设计了一种高线性度、无偏置聚合物Y型耦合器电光调制器，它由Y型分束器、Y型合束器、两节推挽极化电光耦合波导构成的电光区和一个微带行波电极构成，给出了器件结构并对其参数做了优化。通过对施加的电学调制信号做傅里叶变换并结合器件的传递函数，给出了一种新型数值方法来建模和表征器件的静态和动态特性，推导并得到了器件的状态函数、静态响应、调制响应、三阶内调响应等表达式。计算和分析结果显示，器件的半波电压为2.69 V；3 dB调制带宽约为143 GHz；当调制系数为1%~10%时，基频信号对器件所产生三阶内调噪声的抑制比为60 dB~90 dB。所给出的理论和相关公式也可用于具有Y型耦合器结构的类似电光器件（如电光开关）的设计、建模和分析。

A high-linear bias-free polymer Y-type coupler electro-optic (EO) modulator is proposed, which consists of Y-type splitter, Y-type combiner, two-section EO region consisting of a pair of push-pull poled waveguides, and a microstrip line electrode. Device structure is proposed and its parameters are optimized. Using Fourier transformation on the applied electric modulation signal and combing the transfer function of the device, a novel formulation technique is presented to model and characterize the device′s static and dynamic performances. Formulas and expressions are derived, with respect to state function, static response, modulation response, third-order intermodulation response, etc. Calculation and analysis results indicate that, the half-wave voltage of the modulator is about 2.69 V, and the 3 dB modulation bandwidth is about 143 GHz. As the modulation coefficient is within the range of 1%~10%, the suppression degree of the fundamental signal on the third-order intermodulation distortion signals is as high as 60 dB~90 dB. The proposed theory and related formulations can also be used to the design, modeling and analysis of a similar device based on Y-type coupler structure.