线性组合码(LCC)具有码族容量大、误码率(BER)低等优点,是实现光码分多址(OCDMA)的一种有效手段。通过改变组成线性组合码的子码字数可以实现多速率传输。利用基于线性组合码的二维时域/频域光纤光栅编/解码器,建立了多速率随机接入实验平台,成功实现了双用户发送和双用户接收的双速率光码分多址数据通信。线性组合码选用素数跳频码(PC)为子码族,实验中取素数为3的素数码控制时间扩频和波长跳频。实验验证了线性组合码多速率光码分多址接入系统方案的可行性。

Linearly combinated code (LCC) possesses the feature of large capacity, low bit error rate (BER). It is an effective way to realize the optical code division multiple access (OCDMA). Multi-bit rate transmission can be carried out by changing the number of sub-codewords in a LCC. Multi-bite rate random access experiment is set up by employing two-dimension time/wavelength domain fiber grating encoder and decoder based on the linearly combinated code. The sub-codewords of linearly combinated code come from prime code (PC)/PC set. In the experiment, spreading frequence of time domain and wavelength hopping are controlled by prime code with prime 3. The transmitting and receiving experiments for two users in every end are successfully executed. The feasibility of multi-bit rate optical code division multiple access system is experimentally demonstrated.