High-frequency, low-crosstalk modulator arrays based on FTC polymer systems

A novel electro-optic polymer, Furan TetraCyano Indane (FTC) has been utili sed in the fabrication of low V-pi, high-speed, travelling-wave Mach-Zehnde r modulator arrays. The modulators were realised with microstrip transmissi on lines that were optimised resulting in a line loss of 3.64dB/cm at 40GHz . Mach-Zehnder modulators based on this design with 1.62cm interaction leng th resulted in devices with V-pi < 5V and a reasonably fiat frequency respo nse up to 40GHz. Electrical crosstalk measurements were also conducted on a djacent modulators separated by 400 mu m in a modulator array. Without the implementation of any crosstalk reduction techniques, the measurement resul ts indicated a crosstalk level of < -40dB in the frequency band between 0 a nd 40GHz. These impressive results were a consequence of the low dielectric constant of the polymer material at microwave frequencies and of the small lateral dimensions of the microstrip lines.