Optical signal detecting circuit and an optical receiver

Optical signal detecting circuit (10) comprises an optical signal amplifier circuit an electrical signal (Tout) and the differential amplifier outputs a differential output signal (Aout) corresponding to the pulse train of (Pin) (11), the differential output by comparing the voltage value of the voltage value and the negative-phase signal of the positive phase signal of the signal (Aout), and a comparator (12) for outputting a pulse-like comparison output signal (Cout) corresponding to the comparison result. Amplifier circuit (11) comprises a current summing circuit (11E), the positive phase signal of the amplified output signal (Aout) (Aout +) and reverse phase signal (AOUT-) DC load current to produce respective external adjustment voltage source is adjusted according to the adjustment voltage value from (Vadj), to adjust the DC bias of the positive phase signal (Aout +) of the DC bias and the reverse phase signal (AOUT-).