摘要 |
In a of modulating a feedback signal in an optical amplifier, employing a laser diode LD, which can directly amplify an optical signal, the amplified optical signal is modulated by the feedback signal SV which is controlled in such a way as to compensate for the saturation characteristics of the laser diode LD to correctly modulate the feedback signal even if the laser diode is nearly saturated due to aging or fluctuations in temperature. |