| 摘要 |
PROBLEM TO BE SOLVED: To achieve an optical demultiplex circuit by which a high speed optical signal train useful for optical communication and optical information processing can be demultiplexed with simple constitution. SOLUTION: A semiconductor laser element 1 is operated in mode-locking by making a forward current flow through a gain region 101 and impressing a reverse bias on a saturable absorption region 102. With this semiconductor laser element 1, absorption is modulated in the saturable absorption region 102, and a mode-locking frequency is pulled in a frequency f/m which is 1/m times (m = integer) of a clock frequency of the optical signal pulse train. At the same time, a photo-electric current pulse of a frequency f/m is generated in the saturable absorption region 102. This photo-electric current is converted into voltage by a current-voltage conversion amplifier 80, and then, the voltage is applied on an electric field absorption type optical modulator 2. |
