A CMOS-compatible heterogeneous interferometer for chip-scale temperature sensing

David A Payne, Jonathan C F Matthews*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

3 Citations (Scopus)
79 Downloads (Pure)

Abstract

We report a photonic temperature sensor with enhanced performance in both broad- and narrow-bandwidth optical measurements. The device consists of a heterogeneously in- tegrated Mach-Zehnder interferometer with arms composed of silicon and silicon nitride waveguides whose thermo-optic coefficients differ by an order of magnitude. The waveguides are fabricated in distinct layers of a monolithic device and guide light in a single transverse-electric mode. The resulting small bend radii enable compact sensing of temperatures local to integrated photonic components with a device footprint of 580 × 410 μm2. Furthermore, the dual layers of the sensor enable overlaying of the spiral arms of the in- terferometer over each other or other photonic circuit components. We measure a sensitivity of 324 pm/K, an over threefold enhancement compared to the measurement of an asymmetric Mach-Zehnder constructed of silicon waveguides on the same device. We additionally define a useful figure of merit for the side-of-fringe measurement regime which uses direct detection of a narrow linewidth laser and show that the reported device is also competitive on this metric.
Original languageEnglish
Article number261104
Number of pages8
JournalApplied Physics Letters
Volume121
Issue number26
DOIs
Publication statusPublished - 26 Dec 2022

Research Groups and Themes

  • QETLabs

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