Mode-Locking Using $\chi ^{(2)}$ Waveguide Arrays

It is demonstrated theoretically that the use of a χ
⁽²⁾
waveguide array in conjunction with a fiber laser cavity is capable of producing self-starting, robust, and stable mode-locking. The χ
⁽²⁾
waveguide array takes advantage of several key effects to enhance the mode-locking stability and effective saturable absorption, including the nonlinear mode-coupling in the waveguide array and the phase-sensitivity of the amplifier. Specifically, the mode-locked pulse phase is locked and stabilized by the pump field upon successive cavity round-trips. The combined advantages of these mode-locking conditions make the χ
⁽²⁾
waveguide-array-based mode-locked laser a technologically attractive photonic device warranting further experimental and theoretical invesgation.