scholarly journals Advanced DSP for Coherent Optical Fiber Communication

2019 ◽  
Vol 9 (19) ◽  
pp. 4192 ◽  
Author(s):  
Jian Zhao ◽  
Yaping Liu ◽  
Tianhua Xu
Keyword(s):  
Optical Fiber ◽  
Optical Transmission ◽  
High Capacity ◽  
Single Mode ◽  
Optical Fiber Communication ◽  
Coherent Detection ◽  
System Capacity ◽  
Limiting Factors ◽  
Transmission Systems ◽  
Fiber Communication

In this paper, we provide an overview of recent progress on advanced digital signal processing (DSP) techniques for high-capacity long-haul coherent optical fiber transmission systems. Not only the linear impairments existing in optical transmission links need to be compensated, but also, the nonlinear impairments require proper algorithms for mitigation because they become major limiting factors for long-haul large-capacity optical transmission systems. Besides the time domain equalization (TDE), the frequency domain equalization (FDE) DSP also provides a similar performance, with a much-reduced computational complexity. Advanced DSP also plays an important role for the realization of space division multiplexing (SDM). SDM techniques have been developed recently to enhance the system capacity by at least one order of magnitude. Some impressive results have been reported and have outperformed the nonlinear Shannon limit of the single-mode fiber (SMF). SDM introduces the space dimension to the optical fiber communication. The few-mode fiber (FMF) and multi-core fiber (MCF) have been manufactured for novel multiplexing techniques such as mode-division multiplexing (MDM) and multi-core multiplexing (MCM). Each mode or core can be considered as an independent degree of freedom, but unfortunately, signals will suffer serious coupling during the propagation. Multi-input–multi-output (MIMO) DSP can equalize the signal coupling and makes SDM transmission feasible. The machine learning (ML) technique has attracted worldwide attention and has been explored for advanced DSP. In this paper, we firstly introduce the principle and scheme of coherent detection to explain why the DSP techniques can compensate for transmission impairments. Then corresponding technologies related to the DSP, such as nonlinearity compensation, FDE, SDM and ML will be discussed. Relevant techniques will be analyzed, and representational results and experimental verifications will be demonstrated. In the end, a brief conclusion and perspective will be provided.

scholarly journals Comparison between Direct and Coherent Optical Communication System

2011 ◽  
Vol 8 (2) ◽  
pp. 479-484
Author(s):  
Baghdad Science Journal
Keyword(s):  
Optical Fiber ◽  
Communication System ◽  
Direct Detection ◽  
Optical Fiber Communication ◽  
Optical Signal ◽  
Coherent Detection ◽  
Laser Source ◽  
System Quality ◽  
Fiber Communication ◽  
Optical Fiber Communication System

The work in this paper focuses on the system quality of direct and coherent communication system for two computers. A system quality is represented by Signal to Noise ratio (SNR) and Bit Error Rate (BER). First part of the work includes implementation of direct optical fiber communication system and measure the system quality .The second part of the work include implementation both the( homodyne and heterodyne)coherent optical fiber communication system and measure the system quality . Laser diode 1310 nm wavelength with its drive circuit used in the transmitter circuit . A single mode of 62.11 km optical fiber is selected as transmission medium . A PIN photo detector is used in the receiver circuit. The optical D-coupler was used to combine the optical signal that come from transmitter laser source with optical signal of laser local oscillator at 1310/1550 nm to obtain coherent detection . Results show that for direct detection the SNR and the BER (28.5 dB, 9.64x10-8,) respectively, while for homodyne and heterodyne coherent detection , the SNR(94.36,97.71)dB and the BER are (1.32x10-22,2.43x10-23) at maximum optical fiber length at 62.11 km. Results show that the homodyne and heterodyne detection are better than direct detection because the large output SNR and low BER of the received signal.

scholarly journals Coded Modulation and Impairment Compensation Techniques in Optical Fiber Communication

2021 ◽  
Author(s):  
Zhipei Li ◽  
Dong Guo ◽  
Ran Gao
Keyword(s):  
Optical Fiber ◽  
Communication Systems ◽  
High Speed ◽  
Transmission Rate ◽  
Optical Fiber Communication ◽  
Coded Modulation ◽  
Coherent Detection ◽  
Modulation Scheme ◽  
Fiber Communication ◽  
Modulation Format

This chapter deals with coded modulation and impairment compensation techniques in optical fiber communication. Probabilistic shaping is a new coded modulation technology, which can reduce transmission power by precoding, reduce bit error rate and improve communication rate. We proposed a probabilistic shaping 16QAM modulation scheme based on trellis coded modulation. Experimental results show that this scheme can achieve better optical SNR gain and BER performance. On the other hand, in order to meet the demand of transmission rate of next generation high speed optical communication systems, multi-dimensional modulation and coherent detection are sufficiently applied. The imperfect characteristics of optoelectronic devices and fiber link bring serious impairments to the high baud-rate and high order modulation format signal, causes of performance impairment are analyzed, pre-compensation and receiver side’s DSP techniques designed for coherent systems are introduced.

