| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical transmission system for flexibly dealing with the change in communication capacity and dealing with various communication forms, as well by superimposing modulated light corresponding to the electric signal of a frequency which are allocated to each optical transmitter/receiver onto bias light. SOLUTION: At an optical transmitter/receiver 10, the electric signals of frequencies f1-f4 corresponding to respective optical transmittance/receivers from 11-1 to 11-4 are synthesized by a synthesizer 24 and inputted to a laser diode(LD) drive circuit 21 of an optical transmitter 20. In this case, a signal mixing the superimposed electric signals of frequencies f1-f4 with a DC current for biasing an LD 32 is converted into an optical signal, mixing the modulated light and the bias light. Further, this beam is amplified by an optical amplifier 23, split by three photocouplers 41-43 and emitted to respective optical transmission lines from 12-1 to 12-4. Moreover, light reflection at its open terminal is terminated by terminators 44 and 45. Afterwards, the signal is transmitted to the respective optical transmitter/receivers from 11-1 to 11-4. Thus, the optical transmission system, utilizing light reflection for dealing with the change in communication capacity and the various communication forms as well, can be provided. |
