiplexing unit generates polarization multiplexed reference light by multiplexing first reference light and second reference light, which are swept in a wavelength in the same manner as wavelength swept light and have polarizations orthogonal to each other. Polarization multiplexed reference light is input to combine means along with reflected light from measurement-target optical fiber and is made to interfere with reflected light. A signal processing unit performs Fourier transform processing on the digital signal by dividing a time domain into a plurality of periods, and synthesizes the Fourier transform results on a distance axis to obtain a measurement result of orthogonal polarization components of reflected light.

The present disclosure relate to a first bidirectional communication device applied to a bidirectional communication system. The first bidirectional communication device comprises a first signal transmitter configured to transmit a first optical signal; a first signal receiver configured to receive a second optical signal from a second bidirectional communication device of the bidirectional communication system; a first beam splitter configured to transmit at least a portion of the first optical signal and reflect at least a portion of the second optical signal; and a first optical lens disposed between the first beam splitter and the second bidirectional communication device. The first optical lens includes a collimating lens and/or a diverging lens.