SOA-Integrated Widely Tunable Laser Array for All-Solid Lidar Application

A SOA-integrated widely tunable laser array is proposed and demonstrated in this letter. The semiconductor optical amplifier (SOA) is coupled to the tunable V-cavity laser through a deeply etched trench. An angled etched facet is used at the output of the SOA, in lieu of an anti-reflection (AR) coating, to effectively attenuate output facet reflection, while keeping the output beam perpendicular to the cleaved chip edge to facilitate external coupling. No complex grating or multiple epitaxial growth is needed. For the individual device, a tuning range of 36.3 nm is achieved by adjusting single electrode current with a side-mode suppression ratio of over 38 dB. A maximum output power of 32 mW at 5 °C is obtained. An array consisting of four SOA-integrated tunable lasers with different bandgaps are realized through three-step quantum well intermixing (QWI), thereby enabling a total tuning range of 103 nm.