中文摘要：

提出了一种基于SiO_2平板波导技术,由两端口的定向耦合器、移相器和光延时线构成的全光离散傅里叶变换器（ODFT）。研究了该器件的原理,设计和优化了一个4×40 Gb/s的全光傅里叶变换芯片,并且给出了器件的设计细节和实现方法。在此基础上又设计了一个4×40 Gb/s的全光正交频分复用（OFDM）系统,消除了系统中的电子瓶颈。用VPItransmissionMaker（VPI）对该系统进行了仿真,并与采用幅度调制和差分相位调制方式的系统进行了对比。结果表明,基于全光傅里叶变换器的全光正交频分复用系统性能优越,经过320 km的传输后,误码率（BER）小于3×10~（-11）。全光正交频分复用是一种有潜力的高速长途传输技术。

英文摘要：

An all-optical discrete Fourier transformer（ODFT） based on SiO_2 plamar lightwave circuit（PLC） technologies and made up of optical directional couplers,phase shifters,and optical delay lines is designed.Whose principle is investigated and an ODFT chip operating at 4×40 Gb/s is designed and optimized.Detailed designation and implementation methods are also given.Based on that,an all-optical orthogonal frequency division multiplexing （OFDM） transmission system is designed,eliminating the processing speed introduced by electronics as in conventional OFDM systems.The VPItransmissionMaker V7.6 is used to evaluate system performances.Simulation results prove the effectiveness of the all-optical OFDM system.The bit error rate（BER） is lower than 3×10~（-11） after transmission through 320 km in the optical fibers.All-optical OFDM has been treated as a good candidate for the long-haul and high-speed transmission technology.