Incoherent Ultrafast OCDMA Receiver Design With 2 ps All-Optical Time Gate to Suppress Multiple-Access Interference

We have investigated both theoretically and experimentally the elimination of multiple-access interference (MAI) in an incoherent optical code-division multiple access (OCDMA) system by using a novel incoherent dual code OCDMA receiver incorporating an ultrafast all-optical time gate (AOTG). A theoretical analysis was performed based on (3,11) frequency-hopping time-spreading OCDMA codes with a chip size of 73 ps. To experimentally demonstrate the elimination of MAI, the novel receiver comprising an ultrafast 2 ps-AOTG was developed and tested in a representative OCDMA network testbed. Experimental measurements confirmed by simulations show error-free [bit error rate (BER) < 10^-2] operation for up to four users. Simulations also predict that receivers equipped with 2 ps-AOTG will more than triple the number of simultaneous users without degrading BER.