Design of dual mode optical modulators with multi-pass bands

This work demonstrates the design of a novel multiquantum well optical modulator which functions as a reflection and/or transmission modulator at one wavelength whilst allowing three other wavelengths to be transmitted unmodified. The design technique optimizes the Fabry-Perot cavity and the cavity absorption for excellent modulator performance in both reflection and transmission modes. This technique simultaneously optimizes the cavity length for unmodified transmission wavelengths. The simulation shows that this type of modulator can be designed to give a contrast ratio larger than 10 dB for both modes, and exhibits 48% reflectance change and 63% transmittance change at the dual mode operating wavelength for an applied bias of 15 V. The transmittance of the three transmitted wavelengths is close to 100%.