Capacity enrichment OCDMA based on algorithm of novel flexible cross correlation (FCC) address code

The flexible cross-correlation (FCC) address code for Spectral-Amplitude Coding Optical Code-Division Multiple-Access (SACOCDMA) systems has been developed.The FCC code has advantages, such as flexible cross-correlation property at any given number of users and weights, as well as effectively suppressed the impact of phase-induced intensity noise (PIIN) and multiple-access interference (MAI) cancellation property.The results revealed that the FCC code can accommodate 150 users, where FCC code offers 66 %, 172 %, 650 % and 900 % improvement as a contrast to 90, 55, 20 and 15 number of users for dynamic cyclic shift (DCS), modified double weight (MDW), modified frequency hopping (MFH) and Hadamard codes, respectively, for a permissible bit error rate (BER) of 10−9

Dynamic evolving neural fuzzy inference system equalization scheme in mode division multiplexer for optical fiber transmission

The performance of optical mode division multiplexer (MDM) is affected by inter-symbol interference (ISI), which arises from higher-order mode coupling and modal dispersion in multimode fiber (MMF). Existing equalization algorithms in MDM can mitigate linear channel impairments, but cannot tackle nonlinear channel impairments accurately. Therefore, mitigating the noise in the received signal of MDM in the presence of ISI to recover the transmitted signal is important issue. This paper aims at controlling the broadening of the signal from MDM and minimizing the undesirable noise among channels. A dynamic evolving neural fuzzy inference system (DENFIS) equalization scheme has been used to achieve this objective. Results illustrate that nonlinear DENFIS equalization scheme can improve the received distorted signal from an MDM with better accuracy than previous linear equalization schemes such as recursive‐least‐square (RLS) algorithm. Desirably, this effect allows faster data transmission rate in MDM. Additionally, the successful offline implementation of DENFIS equalization in MDM encourages future online implementation of DENFIS equalization in embedded optical systems

Comparison of Different Wavelength Propagations over Few-Mode Fiber based on Space Division Multiplexing in Conjunction with Electrical Equalization

Abstract—Nonlinearities in optical fibers deteriorate system performances and become a major performance-limiting issue. This article aims to investigate the compensation of nonlinear distortions in optical communication systems based on different wavelength propagations over few-mode fiber (FMF). The study adopted Space Division Multiplexing (SDM) based on decision feedback equalizer (DFE). Various transmission wavelength of the FMF system is applied to mitigate the attenuation effect on the system. In this paper, different wavelengths (780, 850 and 1550 nm) are used in SDM. Extensive simulation is performed to assess the attenuation and Bit Error Rate (BER) in each case. The results show that the wavelength of 1550 nm produces higher power and less attenuation in the transmission. Furthermore, this wavelength produces the best distance with less BER compared to 780 nm and 850 nm wavelengths. Moreover, the validations show improvement in BER and eye diagram

Interaction of a strongly focused light beam with single atoms

Ph.DDOCTOR OF PHILOSOPH

PERFORMANCE ANALYSIS OF OPTICAL CDMA SYSTEM USING VC CODE FAMILY UNDER VARIOUS OPTICAL PARAMETERS

The intent of this paper is to study the performance of spectral-amplitude coding optical code-division multiple-access (OCDMA) systems using Vector Combinatorial (VC) code under various optical parameters. This code can be constructed by an algebraic way based on Euclidian vectors for any positive integer number. One of the important properties of this code is that the maximum cross-correlation is always one which means that multi-user interference (MUI) and phase induced intensity noise are reduced. Transmitter and receiver structures based on unchirped fiber Bragg grating (FBGs) using VC code and taking into account effects of the intensity, shot and thermal noise sources is demonstrated. The impact of the fiber distance effects on bit error rate (BER) is reported using a commercial optical systems simulator, virtual photonic instrument, VPITM. The VC code is compared mathematically with reported codes which use similar techniques. We analyzed and characterized the fiber link, received power, BER and channel spacing. The performance and optimization of VC code in SAC-OCDMA system is reported. By comparing the theoretical and simulation results taken from VPITM, we have demonstrated that, for a high number of users, even if data rate is higher, the effective power source is adequate when the VC is used. Also it is found that as the channel spacing width goes from very narrow to wider, the BER decreases, best performance occurs at a spacing bandwidth between 0.8 and 1 nm. We have shown that the SAC system utilizing VC code significantly improves the performance compared with the reported codes

Analysis of Near-infrared (NIR) spectroscopy for chlorophyll prediction in oil palm leaves

Oil palm nutrient content is investigated with using chlorophyll as a representative factor correlated with NIR spectroscopy spectral absorbance. NIR spectroscopy method of sampling have been tested to overcome time consuming, complex chemical analysis procedure and invasive sampling method in order to identify chlorophyll content in an oil palm tree. Spectral absorbance data from range 900 nm to 1700 nm and chlorophyll data, then tested through five pre-processing methods which is Savitzky-Golay Smoothing (SGS), Multiplicative Scatter Correction (MSC), Single Normal Variation (SNV), First Derivative (1D) and also Second Derivative (2D) using Partial Least Square (PLS) regression prediction model to evaluate the correlation between both data. The overall results show, SGS has the best performance for preprocessing method with the results, the coefficient of determination (R2) values of 0.9998 and root mean square error (RMSE) values of 0.0639. In summary, correlation of NIR spectral absorbance data and chlorophyll can be achieved using a PLS regression model with SGS pre-processing technique. Thus, we can conclude that NIR spectroscopy method can be used to identify chlorophyll content in oil palm with using time saving, simple sampling and non-invasive method

Performance analysis of wavelength multiplexed SAC OCDMA codes in beat noise mitigation in SAC OCDMA systems

In this paper we investigate the use of wavelength multiplexed spectral amplitude coding (WM SAC) codes in beat noise mitigation in coherent source SAC OCDMA systems. A WM SAC code is a low weight SAC code, where the whole code structure is repeated diagonally (once or more) in the wavelength domain to achieve the same cardinality as a higher weight SAC code. Results show that for highly populated networks, the WM SAC codes provide better performance than SAC codes. However, for small number of active users the situation is reversed. Apart from their promising improvement in performance, these codes are more flexible and impose less complexity on the system design than their SAC counterparts

Design & investigation of 10x10 gbit/s MDM over hybrid FSO link under different weather conditions and fiber to the home

In this paper, we design and investigate 10-channels of mode division multiplexer (MDM) over hybrid free-space optics (FSO) link in several weather conditions to achieve the maximum possible medium range and fiber to the home (FTTH) for high bandwidth access networks. System capacity can be effectively increased with the use of MDM over hybrid FSO-FTTH. In this study, a 10-channel MDM over FSO-FTTH system has been analyzed in different weather conditions that operate at 1550 nm wavelength. The simulated system has transmitted 100 Gbit/s up for a distance of 3200 meters FSO in superbly clear weather condition. It also transmitted 100 Gbit/s up for a distance of 650 meters FSO during heavy rain. The validation of this study is measures based on eye diagrams bit-error rates (BER) that have been analyzed

Effective design for optical CDMA based on radio over fiber (RoF) technique

In this paper, the performance of OCDMA coding systems utilizing the radio over fiber (RoF) technique is presented. It has been done by means of conventional OptiSystem simulation tools, where the propagation of radio signals up to 50 km using standard single mode fiber (SMF) was investigated. The analysis was made based on the performance of eye diagram, bit rate, bit error rate and optical received power