System, method and apparatus for clockless PPM optical communications

An optical pulse position modulation (PPM) receiver comprising:

• a splitter that splits a received series of delayed optical pulses Q(t) into an original series and a second series, wherein Q(t) represents an input signal U(t) encoded into a series of optical pulses delayed by a delay Δ(t)=bV(t), according to V(t)=U(t)+aV(t−kT), where k is a positive integer and a and b are coefficients;
• 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 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.

A method of performing pulse position modulation (PPM) communications comprising:

• (i) generating equally-spaced optical pulses with a sampling period T;
• (ii) transforming an incoming waveform U(t) into a linear combination V(t) of U(t) and a delayed output V(t−kT) according to a rule V(t)=U(t)+aV(t−kT), where k is a positive integer and a is a coefficient, V(t) is voltage generated by the encoder;
• (iii) delaying the optical pulses in proportion to the voltage V(t), such that A(t)=bV(t), where b is another coefficient and where A(t) is the amount of delay and Q(t) is the delayed optical pulses;
• (iv) transmitting the delayed optical pulses;
• (v) receiving the delayed optical pulses;
• (vi) splitting the delayed optical pulses Q(t) into an original series and a second series;
• (vii) delaying the second series by ckT to produce, Q(t−ckT), wherein c is a positive coefficient;
• (viii) decoding the original series Q(t) and the second series Q(t−ckT) into a signal proportional to the incoming waveform U(t);
• wherein the decoding of the original series and the second series is performed by a semiconductor optical amplifier.