scholarly journals Furtherance in Splicing Technique of Optical Fiber Communication

2020 ◽  
Vol 9 (3) ◽  
pp. 3505-3609
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
High Speed ◽  
Single Mode ◽  
Optical Fiber Communication ◽  
Communication Line ◽  
Long Distance ◽  
Fiber Communication ◽  
Splice Loss ◽  
Distance Communication

The improvement in technology over long distance communication using optical fiber has been regulated over past few decades, and it took drastic enhancement in one of the major parameter for joining two OFC cable (splicing). The different experiments performed in order to bring about the result that can give nearly 0dB splice loss when there is shifting of entire set up of Optical Fiber Communication. The splicing loss is created by the joining of two SMF using fiber optic fusion splicing. The objective of this paper is to determine the low splice loss in joining two single mode or multimode optical fiber, such that long distance communication that required multiple infrastructure assembly for its operational unit can be made relocatable as there is large investment and material and electronic circuitry is associated to it. Therefore to reduce that cost we have sets of analysis that splicing loss can be reduced to 0dB for SMFSMF end face connection or at least no improvement in splice losses while relocation of OFC infrastructure from one place to other place as the result of the tested experiment. Based on experiment conducted we came to conclusion that with essential requirements for establishing a low-loss and high-speed communication line using optical fibers, the need for quality of splicing technology along with perfect core alignment angle is required to reduce splice loss, such that the infrastructure can be shifted to many different location without any additional cost of new material and new resources. The exact measurement of splice loss can be insured by another set of formula which we came across during the experimental performance.

Backbone Optical Fiber Analysis at 1310 nm and 1550 nm

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Nandhakumar P ◽  
Arun Kumar
Keyword(s):  
Optical Fiber ◽  
Real Time ◽  
Optical Fibers ◽  
Single Mode ◽  
Optical Fiber Communication ◽  
Long Distance ◽  
Fiber Communication ◽  
The Real ◽  
Optical Time Domain Reflectometer ◽  
Optic Communication

AbstractOptical fiber communication is the backbone of the entire telecommunication industries in the world. In this work, the real-time backbone long-distance optical fibers (single mode) are tested and analyzed with two different wavelengths (1,310 nm and 1,550 nm) with the help of optical time domain reflectometer. Using these two different wavelengths, how the losses and events of the backbone optical fibers are changing are compared and analyzed. This work will give a way to study the nature of long-distance backbone optical fiber and understand the real-time application of the fiber optic communication.

scholarly journals ANALISIS REDAMANTERHADAP PERFORMANCEDENSE WAVELENGTH DIVISION MULTIPLEXING (DWDM)PADA SISTEM KOMUNIKASI SERAT OPTIKDENGAN METODE LINK POWER BUDGET DI PT. TELKOM PADANG (STUDI KASUS LINK PADANG – LUBUK BASUNG)

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Farta Wendy Herdianta ◽  
Hanesman Hanesman ◽  
Delsina Faiza
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Wavelength Division Multiplexing ◽  
Power Output ◽  
Communication Systems ◽  
Single Mode ◽  
Optical Fiber Communication ◽  
Power Budget ◽  
Fiber Communication ◽  
The Core

The research was conducted by analyzing the optical fiber attenuation of the DWDM performance in terms of power received on optical fiber communication systems link Padang-Lubuk cone in PT. Telkom Padang. Optical fiber has a very small damping. Therefore optical fibers become the primary choice in telecommunications networks. To improve the transmission quality is better then the use of DWDM technology, DWDM technology is a method to insert a number of channels were transmitted in a single optical fiber. Instruments in this study is the Power Meter and OTDR JDSU MTS-2000 type, the type of cable used G.655 Single Mode type. Link Power Budget method is used to determine the performance of DWDM caused by attenuation based on the value of the received power output receiver. On the link Padang - Lubuk cone highest attenuation occurs in core 1 of 29.742dB with 100.035 km cable lengths, and the core 10 of 31.8 dB with 119.998 km cablelengths. Based on the large fault or attenuation/km core 1 of 0.297 dB/km, the core 10 of 0.265 dB/km and the standard ITU-T was 0.35 dB/km. Value attenuation/km core 1 and core 10 is still in normal conditions and under standard ITU-T 0.35 dB/km. Based on optical fiber attenuation, the results of analysis of the link power budget is the value of Rx is smaller than the value of Rx sensitivity of -27 dBm, it can be said performance DWDM optical fiber communication systems in normal and can be used to operate because the power output can still be accepted by receiver in the device. Keywords:optical fiber cable, optical fiber attenuation, DWDM, link power budget.

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