Optical communications offer many advantages over radio frequency communications. Lasers are very efficient in establishing a communication link; however, they have a major drawback, which is background radiation, because background radiation limits the efficiency of optical communications. In this thesis, we analyze inexpensive lasers and their vulnerabilities to background radiation. We present a new way of calculating background radiation by using measured data and Planck’s Law. Next, we consider how to maximize the bit rate of a communication link for inexpensive lasers. We also investigate several modulation types for optical communication. We present M-ary pulse-position modulation (MPPM) and a novel method of direct detection. Next, we compare MPPM with on-off keying (OOK) in terms of power requirements. It is shown that MPPM is much more power efficient than OOK modulation; 32-PPM requires 7.6 dB less power than OOK to achieve the same probability of bit error. We use Simulink to model MPPM performance, and we compare analytical results with simulated results.

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Lieutenant Junior Grade, Turkish Navy