| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical demodulator for constituting a delayed interferometer, using space optics, that is used when demodulating an optical signal that has been differential phase shift keyed, thereby increasing the response speed of delay amount control and suppressing optical path shift. <P>SOLUTION: In the optical demodulator, an optical signal that has been differential phase shift keyed is caused to be branched into a plurality of branches, a predetermined delay amount is imparted between the branched optical branches, after which the optical branches are multiplexed into a specific combination, and on the basis of the state of the multiplexed light that has been multiplexed, an electrical signal related to the differential phase shift keying is demodulated. In the optical demodulator, a delay amount imparting means for imparting the delay amount includes a displacement means 12 which is constituted from a plurality of wedge-shaped optical elements 10 and 11 arranged in at least a portion of the optical paths of the optical branches and which, without changing the optical path shifts of the optical branches, displaces at least one of the optical elements. <P>COPYRIGHT: (C)2011,JPO&INPIT |
