An optical amplifying device.

摘要

A device for amplifying an input optical signal includes an optical amplifier having a gain control region (14) in which the input optical signal is amplified, a first detecting region (13) for detecting the input optical signal, and a second detecting region (15) for detecting an amplified optical signal. The gain of the optical amplifier is controlled by a gain control signal from a signal source (17). A controller (18), responsive to detecting signals (S1,S2) from the first and second detecting regions (13,15), produces a source control signal which is supplied to control the signal source (17).