A. Kaltenbach^a, J. Hofmann^a, D. Seidel^b, K. Lauritsen^b, F. Bugge^a, J. Fricke^a, K. Paschke^a, R. Erdmann^b, and G. Tränkle^a

Published in:

Proc. SPIE 10088, Photonics West, San Francisco, USA, Jan 28 - Feb 02, 1008808 (2017).

Abstract:

A miniaturized picosecond pulsed semiconductor laser source in the spectral range around 560nm is realized by integrating a frequency doubled distributed Bragg reflector ridge waveguide laser (DBR-RWL) into a micro-module. Such compact laser sources are suitable for mobile application, e.g. in microscopes. The picosecond optical pulses are generated by gain-switching which allows for arbitrary pulse repetition frequencies. For frequency conversion a periodically poled magnesium doped lithium niobate ridge waveguide crystal (PPLN) is used to provide high conversion efficiency with single-pass second harmonic generation (SHG). The coupling of the pulsed radiation into the PPLN crystal is realized by a GRIN-lens. Such types of lenses collect the divergent laser radiation and focus it into the crystal waveguide providing high coupling efficiency at a minimum of space compared to the usage of fast axis collimator(FAC)/slow axis collimator (SAC) lens combinations. The frequency doubled output pulses show a pulse width of about 60 ps FWHM and a spectral width around 0.06nm FWHM at a central wavelength of 557nm at 15°C. The pulse peak power could be determined to be more than 300mW at a repetition frequency of 40 MHz.

Keywords:

Distributed Bragg reflector, diode laser, second harmonic generation, yellow-emitting, picosecond pulses, micro-integration.

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