O'Reilly logo

Fiber Optic Communications: Fundamentals and Applications by Shiva Kumar, M. Deen

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Chapter 9Channel Multiplexing Techniques

9.1 Introduction

Typically, the single-channel symbol rates range from 10 Gsym/s to 40 Gsym/s. A symbol rate beyond 40 Gsym/s is hard to achieve in practice because of the speed of electronic components in transmitter and receiver circuits. In the low-loss region of the fiber (1530–1620 nm), it has a bandwidth greater than 10 THz. To utilize the full bandwidth of the fiber, several channels can be multiplexed and they can share the same fiber channel. An EDFA operating in C-band (1530–1565 nm) has a bandwidth of about 4.3 THz and, therefore, several channels can be amplified simultaneously by a single amplifier. The multiplexing techniques can be divided into three types: (i) polarization division multiplexing (PDM) or polarization multiplexing (PM), (ii) frequency or wavelength-division multiplexing (WDM), (iii) time-division multiplexing (TDM).

9.2 Polarization-Division Multiplexing

PDM is an effective technique to double the capacity. Commercial coherent systems make use of PDM and WDM to enhance the capacity. A single-mode fiber supports two polarization modes–one with the electric field aligned with the c09-math-0001-axis and the other aligned with the c09-math-0002-axis (see Section 2.7.5). Therefore, it is possible to transmit information using each of these ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required