Design Guidelines for Contactless Integrated Photonic Probes in Dense Photonic Circuits

This paper provides detailed guidelines for the optimal design of contactless integrated photonic probes suitable to track and control the local optical power in photonic circuits. With reference to current technology platforms, this paper provides a guide to extract the electrical parameters of the probe and to highlight their role in defining the achievable resolution. Crucial technological and geometrical choices are discussed, together with layout and interconnection solutions oriented to a highly dense integration of the probes. Finally, the criteria for the optimal coupling of the probes to the most suitable readout electronics providing the maximization of the SNR are presented. With these guidelines in mind, transparent in-line local power monitors featuring -35 dBm sensitivity, 40 dB of dynamic range, broadband response from 1.3 to 1.6 μm, a speed down to tens of microsecond and a minimum size of tens of micrometer can be effectively designed for high performance reconfiguration and closed-loop control of complex photonic circuits.