Search

Spectral Amplitude Coding-Optical Codes Division Multiple Access (SAC-OCDMA) is a future multiplexing technique that witnessed a dramatic attraction for eliminating the problems of the internet in optical network field such as multiple-user access and speed's growth of the files or data traffic. In this research article, the performance of SAC-OCDMA system based on two encoding–decoding multidiagonal (MD) and Walsh Hadamard (WH) codes is enhanced utilizing three different schemes of dispersion compensating fiber (DCF): pre-, post- and symmetrical compensation. The system is simulated using Optisystem version 7.0 and Optigrating version 4.2. The performance of the proposed system is specified in terms of bit error rate (BER), Q-factor and eye diagram. It has been observed that the compensated system based on MD code is performs much better compared to the system based on WH code. On the other hand, the compensated SAC-OCDMA system with symmetrical DCF has the lowest values of BER and largest values of Q-factor, so it is considered the best simulated scheme contrasted with pre- and post-DCF. [ABSTRACT FROM AUTHOR]

This report presents a comprehensive approach to dispersion management, including various techniques, mathematical analysis, and their advantages and disadvantages in different scenarios. A deep mathematical analysis of chirped fiber Bragg grating (CFBG) is conducted for various chirping techniques and apodization profiles, highlighting the importance of this aspect in dispersion management. Additionally, a detailed study of the implementation of CFBG and dispersion compensating fiber (DCF) is performed to determine which technique is suitable for long-haul links and which is best for WDM networks, both for low and high capacity. The report also sheds light on how dispersion compensation techniques can be useful in mm wave propagation. The paper provides new insights into the field of dispersion management and the results of the study make it an interesting and valuable addition to the literature. [ABSTRACT FROM AUTHOR]

In this paper, we design an ultra-dense wavelength division multiplexing (UD-WDM) system with 400 channels based on the differential phase-shift keying (DPSK) modulation technique and compared the performance of the proposed system with the one not having the DPSK modulation technique. The performance is investigated in terms of quality factor (Q-Factor) and bit error rate (BER) with varying transmission distance from 30 to 250 km and the number of channels from 50 to 400 for bit rates of 10 and 40 Gb/s per channel. The findings showed that the system with the DPSK modulation technique outperformed the system without the DPSK modulation technique for both 10 and 40 Gb/s bit rate per channel. The reported values of BER and Q-factor with transmission distance for DPSK modulated system for 10 Gb/s bit rate are around 10–9 and 14 dB respectively and for 40 Gb/s bit rate, the values are around 10–6 and 13.2 dB respectively, which are better than the values in the system without DPSK modulation technique which reported BER of around 10–3 and Q-factor of 4.2 dB for 10 Gb/s bit rate and BER of around 10–2 and Q-factor of 4.1 dB for 40 Gb/s bit rate. When the number of channels is taken into consideration instead of distance, the values of BER and the quality factor for DPSK modulated system is reported around 10–8 and 13.2 dB for 10 Gb/s bit rate and 10–6 and 9.2 dB for 40 Gb/s bit rate respectively which are better than the values in the system without DPSK modulation which reported BER of around 10–4 and Q-factor of 4.1 dB for 10 Gb/s bit rate and BER of around 10–1 and Q-factor of 4 dB for 40Gb/s bit rate. In the end, the eye diagrams for both the systems are compared and found better eye-opening in DPSK modulated system than the system without the DPSK modulation technique. [ABSTRACT FROM AUTHOR]

The transmission of the high data rate and information over the optical fiber is restricted by various dispersion phenomenon which further results into intersymbol interference (ISI). This article proposes two different methodologies for optical fiber deformation aiding vibration monitoring one using the pin diode as a photo-detector device and another manifesting the avalanche photo-detector. The novelty of this article lies in optical signal conversion using photo-detector processing followed by low pass Gaussian filter in order to reduce the extra contortion. This work is approaching electronic dispersion compensation technique (EDC) for compensation of chromatic dispersion at two distinct bit rates of 25 and 30 Gbps over 120 km of single mode fiber. Both the diodes have tested for theory performance using factors like Q-factor, bit error rate and eye height. It is found that pin diode is exhibiting a quality factor of 67.150 and 40.5944 at 25 and 30 Gbps, respectively. When avalanche pin diode is used at the same data rates, quality factor of 73.0240 and 43.3523 are obtained, respectively. Hence, use of avalanche photodiode at high bit rates is utilized and the simulations showed the optimum photo-diode for efficacious dispersion compensation at such a long transmission distance. [ABSTRACT FROM AUTHOR]

