High Power Narrow Spectrum Second-Order DBR Laser Diode Operating Over a Wide Temperature Range

Distributed Bragg Reflector laser diode (DBR-LD) plays a crucial role as pump sources due to its wavelength stability. This work firstly presents a $100~\mu $ m wide $2^{\mathrm {nd}}$ -order DBR-LD with surface etched grating. Based on scattering matrix method (SMM) and eigenmode expansion (EME) method, the $2^{\mathrm {nd}}$ -order grating was designed as a period of 288.1 nm and a duty of cycle of 25%. Using ultra violet nanoimprint lithography (UV-NIL) and Inductively Coupled Plasma (ICP) dry etching technique, the grating was firstly fabricated with a depth of $1~\mu $ m from surface. The laser diode achieved a maximum output power of 9.52 W with a full width at half-maximum (FWHM) spectral width of 0.4 nm in CW mode and an average wavelength drift coefficient of 0.0645 nm/°C over a wide temperature range from $- 10~^{\circ }$ C to $100~^{\circ }$ C in pulsed mode, expanded the operating temperature.