Optical fibre amplifier noise figure measurement

摘要

The method employs a distributed feedback laser diode (1) producing a continuous beam (A) in the 1.55- mu m waveband for chopping (2) into a pulsed signal (C) with 1- mu s period and 50% duty ratio. The Er<+3>-doped fibre amplifier (4) outputs an amplified signal (D) with delay. The output is modulated with a pulse (G) from a control unit (3) and converted (6) by a photoelectric detector (6) into a power signal (PO) which is fed back to the control unit. The chopping and modulating pulses (B,G) are adjusted in phase to maintain a maximum photoelectric power level for measurement.