Spectral amplitude coding optical code division multiple access (SAC-OCDMA) is a promising innovation for burst and asynchronous environment. This paper endeavors to analyze the efficacy of the proposed optimum SAC-OCDMA system by utilizing enhanced double-weight (EDW) code for six users operating at a bit rate of 60 Gb/s (10×6 Gb/s). Also, an algorithm is designed for EDW code with mapping technique for any weight that can be greater than two. The EDW code is analyzed for bit error rate (BER) and Q-factor using direct detection technique. Further, the system is compared with three dispersion compensating techniques (pre, post and symmetrical). The results indicate that by using symmetrical compensation the maximum usable distance increases to more than twice as compared to without compensation for the targeted BER (10−9), whereas by using p- and post-compensation the BER value increases to 10−13 as compared to without compensation whose BER value is 10−5. The comparison results show acceptable performance improvement. [ABSTRACT FROM AUTHOR]

Considering the growing demand for broadband of access networks, in the present paper we investigate various modulation formats as a way of increasing the performance of optical transmission systems. Non-return-to-zero (NRZ) on-off keying, return-to-zero (RZ) OOK, carrier suppressed RZ (CSRZ) OOK, duobinary (DB), NRZ differential phase shift keying (NRZDPSK), RZDPSK and CSRZ-DPSK formats are compared using the maximal achievable reach with bit error rate less than 10-9 as a criterion. Simulations are performed by using OptSim software tool. It is shown that using the transmission system without dispersion compensation the best results are shown by duobinary and CSRZ-OOK modulation formats, but with the system using dispersion compensating fiber (DCF) the longest transmission distance is achieved by RZDPSK modulation format. By investigating the influence of channel spacing for best-performed modulation formats, network reach decrease for transmission systems with DCF fiber has been observed due to channel crosstalk. [ABSTRACT FROM AUTHOR]

The design of a residual dispersion compensating fiber in an equiangular spiral photonic crystal fiber (ES-PCF) structure is presented in the wavelength range 1350-1650 nm. A step-by-step design optimization is demonstrated and a maximum optimized value of average dispersion - 393 ps/nm km with a flattened dispersion profile with a very high birefringence is reported. It has been found that for the ES-PCF, a very high birefringence of 0.0278 at the wavelength 1550 nm can be obtained by employing an elliptical air hole as defect in the core region. An efficient full-vectorial finite-element method with vector edge element is employed in this study. The proposed ES-PCF can be an excellent candidate to be used in a wavelength-division-multiplexing optical fiber transmission system for residual chromatic dispersion compensation as well as maintaining single polarization. [ABSTRACT FROM PUBLISHER]

We propose and demonstrate a novel type of mix Raman and Erbium Doped Fiber Amplifier (EDFA) to recycle the residual Raman pump for enhancing the gain efficiency of power. The mix amplifier is to implement the residual Raman pump from the Stimulated Raman Scattering (SRS) of Raman fiber amplifier (RFA), to be recycled in the Erbium doped fiber (EDF) as the pump of the Erbium doped fiber amplifier (EDFA) [Dai et al., IEEE Photon Technol Lett 8 (1996), 1713–1715.1]. The proposed mix amplifier system structure has only one pump source for Raman amplification, and residual Raman pump after the Dispersion compensating fiber (DCF) is recycled for erbium doped fiber as the secondary signal amplification. The proposed mix amplifier structure can improve the total gain efficiency by 19.3 dB, compared with the performance of the only one Raman amplifier. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 358–361, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24055 [ABSTRACT FROM AUTHOR]

Dispersion compensating modules (DCM) are key components in long distance and high-speed fiber-optic transmission systems. However, many types of DCMs exhibit multipath interference (MPI) that acts as noise in transmission and degrades the bit error rate of the system. Further, MPI generated in DCMs is mostly due to forward scattering and mostly of the coherent type. This type of MPI cannot be correctly measured using conventional measurement techniques that use electrical spectrum analysis to measure post-detection noise. We demonstrate an accurate and simple method of MPI measurement using a swept wavelength system apparatus. We discuss the strengths and limitations of this measurement method and show system results of Q penalty due to MPI from concatenated DCMs. [ABSTRACT FROM AUTHOR]

We report design optimization of a dual-core dispersion slope compensating fiber (DSCF) for broadband dense wavelength division multiplexing (DWDM) transmission separately in the S-, C-, and L-bands through a 1310 nm-optimized conventional single-mode fiber (CSF). Index profile parameters of the DSCF have been adjusted to simultaneously achieve a mode effective area, which match that of the G.652 fiber as closely as possible in order to contain potentially detrimental nonlinear propagation effects like four-wave mixing and cross-phase modulation (XPM). Theoretical figure of merit of the designed dispersion compensating fiber (DCF) is ∼900 ps/(nm-dB) @ 1550 nm, and its estimated bend loss for a single turn bend diameter of 32 mm is negligible. [Copyright &y& Elsevier]