Megahertz linewidth from a 1.5 μm semiconductor laser with HeNe laser injection

Abstract

The linewidth of a 1.5 μm semiconductor laser has been reduced from > 1 GHz to < 1.5 MHz by injection locking the laser to the low-power narrow-linewidth output from an HeNe laser operating at 1.523 μm. A collimated-beam power of 750 μW was obtained in the injection-locked semiconductor laser mode.