Monolithically integrated InP-based modelocked ring laser systems

In this paper we report on the progress in the development of modelocked ring lasers that are integrated on a single chip in the InP/InGaAsP material system. With the current optical integration technology it is possible to integrate quantum well optical amplifiers, phase modulators and passive optical components such as waveguides, splitters and spectral filters as standardized building blocks on a single chip. Using such standardized components a number of passively modelocked ring laser devices have been realized in a standardized fabrication process. Results from a few of these devices are presented here. We have observed a record width of the frequency comb from a modelocked quantum well ring laser operating at a 20 GHz repetition rate. The optical coherent comb is centered around 1542 nm and has a 3 dB bandwidth of 11.5 nm. A minimum pulse width of 900 fs was observed. A second device that is highlighted is a modelocked ring laser with a 2.5 GHz repetition rate. Its 33 mm long cavity is fitted onto a chip of 2.2x1.9 mm(2). One of the goals of this work is to make such designs available in device libraries for use in more complex integrated optical systems using standardized technology platforms.