Dual-wavelength distributed feedback laser based on waveguide Bragg grating microcavities

We demonstrate a new, to the best of our knowledge, dual-wavelength distributed feedback laser platform based on a waveguide Bragg grating microcavity incorporating uniform sidewall gratings. This is the first single-section, single-contact device achieving simultaneous dual-wavelength operation at 1.55 µm, providing intrinsic stability and compactness. By adjusting the central cavity length, stable dual-mode operation is achieved within a single cavity across a broad range of frequency spacings. Devices with different cavity lengths exhibit free spectral ranges from 0.41 nm to 0.65 nm (54-86 GHz), all with side-mode suppression ratios exceeding 30 dB. The device requires only a single metalorganic vapor-phase epitaxy growth and one dry etching step, enabling a compact, thermally stable, and fabrication-tolerant solution. This work establishes a promising dual-wavelength laser platform for microwave photonics and integrated photonic systems.