Widely Tunable Dual-Wavelength Spacing via Temperature Control in A Single Self-Assembled Nanowire-Well Chip With...

Dual-wavelength single-chip laser sources not only provide multiparameter measurement, but also provide a promising approach for terahertz (THz) signal generation. THz emission relies on the wavelength (or frequency) difference between dual lasing. Wide tunability of the dual-wavelength difference, therefore, enables widely tunable THz signals for more flexible applications. In this paper, we propose a simple approach and mechanism for achieving dual-wavelength emission with a widely tunable center-wavelength spacing on a single chip via unified temperature control. It is based on an InGaAs self-assembled nanowire-quantum well composite structure with laterally periodic nanowire-well and pure-well parts contributing to dual-wavelength emission. Due to distinct stress conditions in the two parts, their emission peaks exhibit markedly different temperature-dependencies. As the temperature increases from 289 K to 321 K, the emission peak of the nanowire-well part only varies from ∼930.6 to ∼931.8 nm (Δ ≈ 1.2 nm), while that of the pure-well part shows a pronounced redshift from ∼963.8 to ∼985.7 nm (Δ ≈ 21.9 nm). Consequently, the dual-wavelength spacing expands from ∼33.2 to ∼53.9 nm (Δ ≈ 20.7 nm), corresponding to a tuning rate of ∼0.65 nm/K. This research holds significant importance for enhancing the dynamic-adaptability and compactness of dual-wavelength semiconductor lasers for advanced applications.