WDM Ring-Resonator Sensor Array with Thermal Reference

This simulator models a wavelength-division-multiplexed silicon-photonic biosensor chip: five ring resonators, each parked at its own resonance wavelength, are functionalized to bind an analyte and sit beneath a microfluidic channel, while a sixth ring is fluid-isolated and serves purely as a thermal reference. A Langmuir binding isotherm converts analyte concentration and receptor affinity (K_d) into fractional surface coverage, which shifts every sensing dip in the transmission spectrum; a shared thermo-optic coefficient shifts every ring, sensing and reference alike, whenever the chip's temperature drifts. Toggling the differential-reference compensation shows, live, how subtracting the reference ring's shift from a sensing ring's shift cancels the thermal term and recovers the true analyte-only signal — the same common-mode-rejection trick real photonic biosensor chips use to stay accurate outside a temperature-controlled lab.