RF photonic receiver front-end based on crystalline whispering gallery mode resonators

We develop a theoretical model for a direct and a coherent RF photonic receiver front-ends based on optical whispering gallery mode resonators. We show that the coherent receiver has much higher sensitivity and wider dynamic range compared with the direct one. We argue, that the coherent photonic receiver is able to have a spurious free dynamic range in excess of 55 dB and sensitivity in excess of -100 dBm in a 5 MHz reception band. We also discuss recent advances in the practical implementation of the receivers by OEwaves Inc. and compare the experimental results with the theoretical predictions.