A Low-loss Electro-optic Waveguide Polymer Modulator and its Optimization Design

Abstract

Generally, the core is made up of EO materials in electro-optic waveguide polymer modulators and thus lightwave carrier is modulated in the core. In this case, the loss from chromophores is often large because the most of light power are confined to cores. In order to reduce the optical loss, we presented an approach that the lightwave was modulated only in claddings; that is to say, the EO polymer is only used in claddings and the core material is low-loss passive. Results indicate the propagation loss of this kind of modulator is about 1/3 of the former. Although the modal overlap integral between the microwave and the lightwave weakened under this condition, it could be improved by optimizing the dimension of waveguide. Due to the lower propagation loss, the interaction length of the modulator may be lengthened. Thus, the half-wave voltage can be decreased further. Also, some considerations on optimization design of this modulator are discussed. Especially, the effect of conductor loss and velocity mismatching should be taken into account in order to achieve the theoretical optimal half-wave voltage and the device bandwidth.

A vertical T-electrode modulator with low-loss and high-speed

“…In [8] a capacitatively loaded traveling wave electrode was designed to reduce microwave loss, achieving a low half-wave voltage of 3.4V and a large bandwidth of 67GHz. The work in [9] analyzed in detail the problems to be solved in the design of high-speed traveling wave electrodes, and designed a silicon-based single-channel MZ modulator with a bandwidth of 3dB up to 17GHz. The work in [10] simulated and designed a T-type capacitatively loaded traveling wave electrode based on thin film lithium niobate.…”