Investigation of suitable modulation techniques for underwater wireless optical communication

For an underwater wireless optical communication system, we consider the use of different intensity modulation techniques, and compare their performance by taking realistic system parameters into account. In particular, we contrast the performances of on-off keying, pulse position modulation, pulse width modulation, and digital pulse interval modulation, when a PIN or an avalanche photodiode is used at the receiver. We discuss the suitability of these modulation techniques to the underwater optical channel by considering the implementation issues.