All-active InGaAsP/InP ring cavities for widespread functionalities in the wavelength domain

All-active ring resonator structures allow filter operation as well as laser mode operation, only depending on the driving conditions. Add/drop filter devices based on active InGaAsP/InP have been realized for the 100 and 50 GHz free spectral range. The properties of all pass-filter elements built of active single ring resonators are investigated. A delay time up to 80 ps has been measured for a bending radius R of 250 μm and a coupling ratio of 0.6 to the bus-waveguide. The respective dispersion of ±280 ps/nm is attained within a pass band of 5 GHz. Operating in the laser mode, microring resonator structures with R = 50 μm show a single mode emission spectrum with an optical power output as high as of 6.5 mW per facet.