title: 40 GHz mode-beating with 8 Hz linewidth and 64 fs timing jitter from a synchronized mode-locked quantum-dash laser diode.
abstract: Linewidth narrowing of the radio frequency beat-tones and the optical-modes is experimentally investigated in a ∼40 GHz quantum-dash mode-locked laser diode subject to optical injection of 10 GHz pulses. In comparison to the 75 kHz linewidth exhibited by the beat-tones in passive mode-locking conditions, a remarkable reduction to less than 8 Hz is achieved when the laser is under optical injection. From this beat-tone signal, an integrated root-mean-square timing jitter of 64 fs is calculated. In addition, a quadratic profile of the optical linewidth with the wavelength is observed in active locking, reaching a minimum of 1.7 MHz for the longitudinal modes around 1530 nm and progressively increasing to 37.4 MHz for modes at 1525 nm.
authors.affiliation: The RINCE Institute, School of Electronic Engineering, Dublin City University, Glasnevin, Dublin 9, Ireland.
authors.forename: Ramón
authors.initials: R
authors.lastname: Maldonado-Basilio
authors.forename: Sylwester
authors.initials: S
authors.lastname: Latkowski
authors.forename: Severine
authors.initials: S
authors.lastname: Philippe
authors.forename: Pascal
authors.initials: P
authors.lastname: Landais