Abstract

It is possible to obtain efficient second -harmonic generation (SHG) in quasi-phasematching (QPM) waveguides^1.2 with-low power lasers, and a stable laser diode-based unit emitting blue light has been foreseen for some time, the bandwidth for SHG to blue light is narrow ( typically 0.06 nm/cm) for QPM waveguides. This requires a strict control of the laser spectrum to avoid frequency drift or mode hops away from phasematching, and thereby fluctuations in the SHG signal. High-power laser diodes normally have low reflecting coatings on the output face that make them sensitive to feedback, and frequency stabilization will hence be necessary if they should be used as pump sources in waveguide SHG.

© 1993 Optical Society of America