SEMICONDUCTOR OPTICAL AMPLIFIER USED AS AN IN-LINE DETECTOR WITH THE SIGNAL DC-COMPONENT CONSERVATION

We present in this paper a de-coupled in-line optical detector based o n a multisection semiconductor optical amplifier (SOA), The key princi ple is to use a voltage reference correlated with the bias voltage lev el by the way of a two-section or a three-section SOA. So, by means of the differential detection, the signal de-component is kept with redu ced sensitivity to temperature and bias current fluctuations. Experime ntal and theoretical results are presented when a two-section SOA is u sed and performance predictions when a three-section is employed, The obtained responsivity is -63 V/W at 40 mA and over -110 V/W at 50 mA w hen the input optical power, measured within the fiber, is -13 dBm, Wh en the SOA is biased at 40 mA, the detection bandwidth is over 1 GHz w hen the input optical power is -4 dBm.