Highly sensitive InP-based phase modulators based on stepped quantum wells

The active layer of our modulators is based on the stepped quantum wells. The absorption spectrum of the quantum wells was modeled using an effective mass approach, and the excitonic effect was modeled with a variational method. Modulator structures are based on GaInAsP quaternary system, and are grown by low-pressure metal organic vapor phase epitaxy (MOVPE) on n-type InP substrates. The thickness of the active layer in all of the designs is kept at -0.4 /spl mu/m by adjusting the number of quantum wells. Composition and thickness of the other layers are nominally the same for all of the structures. The material is processed into planar and index guided waveguides for measurements.