Mitsubishi Electric Corporation has developed an optical receiver for use in laser communication terminals (LCTs). The prototype combines laser beams with a function to detect the direction of received beams in the 1.5-μm band, a general-purpose band used for terrestrial optical fiber communications and other applications.
Mitsubishi Electric said its optical receiver integrates functions to detect both four phase changes of laser light and beam direction. The result is a downsized optical receiver that enables space optical communication with 10 times the speed, capacity and distance of radio-wave communication. Since the wavelength is much shorter, smaller antennas can be used in compact communication units.
A newly developed optical circuit for coherent space optical communication detects four phase changes (0, 90, 180, and 270 degrees) in contrast to conventional two-phase (0 and 180 degrees) detection. As a result, communication capacity and speed are double those of two-phase optical communication schemes in the same bandwidth and some 10 times those of radio-wave communication systems.
