title: Locking and wavelength selection of an ultra-collimated single-mode diode laser bar by a volume holographic grating.
abstract: Wavelength-locking by a volume holographic grating (VHG) is reported for a diode laser bar with 49 single mode emitters, fitted with a dual-axis collimation phase-plate for smile elimination and excellent beam pointing correction. The much-improved VHG feedback with the ultra-collimated array beam gives 100% wavelength locking at 975 nm over a 17°C temperature range and external cavity lengths up to 110 mm. This enables a folded cavity configuration to provide a fully-locked array with wavelength selection into 200 pm channels over an 8 nm band, suitable for multi-bar dense wavelength-combining.
authors.affiliation: School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh, EH14 4AS, UK.
authors.forename: Natalia
authors.initials: N
authors.lastname: Trela
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Baker
authors.forename: Denis R
authors.initials: DR
authors.lastname: Hall
mesh_terms: D004867:Equipment Design; D019544:Equipment Failure Analysis; D006696:Holography / Q000295:instrumentation*; D007089:Image Enhancement / Q000295:instrumentation*; D054023:Lasers, Semiconductor; D007909:Lenses; D012031:Refractometry / Q000295:instrumentation*