[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - A Multiple-Waveguide Mode-Locked Chip-Laser Architecture

摘要： Frequency combs and analogue to digital sampling are emerging applications that can benefit from advances in elegant, compact, and high performance miniature mode-locked lasers. By virtue of their ‘chip-scale’, and multiplicity of adjacent waveguides, compact cavity planar waveguide devices are suited to efficiently operate in the ~0.5 GHz to 10 GHz pulse regimes. The ultra-fast chip laser platform we have pioneered is based on direct inscription of sub-surface large mode-area waveguides into rare-earth doped fluorozirconate (ZBLAN) glass chips. Multiple waveguides per chip are rapidly written via computer numerically controlled (CNC) ultra-fast laser inscription (ULI); a flexible and advancing waveguide fabrication technique. The guided-wave confinement of these fiber like structures in this bulk gain media ensures efficient pump and cavity mode overlap, robust alignment, and single transverse mode operation. Our initial mode-locking experiments focused on erbium doped ZBLAN chips (sensitized by Yb). These lasers display reasonable cw laser performance, a large single transverse-mode, a wide tunable range covering 1510-1590 nm, and a zero-dispersion wavelength of 1650 nm, thereby reducing the requirement for dispersion compensation. The erbium ytterbium cerium co-doped ZBLAN chips have been demonstrated to produce transform limited mode-locked output near 1.55 μm, with pulse lengths down to 180 fs, and operation up to 3 GHz. In recent work we have also demonstrated cw mode-locking near 1 μm based on Yb doped ZBLAN chip lasers. This talk will provide an overview of chip fabrication, cavity design, mode-locking configuration, and mode-locking results we have achieved. By taking advantage of the multiple waveguide channels, we have demonstrated a cavity that could simultaneously operate adjacent mode-locked erbium lasers using all common cavity components. By slightly modifying one of the cavity lengths, the dual mode-locked laser was shown to operate as an ultra-stable dual frequency comb. This laser possessed the highest mutual coherence reported to date for a passively stabilised dual-comb laser.