Generation of 425-nm light by waveguide frequency doubling of a GaAlAs laser diode in an extended-cavity configuration

A blue output power of 1.2 mW at 425 nm was generated using a periodically poled KTP waveguide for frequency doubling of a grating tuned, extended-cavity laser containing an antireflection-coated GaAlAs SQW-GRINSCH laser diode as the gain element. A normalized conversion efficiency of 127%/W cm2 was achieved in the extended-cavity configuration.