Monolithic optical frequency comb based on quantum dashed mode locked lasers for Tb/s data transmission

Optical frequency combs have great potential for ultra-high bit rate telecommunications e. g. optical orthogonal frequency-division multiplexing superchannels. For frequency comb generation, monolithic Quantum Dash semiconductor mode-locked lasers are very attractive candidates owing to their broadband optical spectrum, inherent intrinsic low noise and compactness. The active region is based on InAs nanostructures grown on InP for operation in the 1.55 mu m window. Owing to enhanced nonlinear effects, a single gain section generates short pulses in the modelocking regime without resorting to an absorber section. An optical bandwidth over 1.3 THz yielding over 100 channels, 10 GHz spaced, is reported. Mode-locking properties are analyzed in the frequency domain using the concept of supermodes. An Allan deviation down to similar to 10(-9) is reported for these passively mode-locked lasers. The low timing jitter, longterm stability and high channel count of these QD based combs are of great potential for Tb/ s data transmission with only one single FP type laser source.