A New Family of Optical Code Sequences for Spectral-Amplitude-Coding Optical CDMA Systems

Abstract

A new code structure for spectral-amplitude-coding optical code-division multiple-access system based on double-weight (DW) code families is proposed. The DW code has a fixed weight of two. By using a mapping technique, codes that have a larger number of weights can be developed. Modified double-weight (MDW) code is a DW code family variation that has variable weights of greater than two. The newly proposed code possesses ideal crosscorrelation properties and exists for every natural number n. Based on theoretical analysis and simulation, MDW code is shown here to provide a much better performance compared to Hadamard and modified frequency-hopping codes.

Complementary Detection Technique to Performance Analysis of RZandNRZ on MDW Code in FTTH Network

“…The two diagrams are used for simulation set up. These two data formats have found widespread use although the RZ data format requires twice the NRZ transmission bandwidth, it is quiet useful in application [1]. …”

“…Although return-to-zero (RZ) hold a provision for synchronization, it motionless has a DC component resulting in "baseline wander" during long strings of (o) or (1) bits, just like the line code nonreturn-to-zero. The RZ and NRZ data signals formats are showing in figure 1.a&b respectively [1].…”

Multiple access interference elimination with enhanced chromatic dispersion tolerance in SAC OCDMA

“…This differs from CS where all chips are detected including the overlapping chip(s) for further cancellation. This technique is different from the direct detection technique used in wave-length division multiplexing (WDM) whereby the number of chips detected in DD depends on the number of the non-overlapped weights where it is always code weight divided by two (W/2) for the case of our code [5,6,7]. On the other hand, WDM only detects one wavelength.…”

“…Our scheme also reduces the number of filters and photodetectors at the receiver [5,7]. In addition to the detrimental effects of MAI, dispersion is another major contributing factor to performance degradation of OCDMA system.…”

New code structure for spectral amplitude coding in OCDMA system

“…OCDMA system have been investigated for about two decades and received a lot of attention [1,2,3,4]. This is due to its excellent performance, such as asynchronous access to the netowork [5], high security operation [6], and high capacity in burst networks [7].…”