System implementation of coherent analog optical links

Coherent detection in analog optical links offers several advantages, including increased linearity, heterodyne frequency conversion capability, and reduced link noise figure. Implementing a coherent link in a microwave communications system requires understanding and mitigation of coherence-related noise. We describe an analog optical link using coherent detection and amplitude modulation to achieve high dynamic range, high link gain, and low noise figure. We then address the dominant performance-limiting parameters and discuss several approaches to overcome these limitations.