Fiber Optic and Atmospheric Optical Communication

Nathan Blaunstein, Shlomo Engelberg, Evgenii Krouk, Mikhail Sergeev

• Publisher: Wiley-IEEE Press
• Year: 2019
• ISBN:
  9781119602033
• Edition: 1
• Topic: Scienze fisiche
• Subtopic: Onde e meccanica ondulatoria

A GUIDE TO THE FUNDAMENTAL THEORY AND PRACTICE OF OPTICAL COMMUNICATION

Fiber Optic and Atmospheric Optical Communication offers a much needed guide to characterizing and overcoming the drawbacks associated with optical communication links that suffer from various types of fading when optical signals with information traverse these wireless (atmospheric) or wired (fiber optic) channels.

The authors—noted experts on the topic—present material that aids in predicting the capacity, data rate, spectral efficiency, and bit-error-rate associated with a channel that experiences fading. They review modulation techniques and methods of coding and decoding that are useful when implementing communications systems. The book also discusses how to model the channels, including treating distortion due to the various fading phenomena. Light waves and their similarity to radio waves are explored, and the way light propagates through the atmosphere, through materials, and through the boundary between two materials is explained. This important book:

• Characterizes principal optical sources and detectors, including descriptions of their advantages and disadvantages, to show how to design systems from start to finish
• Provides a new method of predicting and dealing with the dispersive properties of fiber optic cables and other optical guiding structures in order to increase data stream capacity
• Highlights effects of material and multimode (multi-ray) dispersion during propagation of optical signals with data through fiber optic channels
• Presents modulation techniques and methods of coding and decoding that are useful when implementing communications systems

Written for professionals dealing with optical and electro-optical communications, Fiber Optic and Atmospheric Optical Communication explores the theory and practice of optical communication both when the optical signal is propagating through the atmosphere and when it is propagating through an optical fiber.

Part I
Optical Communication Link Fundamentals

1
Basic Elements of Optical Communication

1.1 Spectrum of Optical Waves

An optical communication system transmits analog and digital information from one place to another using high carrier frequencies lying in the range of 100–1000 THz in the visible and near‐infrared (IR) region of the electromagnetic spectrum [1–15]. As for microwave systems, they operate at carrier frequencies that are 5 orders of magnitude smaller (∼1–10 GHz).

White light involves the wavelength band from the ultraviolet spectral band, passing the visible one, to the near‐IR band, which has been included here since most fiber communications use carriers in the IR having lowest losses of glass fiber intrinsic surface [8–10].

There are some links in the visible band based on plastic fiber intrinsic surface and therefore having higher loss. Therefore, for the visible optical band such fiber is utilized for short paths. Thus, optical fiber systems operating in 650–670 nm bandwidths with plastic intrinsic surface have loss of 120–160 dB/km, whereas those operating in 800–900 nm bandwidth have loss of 3–5 dB/km, and those operating in 1250–1350 and 1500–1600 nm bandwidth, based on glass surface, have loss of 0.5–0.25 dB/km, respectively.

The relationship between wavelength ( λ ) and frequency (f) is λ = c/f , where the velocity of light in free space is c = 3 · 10⁸ m/s. As an example, a wavelength of λ = 1.5 μm corresponds to a frequency of 2 · 10¹⁴ Hz = 2 · 10² THz (a corresponding period of oscillations is T = 0.5 · 10⁻¹⁴ s).

A sufficiently wide frequency band has allowed an increase in the bit rate–distance product over a period of about 150 years from ∼10² to ∼10¹⁵ bps/km (summarized from Refs. [7,12,14]).

1.2 Optical Communication in Historical Perspective

There are five generations of light communication systems, which differ from each other by wavelength, bit rate (Mbps), and the range of communication between optical terminals [7,12,14].

First Generation:

• started in 1980;
• wavelength is 800 nm;
• bit rate – 45 Mbps (megabit per second);
• optical te...