Beyond Pulse Position Modulation : a Feasibility Study

Sammanfattning: During the thesis work, a feasibility study of the BPPM error-correction protocol is performed. The beyond pulse position modulation (BPPM) protocol was invented at Ericsson AB and describes a modulation encoding using vertically and horizontally polarized single photons for optical transmission and error-correction. The thesis work is a mixture of both experimental laboratory work and theoretical software simulations which are intended to mimic actual optical fiber transmission. One aspect of the project work involves designing the optical communication system which is used to evaluate the probabilities of transmission errors in the form of false detections and losses of light. During the project work, the BPPM protocol is implemented and used for software simulated error generation and correction. With the available laboratory setup used as the point of reference, error-correction using the BPPM protocol is studied using pulses of light containing more than one photon. The results show that the BPPM protocol can be used to recover some of the information that is lost during optical fiber transmission. Factors such as the size of the codewords, the number of photons per pulse and detection efficiency of the utilized single photon detector (SPD) have a significant impact on the success of the transmission.