AC/DC field relaxation in multilayer polymer devices: analysis and applications

Electric field distribution and relaxation in a multi-layer polymer system are analyzed based on electromagnetic theory. Analysis showed that the steady state DC electric fields across polymer layers depend on the conductivity of each layer. When a step DC voltage is applied to the electrodes, the field across the waveguide layer will relax exponentially from an initial state to a steady state depending on the dielectric constants and conductivities of polymers. The AC field distribution generally depends on the dielectric constants of the polymer layers at high frequency. At low frequency, the AC field distribution is frequency dependent, and a phase delay occurs. To eliminate the AC/DC field relaxation, the materials used must have matching dielectric properties. The relaxation time (tau) of each polymer layer must be equal at the operating conditions. The analysis of the field relaxation can be applied to the design, fabrication, and test of electro-optic polymer devices. The field relaxation in multi-layer polymers can affect the device bias and operation stability in practical applications. Experimental results showed that stable DC bias can be achieved by optimizing or matching relaxation properties of polymers. Other applications of the field relaxation analysis include polymer poling, device characterization, and new device designs.