| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a demodulator easily controlling a phase in a light transmission system using differential phase modulation. <P>SOLUTION: The modulator (50) is provided with: a branching means (51), which branches a differential phase modulation light signal into a first branch light (62) and a second branch light (63) to emit first branch light into a first optical path (A) and emit second branch light into a second optical path (B); a first medium (53) arranged on the first optical path; a second medium (55) arranged on the second optical path and provided with a refractive index different from that of the first medium so that the second branch light is delayed with respect to the first branch light having passed the first medium by 1 symbol; and a multiplexing means (54), which multiplexes the first branch light having passed the first medium with the second branch light having passed the second medium. <P>COPYRIGHT: (C)2010,JPO&INPIT |
