以同步二次素数码(SQPC)作为时间扩频序列,单重合序列(OCS)作为波长跳频序列,构造了一种 新的二维光正交码SQPC/OCS,并对其误码性能及码字容量进行了理论分析和仿真比较。理论分析 表明:在同码长、同波长数条件下, SQPC/OCS与 2D-QPC误码率相等,但SQPC/OCS波长数可以是任何数,不局限于素数,从而增加波长码片可以降 低误码率;与扩展素数码 (EPC) EPC/OCS相比,SQPC/OCS误码率更低。SQPC/OCS码字容量远远高于2D-QPC和EPC/OCS码 字容量。仿真结果表明:当p=7、q=13时,SQPC/OCS误码率比2D-QPC降低接近2个数量级;当p=11、 q=15时,SQPC/OCS与EPC/OCS相比,当用户数为20时,误码率相差达4个数量级。

A new two-dimensional optical orthogonal code named SQPC/OCS was constructed with synchronous quadratic prime code (SQPC) as time spreading sequence and one-coincidence sequence (OCS) as wavelength hopping sequence. The performances of bit error ratio (BER) and word capacity were compared by analysis and simulation. Theoretical analysis show that SQPC/OCS has the same BER as 2D-QPC (Quadratic prime code) when given the same code length and same number of wavelength, but SQPC/OCS can reduce its BER by increasing the number of wavelength which is not limited to a prime number. Compared with extend prime code (EPC) EPC/OCS, SQPC/OCS gets lower BER. Moreover, the code capacity of SQPC/OCS was much more than that of 2D-QPC and EPC/OCS. The simulation shows that the bit error rate (BER) of SQPC/OCS is nearly two orders of magnitude lower and four orders of magnitude lower than that of 2D-QPC (p=7 and q=13) and EPC/OCS (p=11 and q=15) while the number of synchronous users equals 20, respectively.