Performance enhancement of the 2-D wavelength-hopping/time-spreading synchronous OCDM system using a heterodyne detection receiver and PPM signaling

Abstract

Two-dimensional wavelength-hopping/time-spreading synchronous optical code-division multiplexing systems using a heterodyne detection receiver and pulse-position modulation (PPM) signaling are investigated. Prime sequences are used as signature code for both wavelength hopping and time spreading. Performance of the proposed systems is theoretically analyzed taking into account various kinds of noise and interference, including multiple access interference, optical beating interference, crosstalk, and receiver noise. We also compare the performance of the proposed systems with the conventional ones using ON-OFF keying signaling. Numerical results show the improvement in both number of users and optical power gain with a proper selection of PPM word length M.

Optical power budget enhancement in next-generation DDO-OFDM-based optical access networks using square root module

“…OBI is not present in the downstream direction because data of all ONUs are combined at the electrical stage at OLT and then modulated by a single optical wavelength. The mean square value of OBI noise in the upstream direction can be defined as [22] …”

FWM impairment in multi-wavelength optical code-division multiplexing systems

“…And as we adopt the theoretical analysis from [6]- [11], only analysis related to the impact of FWM will be presented. Furthermore, in order to focus on the impact of FWM, the group velocity dispersion (GVD) on the system performance is neglected.…”

Beat noise cancellation in 2-D OCDMA systems using Optical Hard-limiter Array

“…There have been several approaches proposed to improve the performance of OCDMA systems in the presence of beat noise [5]- [7]. In the first approach, forward error coding is used to improve the ability of detecting and correcting errors [5].…”

“…Moreover, redundant information needs to be added, which increases the system bandwidth. The other approach, which can reduce multiple access interference (MAI) and beat noise, is the usage of M -array pulse position modulation (PPM) [6], [7]. However, the systems using PPM is more affected by dispersion due to the reduction of pulse width, especially when M is large.…”

“…However, the systems using PPM is more affected by dispersion due to the reduction of pulse width, especially when M is large. The last approach, which can mitigate beat noise and effectively improve the system performance, is to use heterodyne detection receiver [7]. Nevertheless, the deployment of this method is still limited due to the complex of the systems.…”