Micro-integrated extended cavity diode laser with integrated optical amplifier for precision spectroscopy in space

Summary form only given. GaAs diode laser-based hybrid micro-integration technology meets the demand for precision spectroscopy applications in space for compact, robust, and energy-efficient laser modules. It supports applications at wavelengths ranging from 630 nm to 1200 nm and is already used for quantum optics experiments in space [1].Here, we present a narrow linewidth, high power extended cavity diode laser (ECDL) master oscillator power amplifier (MOPA) laser module (see Fig. 1) for operation as local oscillator of an iodine-based frequency reference on board a sounding rocket. The laser module is based on a versatile technology platform which facilitates integration of any two chips, either active (e.g. laser, amplifier) or passive (e.g. phase modulator) in a single laser module. The module utilizes a micro-optical bench (MioB) consisting of structured aluminium nitride substrates which are encapsulated into a hermetically sealed Kovar housing. The MioB accommodates an ECDL, a tilted ridge-waveguide PA chip, electronics, and fiber coupling assembly to couple light into a single mode, polarization maintaining optical fiber. The footprint of the MioB is 80 x 30 mm2. The cavity of the ECDL is formed by a volume holographic Bragg grating (VHBG) and the front facet of a ridge-waveguide laser chip. The main output of the ECDL is collimated by micro-optical lenses, passed through a micro-optical isolator, and injected into the PA chip by micro-optical lenses. The output of the PA chip is collimated by an aspheric lens, passed through a thin film polarizer and coupled into a single mode, polarization maintaining optical fiber. The laser module features a mass of 750 g, and its form factor corresponds to 125 x 75 x 22.5 mm2.