Optical fibre receiver

Claim 1

In an optical receiver of the type employing a PIN diode which diode receives a light beam to provide a current through the diode proportional to the light intensity received with said diode in series with a resistive impedance with the junction between the diode and said resistive impedance connected to the gate electrode of a field effect transistor (FET), with the drain electrode of said FET coupled to the emitter electrode of a NPN bipolar transistor and with the source electrode coupled to a point of reference potential, with the collector electrode of said NPN transistor coupled to a point of operating potential and with the base electrode coupled to said point of reference potential via a biasing impedance network, the improvement in combination therewith of apparatus for preventing instability at frequencies of the order of 1 GHz or greater comprising: a series resistor-capacitor network connected across the drain and source electrodes of said FET with said resistor having a value which is low compared to said resistive impedance in series with said diode and wherein said capacitor has a low impedance value at frequencies of the order of 1 GHZ or higher, with said drain electrode coupled to said emitter electrode via a relatively long bond wire which serves as an inductive impedance having a high impedance compared to said capacitor impedance at frequencies of the order of 1 GHz or greater.