Low noise photon coupled circuit

摘要

PCT No. PCT/AU95/00599 Sec. 371 Date Mar. 14, 1997 Sec. 102(e) Date Mar. 14, 1997 PCT Filed Sep. 14, 1995 PCT Pub. No. WO96/08857 PCT Pub. Date Mar. 21, 1996A photon coupled circuit comprises a high quantum efficiency semiconductor light emitter (TDA) coupled with low photon losses to a high quantum efficiency semiconductor light detector (OLD). Bias current is provided to both the light detector (OLD) and light emitter (TDA). The light output of the light emitter (TDA) is modulated by the signal current flowing therein and the current flowing (io) in the detector (OLD) is modulated by the light received from the light emitter (TDA). The quantum transfer efficiency or open loop current gain is greater than 0.5 and a portion of the AC current flowing in the light detector (OLD) is applied as feedback to reinforce or oppose the current flowing in the light emitter (TDA).