Analog link design

In some applications signals originate in analog form and are to be delivered to a remote destination as analog signals. In such cases, it is sometimes more economical or technically feasible to transmit these signals in their original analog form than to convert to a digital format, particularly when the signal bandwidth and/or dynamic range is large enough to stress the capabilities of current digital-to-analog and analog-to-digital converters. This paper discusses analog signal transmission at optical wavelengths in the context of free space links. The technology of optical modulators, amplifiers, and receivers is discussed and an example of an analog crosslink design is given.