| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical reception panel excellent in long term reliability, and capable of obtaining ideal reception sensitivity and freely receiving a signal light with an optional wavelength. SOLUTION: A signal light is amplified by an optical fiber amplifier 31 and band-limited by a motor-driven wavelength variable optical filter 32, part is branched by an optical branching element 33, photoelectric-converted by a photo diode 35 and an information electric signal is reproduced via an equalization amplifier circuit 36 and an identification circuit 37. The motor-driven wavelength variable optical filter 32 has a rotor actuator having a magnet rotor and a coil and an optical filter film element is fixed to the actuator and the actuator is driven. A superimposed signal among a sweep signal of a transmission center wavelength of the motor-driven wavelength, a DC component for tracking control and an AC component for detecting an error signal is outputted from a control circuit 40. At the time of starting the optical reception panel, sweeping is conducted till a prescribed value is obtained at a signal level detection circuit 39 and tracking is controlled to maximize a transmission optical power. |
