Dual waveguide coupled microring resonator sensor based on intensity detection

This paper systematically analyzes the device sensitivity of a dual waveguide coupled microring resonator sensor based on intensity detection. The relation between the device sensitivity and transmission coefficient, coupling coefficient, and operating wavelength has been derived and simulated, showing that the sensitivity can be enhanced by proper adjustment of the coupling coefficient and the operating wavelength. The explicit expressions of optimal self coupling coefficient, and operating wavelength are derived, serving as the basis for design and optimization. Simulations performed based on the experimental data lead to much smaller detection limit in terms of the effective index change delta n(eff). With a 30-dB signal-to-noise ratio measurement system, the optimized delta n(eff) reaches similar to 10(-7) for both structures in this study, two orders of magnitude smaller than the previous results. In conjunction with the analysis of the waveguide sensitivity, design guidelines are generalized and presented.