High Speed Polymer Electro-optic Modulators

Organic nonlinear optical (NLO) materials offer potential advantages for applications in photonic devices such as modulators and resonators.  Second-order NLO polymers have been widely studied because they can provide higher optical nonlinearity than  inorganic nonlinear crystals in high speed optical communication and signal processing devices.  Recent progress in design and synthesis of nonlinear EO polymers opens possibilities for low power consumption and broadband operation of photonic devices. For high speed optical modulation, the electrodes must be carefully designed in order to minimize RF loss and to phase matched electrical and optical propagating waves. We are developing high speed optical phase modulators based on an electro-optic polymer from the University of Washington using an in-plane slotline RF electrode structure as shown below.  We’ve achieved an RF transimission loss of 0.3 dB/cmÖHz for an in-plane slotline electrode structure on fused silica.  Using EO polymers with high nonlinear optical coefficients, we expect to be able to reduce the drive voltage to under 1 volt.

Cross section of slotline EO modulator (NLOP=nonlinear optical polymer).

Measured RF transmission S21 as a function of frequency up to 40 GHz for the slotline structure on different substrates.

“High speed electro-optic polymer phase modulator using an in-plane slotline RF waveguide,” D. Park, Y. Leng, J. Luo, A. K.-Y. Jen, W. N. Herman,  Proc. SPIE 7936-7, (2011).