Optical resonator-based ultrasound detection plays a significant role in the modern ultrasonography. It consists of two steps including the optical readout of the acoustic wave signal and the electrical demodulation of the acoustic response. In this paper, we conduct innovative researches on both of them for improved performance. High quality-factor (Q-factor) chalcogenide glass (ChG) microdisk and microring resonators as optical readout configurations are designed and fabricated. High-precision digital optical frequency comb (DOFC) technique is proposed to monitor the minor resonance frequency shift. The sensitivity up to 2.86 dB/Pa and noise equivalent pressure (NEP) down to 4 Pa are obtained under the 40 KHz ultrasound vibration using a 100-μm radius ${\rm{Ge_{11.5} A_{s24}Se_{64.5}}}$ microdisk resonator with the Q-factor of ${11.5\times10^{6}}$ . As a proof-of-concept, three cascaded ${\rm{SiN_{x}}}$ microring resonators-based ultrasound detector is fabricated and characterized to further validate the versatility of DOFC in the arrayed microcavities. Successful realization of the threedimensional ultrasound detection paves the way to the development of high-performance photoacoustic imaging.

We present the design, preparation and performance optimization of strip waveguide in chalcogenide glass (ChG) for broadband supercontinuum (SC) generation. Ternary Ge-Sb-S systems possess large band-gap, high refractive index and strong laser damage resistance. The characterization of strip waveguide in Ge-Sb-S glass for SC source generation with 1300 nm bandwidth is experimentally demonstrated. Sensing capability of the device is validated for optical absorption of β-phenylethylamine solutions near 1551 nm in various concentrations, revealing the repeatability and consistency of the generated SC spectrum in test. The advantages of high specificity detection scheme, scalable integration and ease of miniaturization might make the device a promising platform for biochemical monitoring.

On-chip waveguide-integrated suspended microcavity resonator as a good sensing element is constantly pursued combining with the advantages of an optical material to enhance device performance. In this work, low-loss waveguide-integrated suspended Ge $_11.5$ As $_24$ Se $_64.5$ microdisk resonators have been successfully demonstrated using an optimized etching recipe. The realization of propagation loss down to 0.48 dB/cm verifies the low-loss characteristic of chalcogenide glass rectangular waveguide. An optical loaded quality factor of 1.1×10 $^6$ for the no suspended microdisk resonator, approaching to the highest figure (1.2×10 $^6$ ) so far reported in planar chalcogenide optical devices, is obtained experimentally to reveal the natural evolution of high quality chalcogenide glass membrane thermally evaporated into an oxidized silicon wafer during the engineering of shallow suspension configuration. By comparing with the scattering loss of mode in no suspended case, the contributions of bottom roughness scattering to the optical losses increase exceeding 50% in the shallowly suspended counterparts. The development of waveguide-integrated suspended chalcogenide glass microdisk resonator is expected to enhance the interactional abilities in applications of the gas sensing and ultrasound detection.