ThermoPix: A High-Spatial-Resolution ElectronicPhotonic Temperature Sensor Array With Microsecond Row Readout

2026-06-03

AI Summary

This work addresses the demand for on-chip temperature sensing with high spatial resolution, low power consumption, and operation under ambient conditions by proposing a CMOS-compatible electronic–photonic hybrid architecture. The design uniquely integrates a valley photonic crystal Mach–Zehnder interferometer (VPCMZI) with a phase-change-material-based CMOS timing readout circuit, converting temperature-induced wavelength shifts into time-domain signals for efficient readout. Bidirectional or non-uniform splitting schemes are introduced to enable scalable optical power distribution. Simulation results demonstrate a temperature sensitivity of 3.15 ns/K, a row readout time of only 2 μs, a per-pixel energy-delay product as low as 0.152 fJ, an optical power requirement of merely 150 nW, and a minimum pixel pitch of 23.26 μm.

Abstract

This paper presents ThermoPix, a CMOS-compatible electronic-photonic architecture for high-spatial-resolution temperature sensing. The proposed system converts temperature-induced wavelength shifts in a photonic interferometric sensor into timing information that can be processed by CMOS circuitry. We use a valley photonic crystal Mach-Zehnder interferometer (VPCMZI) as the sensing element, whose temperature-dependent spectral response is detected using an integrated waveguide photodetector and translated into a time-varying photocurrent. A CMOS readout circuit employing a phase-transition-material device performs threshold detection and generates a timing signal corresponding to the temperature-dependent crossing event. Circuit-level simulations demonstrate a temperature sensitivity of 3.15 ns/K, a row readout time of 2 us, and a sensing power-delay product (PDP) of 0.152 fJ. The required optical power per photonic cell is 150 nW, enabling energy-efficient array operation without requiring cooling or special environmental arrangements. We also present alternative photonic layer architectures for optical power distribution across the array. In one approach, we use different tap ratios along the row, while the other uses identical tap ratios with bidirectional excitation. The resulting average photonic cell pitches are 23.26 um and 38.52 um, respectively. The proposed ThermoPix architecture therefore provides a scalable platform for integrated temperature sensing arrays that combine photonic sensing elements with CMOS-compatible timing-based readout.

Problem

• temperature sensing
• high spatial resolution
• CMOS-compatible
• photonic sensor array
• microsecond readout

Innovation

• electronic-photonic integration
• timing-based readout
• photonic crystal interferometer
• CMOS-compatible sensor
• ultra-low-power temperature sensing