| 摘要 |
PURPOSE:To obtain a compensator of a small-sized, simple and inexpensive optical transmission system, by providing a compensating system constituting of a light emitting element, photodetector and variable optical attenuator VLA having the same characteristics as the optical transmission system. CONSTITUTION:A signal received via an optical transmission system consisting of a light emitting element LED1, optical fiber OF1 and photodetector PD1 is outputted via an amplifier OP1 and transistor TR1, and applied to a load R1. A part of the output signal is fed back to the OP1 via a compensator consisting of an element LED2, PD2 and VLA having the same characteristics as the said LED1 and the PD1. Thus, the temperature of said optical transmission system and the nonlinear aging change of the LED1 and PD1 can be compensated. The VLA is formed by vapor-depositing a metal so that the film thickness can continuously be changed on a transmittable disc and along its circumferential direction. |
