Dispersion-Free Traveling Wave Plasmon/Polymer Waveguide Modulator

Physical Optics Corporation (POC) proposes a traveling wave plasmon/polymer waveguide modulator. Conventional EO modulators suffer from small modulation bandwidths (usually much less than 100 GHz) due to the large walk-off between the propagation of the microwaves and optical waves. Additionally, the small index modulation associated with linear electrooptic coefficients requires a long electrode length (mm to cm). The proposed plasmon waveguide modulator, in conjunction with an EO polymer, provides a modulation scheme that has a small interaction length (about 100 um). No dispersion between the optical waves and the microwaves is expected. Employment of a collinear microstrip line generates a much better overlap integral between the optical and microwave signals, and power consumption is reduced in comparison with conventional coplanar electrode structures used for LiNbO3 and GaAs EO modulators. The optical bandwidth is greatly enhanced by adjusting the input coupling angle and the bouncing angle of the substrate-guided wave, which has a continuous guiding spectrum as long as the total internal reflection (TIR) criterion is satisfied. A plasmon waveguide modulator will be demonstrated in Phase I. The microstrip line suitable for transmitting a 100 GHz signal will also be tested.