Digital Equalization in Coherent Optical Transmission Systems

Zhou, Xiang; Xie, Chongjin

doi:10.1002/9781119078289.ch8

Cited by 5 publications

(4 citation statements)

References 24 publications

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“…From then on, DSP rapidly enabled the third era of digital-coherent systems [36], [37], [38], [39], [40], [41], [42], [43]. The concept of digitally coherent optical receivers dates back to the early 1990s [44] and is, today, almost exclusively used by high-speed optical transmission systems exceeding a reach of ∼100 km.…”

Section: H I S T O R I C a L P E R S P E C T I V Ementioning

confidence: 99%

The Role of Parallelism in the Evolution of Optical Fiber Communication Systems

2022

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Section: H I S T O R I C a L P E R S P E C T I V Ementioning

confidence: 99%

The Role of Parallelism in the Evolution of Optical Fiber Communication Systems

2022

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“…(10) presents a number of issues for digital implementation, not only it is infinite in duration but since it passes all frequencies for a finite sampling frequency, aliasing will occur. These problems can be solved by truncating the impulse response to a finite duration which can be express for sampling time Ts as [7,28]:…”

Section: ) Time Domain Equalizermentioning

confidence: 99%

“…In an adaptive equalizer, we frequently have a cost function whose gradient is stochastically estimated and used to update the tap weights. For details of underlying mathematics for such estimation, readers are refer to [28]. While enormous algorithms for filter tap adaption is available in signal processing literatures, herein we discuss the commonly used algorithms used in coherent optical systems.…”

Section: A Adaptation Algorithmsmentioning

confidence: 99%

Digital Signal Processing for Coherent Transceivers Employing Multilevel Formats

Faruk

Savory

2017

J. Lightwave Technol.

215

115

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Digital coherent transceivers have revolutionized optical fiber communications due to their superior performance offered compared to intensity modulation and direct detection based alternatives. As systems employing digital coherent transceivers seek to approach their information theoretic capacity, the use of multilevel modulation formats combined with appropriate forward error correction becomes essential. Given this context, in this tutorial paper, we therefore explore the digital signal processing (DSP) utilized in a coherent transceiver with a focus on multilevel modulation formats. By way of an introduction, we open by discussing the photonic technology required to realize a coherent transceiver. After discussing this interface between the analog optical channel and the digital domain, the rest of the paper is focused on DSP. We begin by discussing algorithms that correct for imperfections in the optical to digital conversion, including IQ imbalance and timing skew. Next, we discuss channel equalization including means for their realization for both quasi-static and dynamic channel impairments. Synchronization algorithms that correct for the difference between the transmitter and receiver oscillators both optical and electrical are then discussed and issues associated with symbol decoding highlighted. For most of the cases, we start with polarization division multiplexed quadrature phase-shift keying (PDM-QPSK) format as a basis and then discuss the extension to allow for high order multilevel formats. Finally, we conclude by discussing some of the open research challenges in the field.

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“…Using coherent detection, the powerful compensation of transmission impairments can be implemented in electrical domain. With the full information of the received signals, the chromatic dispersion, the polarization mode dispersion, the carrier phase noise and the fiber Kerr nonlinearities can be equalized and mitigated using digital signal processing (DSP) [11][12][13][14][15][16][17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Digital Signal Processing for Optical Communications and Networks

Xu¹

2017

Optical Fiber and Wireless Communications

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T h ea c h i e v a b l ei n f o r m a t i o nr a t e so fo p t i c a lcommunication networks have been widelyincreased over the past four decades with the introduction and development of optical amplifiers, coherent detection, advanced modulation formats, and digital signal processing techniques. These developments promoted the revolution of optical communication systems and the growth of Internet, towards the direction of high-capacity and long-distance transmissions. The performance of long-haul high-capacity optical fiber communication systems is significantly degraded by transmission impairments, such as chromatic dispersion, polarization mode dispersion, laser phase noise and Kerr fiber nonlinearities. With the entire capture of the amplitude and phase of the signals using coherent optical detection, the powerful compensation and effective mitigation of the transmission impairments can be implemented using the digital signal processing in electrical domain. This becomes one of the most promising techniques for next-generation optical communication networks to achieve a performance close to the Shannon capacity limit. This chapter will focus on the introduction and investigation of digital signal processing employed for channel impairments compensation based on the coherent detection of optical signals, to provide a roadmap for the design and implementation of real-time optical fiber communication systems.

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Digital Equalization in Coherent Optical Transmission Systems

Cited by 5 publications

References 24 publications

The Role of Parallelism in the Evolution of Optical Fiber Communication Systems

The Role of Parallelism in the Evolution of Optical Fiber Communication Systems

Digital Signal Processing for Coherent Transceivers Employing Multilevel Formats

Digital Signal Processing for Optical Communications and Networks

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