Sulfur-rich chalcogenide claddings for athermal and high-Q silicon microring resonators

Abstract

Heterogeneous integration of materials with a negative thermo-optic coefficient is a simple and efficient way to compensate the strong detrimental thermal dependence of silicon-on-insulator devices. Yet, the list of materials that are both amenable for photonics fabrication and exhibit a negative TOC is very short and often requires sacrificing loss performance. In this work, we demonstrate that As20S80 chalcogenide glass thin-films can be used to compensate silicon thermal effects in microring resonators while retaining excellent loss figures. We present an experimental characterization of the glass thin-film and of fabricated hybrid microring resonators at telecommunication wavelengths. Nearly athermal operation is demonstrated for the TM polarization with an absolute minimum measured resonance shift of 5.25 pm K−1, corresponding to a waveguide effective index thermal dependence of 4.28×10-6 RIU/K. We show that the thermal dependence can be controlled by changing the cladding thickness and a negative thermal dependence is obtained for the TM polarization. All configurations exhibit unprecedented low loss figures with a maximum measured intrinsic quality factor exceeding 3.9 × 105, corresponding to waveguide propagation loss of 1.37 dB cm−1. A value of−4.75(75)×10-5 RIU/K is measured for the thermo-optic coefficient of As20S80 thin-films.

Process Variation-Aware Compact Model of Strip Waveguides for Photonic Circuit Simulation

“…where δ represents a small perturbation in the values, Γ n is the confinement of the mode within material n and ∂n n /∂T is the thermo-optic coefficient of material n [42]. Though this equation is widely used [43]- [45] and may be accurate in certain scenarios, to the authors' knowledge it has never been demonstrated to be a generally accurate approximation. We therefore start from first principles and consider a general perturbation of the wave equation [46]:…”

Athermal Chalcogenide Microresonator Cladded With Polymer

“…Γ air can be ignored considering the small fraction of mode confinement in air. The confinement factor (Γ) in different materials is defined as [32], [33]:…”

Compact Mid‐Infrared Chalcogenide Glass Photonic Devices Based on Robust‐Inverse Design

“…Particularly, ChGs have been regarded as promising materials for mid-IR integrated photonics owing to their excellent optical transparency (0.5-25.0 μm), [4] extremely high nonlinearity ((2-20) × 10 −18 m 2 W −1 ), [11] and substrate-blind integration capability. [8] However, low-loss waveguides and microcavities based on ChGs can be directly fabricated on silicon or mid-IR transparent material substrates [12][13][14] for mid-IR sensing [1,15] and supercontinuum generation applications. [9,[16][17][18] On the other hand, ChGs can also be integrated with novel optoelectronic materials such as 2D materials or III-V materi-als to develop active devices, including mid-IR modulators, [8,19] detectors, [8] and laser sources.…”