To recognize a plurality of bits of high-speed optical signals in a lump with a simple construction and further to improve discrimination power of signals recognized in a lump.
Serial signal light emitted from an optical fiber 12 and converted into parallel signal light 26 by a lens 14 is made incident on an optical switch thin film 18 via a mask member 16 on which a plurality of mask patterns with transmission parts and non-transmission parts, transmitting or cutting off one bit of the signal light, disposed thereon so as to form respectively different patterns are formed. When control light 25 is made incident on the optical switch thin film 18, the parallel signal light beams 26 having passed through the respective mask patterns are transmitted and converted into parallel signals and each of them is detected by an optical detector out of an optical detector array 24 corresponding to the mask pattern. Here, detection sensitivity of each of the optical detectors is adjusted by interposing a filter 40 of which the transmittance varies corresponding to the number of the transmission parts of each mask pattern (the transmission bit number) and the bit pattern of the signal light is identified by comparing the respective detected light intensity values with each other.
FURUKI MAKOTO
TATSUURA SATOSHI
SATO YASUSATO
DEN TAMINORI
MITSU HIROYUKI
Kato Kazunori
Katsuichi Nishimoto
Hiroshi Fukuda