Patent ID: 7715720

Claim:
An optical device for receiving and demodulating of a pulsed incoming optical signal transmitted through an optical link, comprising: a 90-degrees optical hybrid having a first and a second inputs, a first, a second, a third and a fourth outputs, receiving the pulsed incoming optical signal with a pulse rate P; a pulsed local oscillator having the same pulse rate P with a duration of each optical pulse equal to T 1 , the pulsed local oscillator connected to the 90-degrees optical hybrid via the second input, four balanced photodetectors, connected to the first, the second, the third and the fourth outputs of the 90-degrees optical hybrid, the balanced photodetectors having electrical outputs, a digital signal processing (DSP) unit connected to the electrical outputs of the balanced photodetectors, the DSP unit recovering data from the incoming optical signal, wherein the 90-degrees optical hybrid is adapted to mix a pulse of the local oscillator with the duration T 1 with an incoming optical pulse with a duration T 2 , entering the 90-degrees optical hybrid via the first input, where T 2 is greater than T 1 and thus performing time-domain filtering of the incoming optical signal; and wherein the pulse duration T 1 is within an area of minimal overlapping of adjacent pulses of the incoming optical signal.