Small-Signal Analysis of All-Si Microring Resonator Photodiode

All-silicon microring resonator photodiodes are attractive for silicon photonics integrated circuits due to their compactness, wavelength division multiplexing ability, and the absence of germanium growth. To analyze and evaluate the performance of the microring photodiode, we derived closed-form expression of the response transfer function with both electrical and optical behavior included, using a small-signal analysis. The thermo-optic nonlinearity resulting from optical loss and ohmic heating was simulated and considered in the model. The predicted response achieved close agreement with the experiment results, which provides an intuitive understanding of device performance. We analytically investigated the responsivity–bandwidth product and demonstrated that the performance is superior when the detuning frequency is zero.

Asymmetric Concentric Microring Resonator Label-Free Biosensors

A study of label-free silicon nitride asymmetric double-microring resonators is presented. The use of highly accurate 3D vector modal techniques permits an extensive exploration of the parameter space defining the architecture of the proposed device in the search for optimal geometries and reaching configurations not addressed in previous studies that had been limited to symmetrical configurations. Asymmetry, on the other hand, permits to access resonances that exploit the radiation-quenching properties of the structure in an optimal way. The analysis presented also includes the effect of absorption in the sensor aqueous cladding that is generally omitted. The results of the numerical survey indicate that the optimized geometries bring about a substantive performance improvement at small microring radii that are impractical for more conventional single-ring geometries due to the high radiation losses. Therefore, lower footprint devices, and a larger scale of integration, can be attained with the proposed structure.

PR36 Towards the Integration of Microring-based Photon-Pair Sources in Silicon Photonics (1640968-Y3)

Our research focused on developing integrated pair sources using silicon photonics technology. This device uses a microring resonator for pair generation. Activities performed this year include measurements of silicon photonic entangled-pair and heralded single photon generation using an integrated photonic microchip that includes the pair generation resonator as well as tunable filters. Summary of a Project Outcomes report of research funded by the U.S. National Science Foundation under Project Number 1640968 (Year 3).

Dual-working mode device based on dual-element photonic crystal-stepped concave waveguide

In this study, a Si3N4 on insulator device used for photonic integrated chips (PICs) is proposed. The dual-working mode device is constructed using a racetrack microring resonator, which is established using a dual-period photonic crystal-stepped concave waveguide (DPCSCW). A novel scheme of dual-working modes is realized, and sensing and filtering are performed simultaneously without interference. The results show that a sensitivity of 558.6 nm/RIU and quality factor of 5795.24 were obtained for the sensor mode. An extinction of 58 dB and bandwidth of up to 335 nm were achieved in the filter mode. The footprint of the entire device is within 20 μm×11 μm, which is ultra-compact and suitable for PICs.

Numerical simulation of optical coupling between a microring resonator and a directly connected straight waveguide

We studied numerically optical coupling of whispering gallery modes of a microring resonator with modes of a radially directed straight waveguide connected to the microring. Optical outcoupling from the resonator through the waveguide was calculated for different widths of the latter. The output was maximized under conditions when the width fits an odd integer number of half-wavelengths of light inside the microring.