Bit Error Rate Optimization in Fiber Optic …

1 International Journal of Machine Learning and Computing, Vol. 1, No. 5, December 2011. Bit Error Rate Optimization in Fiber Optic Communications S. M. Jahangir Alam, M. Rabiul Alam, Guoqing Hu, and Md. Zakirul Mehrab The approximation is accurate for a long studied time interval Abstract In telecommunication, the Bit Error Rate (BER) is and a high number of bit errors . an indication of how often data has to be retransmitted because of an Error . The different modulation techniques scheme is suggested for improvement of BER in Fiber Optic communications.

2 The developed scheme has been tested on II. BIT Error RATE AND SIGNAL-TO- noise RATIO. optical Fiber systems operating with a non-return-to-zero (NRZ). format at transmission rates of up to 10 Gbps. Performance of A. Bit Error Rate improved detected signals has been evaluated by the analysis of In telecommunication transmission, the bit Error rate (BER). quality factor and computed BER. Numerical simulations have is the percentage of bits that have errors relative to the total shown a noticeable improvement of the system BER after number of bits received in a transmission.

3 For example, a implementation of the suggested processing operation on the detected electrical signals at central wavelengths in the region of transmission might have a BER of 10-6, meaning that, out of 1310 nm. 1,000,000 bits transmitted, one bit was in Error . The BER is an indication of how often data has to be retransmitted Index Terms BER improvement, Modulation Techniques, because of an Error . Too high a BER may indicate that a noise , Optimization , NRZ. slower data rate would actually improve overall transmission time for a given amount of transmitted data since the BER.

4 Might be reduced, lowering the number of packets that had to I. INTRODUCTION be present. The BER may be improved by choosing a strong Optical fibers are widely used in Fiber Optic signal strength (unless this causes cross-talk and more bit communications which permits transmission over longer errors ), by choosing a slow and robust modulation scheme or distances and at higher bandwidths than other forms of line coding scheme, and by applying channel coding schemes communication. Optical transmission networks based on such as redundant forward Error correction codes [1].

5 The wavelength division multiplexing (WDM) architecture is transmission BER is the number of detected bits that are dominating the all optical data transportation with bit rates incorrect before Error correction, divided by the total number exceeding several terabit per second rates to serve the ever of transferred bits (including redundant Error codes). increasing demand of Internet Protocol (IP) networks. Some Normally the transmission BER is larger than the information of the main TCP/IP networking functions such as routing, BER.

6 The information BER is affected by the strength of the add-drop multiplexing and demultiplexing and wavelength forward Error correction code. conversion, need to be functional to encapsulate the IP packet B. Signal-To- noise Ratio requirements into the optical layer. The linear as well as the nonlinear characteristics of the optical Fiber at higher bit rates , Signal-to- noise ratio (often abbreviated SNR or S/N) is a seriously limit the data transmission performance and it is measure used in science and engineering to quantify how therefore becoming necessary to develop approaches to much a signal has been corrupted by noise .

7 It is defined as the improve regeneration of transmitted data. Experimental ratio of signal power to the noise power corrupting the signal. investigations have shown a considerable progress in this A ratio higher than 1:1 indicates more signal than noise . direction. These were based on compensation techniques, While SNR is commonly quoted for electrical signals, it can filtering, developing optimized line coding, and further be applied to any form of signal (such as isotope levels in an dispensation of received signal.)

8 In a communication system, ice core or biochemical signaling between cells). In less the receiver side BER may be affected by transmission technical terms, signal-to- noise ratio compares the level of a channel noise , interference, distortion, bit synchronization desired signal (such as music) to the level of background problems, attenuation, wireless multipath fading, etc. The noise . The higher the ratio, the less obtrusive the background BER can be considered as an approximate estimate of the bit noise is. Signal-to- noise ratio is sometimes used informally to Error probability which is the expectation value of the BER.

9 Refer to the ratio of useful information to false or irrelevant data in a conversation or exchange. For example, in online discussion forums and other online communities, off-topic Manuscript received September 13, 2011, revised October 31, 2011 posts and spam are regarded as " noise " that interferes with S. M. Jahangir Alam and Guoqing Hu are with the Department of the "signal" of appropriate discussion. The concepts of Mechanical and Electrical Engineering, Xiamen University, China (e-mail: signal-to- noise ratio and dynamic range are closely related.)

10 Jahangir_uits@ ; M. Rabiul Alam is with the School of Computer Science and Engineering, Dynamic range measures the ratio between the greatest University of Information Technology and Sciences, Dkaka, Bangladesh undistorted signal on a channel and the smallest detectable (e-mail: alam2007@ ). signal, which for most purposes is the noise level. Md. Zakirul Mehrab is with the Spark Bangladesh Ltd., Dkaka, Signal-to- noise ratio measures the ratio between an arbitrary Bangladesh (e-mail: 435. International Journal of Machine Learning and Computing, Vol.)