Wavelength tunable laser using an interleaved rear reflector

A novel integrated reflector concept for use in widely tunable semiconductor lasers is introduced. Two concatenated Fabry-Pérot cavities with low partial reflections and different cavity lengths are interleaved to realize a wavelength-selective reflective element. Differential current injection in the interleaved cavities is used to tune the reflection peak. The reflector is integrated in an all-active multisection device. The laser tunes across 37 wavelength channels on a 100-GHz grid over a wavelength span of 30 nm. The linewidth of each mode is <7 MHz while the power deviation is <6 dB.