Compact, Watt-class 785 nm dual-wavelength master oscillator power amplifiers. (1st December 2022)

• Record Type: Journal Article
• Authors: Müller, André; Maiwald, Martin; Sumpf, Bernd
• Is Part Of: Journal of physics communications. Volume 6:Number 12(2022)
• Publication Date: 2022-12-01
• Subjects: master oscillator power amplifier -- diode laser -- distributed Bragg reflector -- tapered amplifier -- dual-wavelength -- Raman spectroscopy; Physics -- Periodicals; 530.05
• DOI: 10.1088/2399-6528/acac6e
• Languages: English
• ISSNs: 2399-6528

Abstract

Abstract: 785 nm micro-integrated, dual-wavelength master oscillator power amplifiers with a footprint of 5 mm × 25 mm are presented. They are based on Y-branch distributed Bragg reflector ridge waveguide diode lasers and anti-reflection coated tapered amplifiers. In order to reduce the impact of potential optical feedback, devices with master oscillator front facet reflectivities of 5% and 30% as well as with an integrated miniaturized optical isolator have been realized. A comparison up to 1 W shows narrowband dual wavelength laser emission with a spectral distance of 0.6 nm (10 cm −1 ) and individual spectral widths <20 pm. As expected, a higher front facet reflectivity leads to a significant reduction of feedback related mode hops. Longitudinal modes corresponding to the master oscillator resonator length remain within spectral windows <0.15 nm (3 cm −1 ), suitable for applications such as Raman spectroscopy and especially shifted excitation Raman difference spectroscopy. Integrating a compact 30 dB optical isolator completely eliminates the observed optical feedback effects. Lateral beam propagation ratios of 1.2 (1/e 2 ) enable easy beam shaping and fiber coupling. Outside of the experimental comparison, the developed MOPAs provide up to 2.7 W of optical output power available for applications.