Optical phase characterization of active semiconductor microdisk resonators in transmission

Abstract

The optical phase characteristics of an indium phosphide (InP) vertically coupled microdisk were experimentally demonstrated. Overcoming the material losses by injecting current into the active quantum well microdisk layer has allowed us to observe the phase behavior in all three coupling regimes. The ability to tune the resonant wavelength of this device makes it suitable for use as a phase modulator or tunable optical delay element.

Polymer microring coupled-resonator optical waveguides

“…The spectral measurements were straightforward wherein we detected the transmitted output power as a function of the wavelength scanned by a tunable laser. The group delay measurement was performed using an RF phase-shift technique [17], [18]. Fig.…”

A study of the linearity of optical micro-resonator-based modulators

“…However, the roughness of the inner and outer sidewalls of a micro-ring would contribute to a larger scattering loss than a microdisk with just an outer sidewall. This may reduce the unloaded quality factor of the micro-rings and make them in general harder to overcouple [2].…”

“…Close to the lasing threshold all losses are compensated by the gain and a flat transmission response is expected. The phase of an overcoupled microdisk then goes through 2p across the resonance, and wavelength tuning of the phase response is possible [2]. Hence, a microdisk that is coupled to one arm of a MZ interferometer can work as an intensity modulator.…”

“…We can introduce a gain medium (such as a few quantum wells inside the microdisk) to overcome microdisk internal losses [2] and make them overcoupled. Close to the lasing threshold all losses are compensated by the gain and a flat transmission response is expected.…”

“…This structure, due to relative ease of integration, has become increasingly important as a building block for photonic integrated circuits (PIC's). Both passive and active devices have been demonstrated, including channel dropping filters, tunable resonant filters and switches, laser sources, WDM demultiplexers, and phase and intensity modulators for both digital and analogue applications in optical communications [1,2].…”