Monolithic 2.5 GHz Quantum Well InGaAsP Extended Cavity Modelocked Ring Laser with an Integrated Phase Modulator

A passively mode locked extended cavity quantum well ring laser at 1.58 μm with repetition rate of 2.5 GHz in the form of a photonic integrated circuit is presented. The device is realized using InP based active-passive integration technology. The 33mm long cavity contains gain, saturable absorption and passive waveguide sections as well as a phase shifter sections to enable fine tuning of the spectral position of the lasing modes. Passive mode-locked operation and with wavelength tuning of the laser modes are experimentally demonstrated. This laser is the lowest reported repetition rate for a monolithically integrated ring laser.