Optical fibre amplifier circuit, e.g. for radio and television distribution network - reduces output power to safe level if fibre is broken and detects when fibre is reinstalled

摘要

The circuit (12) is connected to an optical transmitter (S) and an optical receiver (E). It has a fibre reinforcer (17) and a pump source (33) connected to that. The pump source (33) has an associated control circuit (28). This regulates the optical power (NA) from the fibre reinforcer (17) to a first given value. A first alarm signal (S1) is given out from the receiver (E) if no optical signal is present and is supplied to the optical amplifier circuit (12). The control circuit (28) is responsive to this signal (S1) to regulate the optical output power of the fibre reinforcer (17) to a second smaller value. ADVANTAGE - Ensures high transmission reliability and safety.