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 micromodule. 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‰. The pulse peak power could be determined to be more than 300mW at a repetition frequency of 40 MHz.

Date Published: 20 February 2017
PDF: 7 pages
Proc. SPIE 10088, Nonlinear Frequency Generation and Conversion: Materials and Devices XVI, 1008808 (20 February 2017); doi: 10.1117/12.2250145

Published in SPIE Proceedings Vol. 10088:
Nonlinear Frequency Generation and Conversion: Materials and Devices XVI
Konstantin L. Vodopyanov; Kenneth L. Schepler, Editor(s)