Phase-Change-Material Trimmed, Fixed-Wavelength Slow Wave Loop-Terminated Mach-Zehnder Interferometer Sensors for Low-Cost Chem-Bio Sensing Applications

Phase-Change-Material Trimmed, Fixed-Wavelength Slow Wave Loop-Terminated Mach-Zehnder Interferometer Sensors for Low-Cost Chem-Bio Sensing Applications

Presenter(s)

Jianhao Shen

Comments

12:00-12:20, Kennedy Union 311

Description

We experimentally demonstrated a compact slow wave enhanced loop-terminated Mach-Zehnder interferometer (LT-MZI) sensor with phase sensitivity of 277,750 rad/RIU-cm. The sensor employs phase change materials (PCMs) to actively trim interferometer fringes post-fabrication, enabling alignment with fixed-wavelength sources for low-cost on-chip chem-bio sensing. Traditional chip-integrated sensors face challenges due to fabrication-induced wavelength mismatches and dependance on external tunable lasers or alignment-sensitive coupling. Here, antimony selenide (Sb2Se3) PCMs integrated on the LT-MZI reference arm enable non-volatile phase tuning via amorphous-to-crystalline transitions, eliminating the need for energy-intensive, continuously powered thermal tuning elements. The LT-MZI leverages slow light propagation in a 2-dimensional photonic crystal waveguide (2D PCW) structure to amplify phase shifts, achieving enhanced sensitivity. A 2×2 multimode interference (MMI) splitter divides light into reference and sensing arms, which recombine at a second MMI connected to a loop mirror. The LT-MZI’s loop mirror doubles the effective interaction length, further increasing sensitivity compared to standard MZIs. 3D-FDTD simulations confirmed spectral fringe trimming via PCM phase transitions, allowing alignment to fixed-wavelength lasers. This platform addresses fabrication tolerances and enables multiplexed, low-cost sensors. Ongoing work focuses on continuous PCM phase control for precise fringe stabilization. The approach is scalable to diverse interferometric and resonator-based sensors, promising compact, high-sensitivity systems for real-world chem-bio applications.

Publication Date

4-23-2025

Project Designation

Graduate Research

Primary Advisor

Swapnajit Chakravarty

Primary Advisor's Department

Electro-Optics and Photonics

Keywords

Stander Symposium, School of Engineering

Institutional Learning Goals

Scholarship

Phase-Change-Material Trimmed, Fixed-Wavelength Slow Wave Loop-Terminated Mach-Zehnder Interferometer Sensors for Low-Cost Chem-Bio Sensing Applications

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