Spontaneous Mode Locking and Frequency Comb Generation in a Quantum-dot Laser

A theory is presented for mode-locked quantum-dot lasers used in time- and wavelength-division multiplexing in telecommunications. Multimode semiclassical laser theory is used to treat active-medium nonlinearities resulting in mode competition, gain saturation, carrier-induced refractive index, and combination tones leading to spontaneous mode-locking and frequency-comb creation.