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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100~\mu $ </tex-math></inline-formula> m wide <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2^{\mathrm {nd}}$ </tex-math></inline-formula>-order DBR-LD with surface etched grating. Based on scattering matrix method (SMM) and eigenmode expansion (EME) method, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2^{\mathrm {nd}}$ </tex-math></inline-formula>-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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1~\mu $ </tex-math></inline-formula> 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- 10~^{\circ }$ </tex-math></inline-formula> C to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100~^{\circ }$ </tex-math></inline-formula> C in pulsed mode, expanded the operating temperature.