We present the status of our efforts to develop very compact and robust diode laser modules specifically suited for quantum optics experiments in the field and in space. The paper describes why hybrid micro-integration and GaAs-diode laser technology is best suited to meet the needs of such applications. The electro-optical performance achieved with hybrid micro-integrated, medium linewidth, high power distributed-feedback master-oscillator-power-amplifier modules and with medium power, narrow linewidth extended cavity diode lasers emitting at 767 nm and 780 nm are briefly described and the status of space relevant stress tests and space heritage is summarized. We also describe the performance of an ECDL operating at 1070 nm. Further, a novel and versatile technology platform is introduced that allows for integration of any type of laser system or electro-optical module that can be constructed from two GaAs chips. This facilitates, for the first time, hybrid micro-integration, e.g. of extended cavity diode laser master-oscillator-poweramplifier modules, of dual-stage optical amplifiers, or of lasers with integrated, chip-based phase modulator. As an example we describe the implementation of an ECDL-MOPA designed for experiments on ultra-cold rubidium and potassium atoms on board a sounding rocket and give basic performance parameters.
Red emitting diode lasers with a narrow spectral line-width and continuous tuning are requested as light sources for
interferometric measurements with nm-accuracy. Tuning ranges of about 25 GHz together with a spectral line-width
smaller than 10 MHz are necessary.
A current-tunable miniaturized 633 nm external cavity diode laser (ECDL) will be presented. The resonator is
formed without moving parts between the front facet of a semiconductor gain medium and a reflection Bragg grating
(RBG). The RBG has a high reflectivity larger than 95% in a small spectral bandwidth, which is approximately
equal to the targeted tuning range. Within this bandwidth, the ECDL is tunable by changing the injection current of
the gain medium. The length of the resonator is selected so short, that the distance between the laser modes is larger
than the tuning range. Herewith, single mode operation should be guaranteed. The device is mounted on an aluminum
nitride bench with a footprint of 5 mm x 10 mm. ECDLs using gain media with different front facet
reflectivities of 30% and 70% will be compared. Moreover, results for a device encapsulated in a silicon based gel
will be presented.
For a device with 30% front facet reflectivity in air, a maximal output power of 10 mW was achieved. The tuning
range without any mode-hops was 34 pm, i.e. 25 GHz. The line-width was smaller than 10 MHz. The emitted beam
was approximately diffraction limited with a M<sup>2</sup> ≈ 1.1 in both directions.