Electroabsorption modulator performance predicted from band-edge absorption spectra of bulk, quantum-well, and quantum-well-intermixed InGaAsP structures

Band-edge absorption spectra from bulk, quantum-well, and quantum-well-intermixed InGaAsP material are collected and compared using photocurrent spectroscopy. The expected performances of ideal electroabsorption modulators fabricated from these materials are predicted and compared using the band-edge absorption data. A graphical method for simultaneously considering chirp, insertion-loss, extinction-ratio, and tuning range is presented, and is used to compare the suitability of the various materials for electroabsorption modulator applications. The quantum-well material is shown to be superior to bulk material for most EAM applications. Quantum wells with 85 meV conduction band depth and 80 Å width are shown to be superior to quantum wells with 120 meV conduction band depth and 65 Å width. Both well designs exhibit strong excitons. Finally, the effect of quantum-well intermixing is considered, and the expected performances of quantum-well-intermixed electroabsorption modulators are presented.