Fully Integrated CMOS-compatible mode-locked lasers

Abstract

The field of integrated photonics has already revolutionized optical communications and is making rapid advances in signal processing, light detection and ranging, optical sensing, bio-medical diagnostics and imaging, and military-related applications. Large and complex radio-frequency and optical systems could be potentially replaced with compact, power-ecient, alignment-free, cost-effectively mass-produced integrated photonics components. An on-chip high repetition-rate mode-locked laser is a key enabler of many integrated photonics applications, such as all-optical sampling, on-chip frequency combs, low phase noise microwave oscillators, photonic ADCs and others. First-ever fully-integrated on-chip mode-locked lasers are demonstrated in this work, fabricated using a CMOS-compatible process. The lasers have no o-chip elements other than the pump laser, which could be easily co-packaged. 1900nm and 1550nm lasers are designed, fabricated and characterized. For 1900nm central wavelength lasers, several dierent laser configuration are demonstrated, with repetition rates of 690MHz and 1.2GHz. Q-switched, Q-switch-mode-locked, and CW mode-locked laser operation was demonstrated, with the shortest pulse durations of 250fs. The smallest foot-print of one laser is 23.6mm x0.78mmx0.6mm. In addition, first-ever fully-on-chip CMOS-compatible mode-locking element based on Kerr nonlinearity is demonstrated for 1550nm and 1900nm laser wavelengths. Demonstrated modulation depths for 1900nm and 1550nm mode-locking devices are 9% and 2.5% respectively. The work in this thesis presents the first-ever demonstration of fully-onchip CMOS compatible mode-locking device, as well as first-ever CMOS-compatible mode-locked lasers with no o-chip components.