Patent ID: 8526829

Claim:
A pulse position modulation (PPM) optical communications system comprising: a transmitter comprising: an optical clock generator generating a series of periodic optical pulses of period T; an encoder that encodes an input signal U(t) into a series of delayed optical pulses Q(t) by delaying the periodic optical pulses by a delay Δ(t)=bV(t) according to V(t)=U(t)+aV(t−kT), where k is a positive integer, a and b are coefficients; a receiver comprising: a splitter that receives the series of delayed optical pulses Q(t) then splits the received series of delayed optical pulses Q(t) into an original series and a second series; a delay module that delays the second series by ckT to produce, Q(t−ckT), wherein c is a positive coefficient; an optical pulse decoder receiving the Q(t) and Q(t−ckT); and a photodetector receiving an output of the optical pulse decoder; wherein the optical pulse decoder comprises a semiconductor optical amplifier.