US Patent 7526206 Laser communications crosslink system

A laser communication crosslink system employs an nth order sigma delta modulator with a laser transmitter for communicating an analog input signal in binary form as a pulse width modulated signal, and employs a digital filter with a receiver for providing a digital output signal representing the value of the analog input signal. The pulse width modulated laser signal is communicated between the transmitter and receiver over a laser crosslink that may be fiber optic. The direct modulation using the sigma delta modulator with the transmitter and using the digital filter with the receiver reduces system complexity and power consumption.