Widely tunable short-wave mid-infrared hybrid lasers enabled by a single ultra-compact silicon microring resonator

Abstract

Chip-scale widely tunable laser sources operating in the short-wave mid-infrared range (2–2.5 μm) have garnered significant interest for applications such as spectroscopic sensing, industrial gas detection, and biomarker measurement. However, conventional chip-scale designs rely on bulky Vernier-effect architectures with multiple filters, introducing complexity, large footprints, and intricate control systems that hinder scalability and practical deployment. In this work, we demonstrate widely tunable GaSb-silicon hybrid lasers that employ a single ultra-compact silicon microring resonator with a 5 μm radius as the wavelength-selective element. The microring exhibits a tuning range exceeding 34 nm in the 2 μm waveband. By integrating three different gain chips, we achieve hybrid lasers with wavelength tuning ranges of 22, 22, and 17 nm centered at 1.95, 2.11, and 2.37 μm, respectively. The lasers demonstrate a side-mode suppression ratio greater than 50 dB, ensuring high spectral purity. This ultra-compact design, combined with a straightforward tuning mechanism, makes the proposed laser highly suitable for practical applications in spectroscopy and detection.