Integration of chalcogenide waveguides in silicon photonics can mitigate the prohibitive nonlinear losses of silicon while leveraging the mature complementary metal–oxide–semiconductor (CMOS)-compatible nanophotonic fabrication process. In this work, we demonstrate, for the first time, to the best of our knowledge, a method of integrating high- Q chalcogenides microring resonators onto the silicon photonics platform without post-process etching. The method uses micro-trench filling and a novel thermal dewetting technique to form low-loss chalcogenide strip waveguides. The microrings are integrated directly inside silicon photonic circuits through evanescent coupling, providing an uncomplicated hybrid integration scheme without the need to modify the existing photonics foundry process. The microrings show a high quality factor exceeding 6 × 10 5 near 1550 nm and propagation losses below 0.7 dB/cm, indicating a promising solution for low-cost, compact nonlinear photonic devices with applications in various fields such as telecommunications and spectroscopy.

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.

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Integrated photonics is of growing interest but relies on complex fabrication methods that have yet to match optical losses of bulkier platforms like optical fibers or whispering gallery mode resonators. Spontaneous matter reorganization phenomenon (e.g. dewetting) in thin-films provides a way for self-assembled structures with atomic scale surface rugosity, potentially alleviating the problems of roughness scattering loss and fabrication complexity. In this article, we study solid-state dewetting in chalcogenide glass thin-films and demonstrate its applicability to the fabrication of high-quality integrated photonics components. Optimal dewetting parameters are derived from a comprehensive experimental study of thin-film properties under high temperature rapid annealing. Atomic scale surface roughness are obtained using dewetting, with RMS values as low as R q  = 0.189 nm. Several integrated photonics components are fabricated using the method and characterized. We show that the use of pre-patterned templates leads to organized, reproducible patterns with large-scale uniformity and demonstrate the record high quality-factor of 4.7 × 106 in compact (R = 50 µm) microdisks, corresponding to 0.08 dB⋅cm−1 waveguide propagation loss. The integrated devices are directly fabricated on standard silicon-on-insulator dice using the micro-trench filling technique and coupled to silicon waveguides, making them readily deployable with existing silicon devices and systems.

This paper reports the formation of laser-induced periodic surface structures (LIPSS) observed on the ablated surface of bulk As2S3 chalcogenide glasses produced after irradiation by a focused beam of femtosecond Ti:sapphire (fs)-laser (1 kHz, 100 fs, 800 nm). By controlling the irradiation condition of fs-laser, high spatial frequency LIPSS (HSFL) ripples parallel to polarisation of the incident light are formed. Nanovoids with an average diameter of ~300 nm and depth of 200 nm also appear between the ripples. Furthermore, we show a transition from the HSFL features toward the formation of low-spatial-frequency LIPSS (LSFL) with an intermediated complex structure of ripples, which are oriented simultaneously parallel and perpendicular to the polarisation of the incident light that we call cross-superposed LIPSSs.