This book presents new frontiers in data communication. To transcend the physical limitations of current optical communication technologies, totally new multiplexing schemes beyond TDM/WDM, novel transmission optical fibers handling well above Pbit/s capacity, and next-generation optical submarine cable systems will need to be developed. The book offers researchers working at the forefront, as well as advanced Ph.D. students in the area of optical fiber communications systems and related fields, an essential guide to state-of-the-art optical transmission technologies. It explores promising new technologies for the exabit era; namely, the three “M technologies”: multi-level modulation, multi-core fiber, and multi-mode control.

At the beginning of an exciting new era in optical communications, we review fundamentals as well as practical experimental aspects of MIMO-SDM: we discuss the importance of selectively addressing all modes of a coupled-mode SDM channel at transmitter and receiver in order to achieve reliable capacity gains and show that reasonable levels of mode-dependent loss (MDL) are acceptable without much loss of channel capacity. We then introduce MIMO-DSP techniques as an extension of familiar algorithms used in polarization-division multiplexed (PDM) digital coherent receivers and discuss their functionality and scalability. Finally, we review the design of mode multiplexers (MMUXs) that allow for the mapping of the individual transmission signals onto an orthogonal basis of waveguide mode, and discuss their performance in experimental demonstrations.

Wavelength-division multiplexing (WDM) enables multiple communication links to use a common transmission fiber by transmitting a multitude of different wavelengths at the same time. This chapter describes WDM technology, including options such as coarse and dense WDM defined by standards such as ITU-T Recommendations G.652 to G.657. The wavelength spectrum allocation for the L-, C-, S-, E-, and O-bands is discussed. Related technologies, such as time-division multiplexing and erbium-doped fiber amplifiers, are also described in this context. Topics include service mapping using the generic framing procedure and virtual concatenation, technology for optical transceivers and filters, reconfigurable optical add/drop multiplexers, fiber Bragg gratings, and array waveguides. WDM link budgets and noise sources are also discussed, including rings and other topologies, protection schemes, dispersion compensating fiber, equalization, and modulation options including extensions to 100G.

Optical fiber communication has emerged as a high potential substitute for communication methods such as twisted pair and coaxial wire. The main advantage of optical fiber over previous methods is to have higher capacity of data rate transmission. The conventional types of modulation and demodulation technique, which have been used through optical fiber communication system are Wavelength Division Multiplexing (WDM) technique and Dense Wavelength Division Multiplexing (DWDM) technique so far.

This chapter gives an overview of design and optimization of few-mode optical fibers (FMF) for space-division multiplexed transmission. The design criteria are outlined, along with performance limitations of the traditional step-profile and graded-index profiles. The trade-offs between number of usable optical modes (related to total channel capacity), differential group delay, differential mode attenuation, mode coupling, and the impact on MIMO (multiple-input and multiple-output) receiver complexity are outlined. Improved fiber designs are analyzed which maximize channel capacity with foreseeable next-generation receiver technology. FMF measurement technology is overviewed.

Results of workshop on optical communication systems for space applications.

In order to adapt to the ever-increasing demands of telecommunication needs, today’s network operators are implementing 100 Gb/s per dense wavelength division multiplexing (DWDM) channel transmission. At those data rates, the performance of fiberoptic communication systems is degraded significantly due to intra- and inter-channel fiber nonlinearities, polarization-mode dispersion (PMD), and chromatic dispersion. In order to deal with those channel impairments, novel advanced techniques in modulation and detection, coding and signal processing are needed. This unique book represents a coherent and comprehensive introduction to the fundamentals of optical communications, signal processing and coding for optical channels. It is the first to integrate the fundamentals of coding theory with the fundamentals of optical communication.