Grating-based external cavity QC lasers offer broad wavelength tuning [1,2]. On a fine scale, λ modulation and locking require accurate intra-cavity phase control of at least 2 π. However, some realistic aspects of QC lasers make this fine control challenging. These include short-pulse operation, which makes phase tuning with injection current ineffective, long wavelength, which makes piezoelectric cavity length tuning inconvenient with high voltage, and most significantly, degraded facet AR-coating of the Fabry-Perot (FP) gain chip that results in FP mode hopping.
© 2003 Optical Society of AmericaPDF Article