| 摘要 |
PROBLEM TO BE SOLVED: To obtain a time multiplexed optical circuit of a small loss and a small size by inserting a TM/TE mode conversion circuit into at least one route among routes from a branch circuit to a wave synthesizing circuit so as to constitute a time delay circuit. SOLUTION: For example, a light input pulse train 31 is incident by a TM mode, divided into first and second routes 18 and 19 at the Y branching part of a Y branch circuit 13 and the light pulse trains are modulated by the modulation part of each. A pulse train 33 is transformed from a TM mode to a TE mode at the first route 18. A pulse train 34 is wave-synthesized by keeping the TM mode at the second route 19 on the other hand. At each mode propagating a delay circuit 15, time delay at the time of emitting varies depending on the propagating constant difference between them. At the time of properly setting the length of the waveguide of the circuit 15 between the pulse trains including a time delay difference at a Y branch wave synthesizing circuit 16 so as to overlap the other pulse train, the light pulse train 35 (TM&TE coexisting) of a light output 20 provided with a double transmission rate is made. |
