Signal processing in analog optical links

The quest for ever-greater situational awareness creates a need for continuous improvement in signal processing technology. Avionic platforms present a particularly challenging host platform in terms of size, weight, and power (SWaP), with RF signals a major area of interest. Decades of unbroken exponential progress in underlying microelectronics technology combined with the flexibility of programmable function have made digital signal processing (DSP) the signal processing method of choice, yet RF signal processing continues to exhibit significant analog aspects. Analog signal processing (ASP) is used only when a system constraint compels it. One such constraint arises from the fact that signals are generally analog to start with, compelling an analog to digital conversion (ADC) step that has many analog aspects. A second case are classes of signal processing problems for which the necessary ADC technology is not available, for which ASP must be at least partially employed. Finally, the DSP task itself may be too costly relative to an ASP alternative. We consider here opportunities for optical technology to impact these constraints and discuss their common challenge, the analog optical link.