Abstract
Optical networking technologies can play a significant role in the realization of grid and data centre systems. The new and developing internet applications are progressively becoming high performance and network based, and the performance of these applications are depending on the optical network and cloud computing services. In this chapter, the authors discuss the capabilities of optical transmission and the switching techniques. An AWG-based optical switch is discussed in the chapter and the performance of switch is measured in physical and network layer parameters. Design modifications in the switch is suggested, for improving the performance of switch. The overall performance of switch is also measured when the switch is placed into the network where cascading of two or more switches are required.
TopBackground
In this section a brief background of optical network is presented the various devises which are used in to the core of optical switches is also discussed in this section.
Advantages of Optical Communication
The optical fiber technology is based on the propagation of the optical pulses in optical fiber. Hence, the system offers advantages like large optical bandwidth (theoretically infinite), shock proof immune to interference etc. The advantages of the optical fiber communication can be summarized as (Agrawal, 2012):
- 1.
The optical fiber cable offers a very large bandwidth, it is very light weight, and diameter is very small, hence laying of cable is not a daunting task.
- 2.
The optical fiber cable is non-conductor; hence systems are shock free.
- 3.
The optical fibre systems are immune to Interference and Crosstalk
- 4.
The transmission is very secure and fiber lay down under ground and tapping of the signal is not possible. Thus, it offers very high security of signals.
- 5.
In the region of interest the transmission loss is negligible.
- 6.
The optical fiber communication systems are rugged and very flexible.
- 7.
The optical fiber communication systems are very reliable and maintenance is easy.
Generic Optical Fiber Communication System
In 1960, during his research for US Air force, RAND corporation scientist Paul Baran was the first one to introduce the concept of packet switching in 1960 (Agrawal, 2012). In packet switching, the information is transferred into small size packets. Each packet contains small chunks of data which is to be transmitted between various nodes into network. Inside the network, at each node the packets are either buffered or it can be directly transmitted towards the output port which results into variable queuing delay among packets. This feature makes a difference between circuit and packet switching as in circuit switching a dedicated path is established in advance and continue till communication takes place. For optimizing available network channel capacity, packet switching technologies are used (Agrawal, 2012). By using packet switching, the transmission latency can be minimized (i.e. the time taken by data to pass across the network), and the robustness of network can be increases (Koch, 2012).
Key Terms in this Chapter
RAM: Due to unavailability of optical storage device the RAM is used as the electronic buffer in to the design of switch.
Amplifier: The amplifiers are the devices which are used to amplify the signals when the signal strength goes downs.
Fiber Delay Lines: The fiber delay lines (FDL) are used in the switch for storing the packets in to the optical domain.
AWG: The AWG router is used to map an input waveguide to an array of output waveguides in such a way that the different wavelength signals present in the input waveguide are mapped on the different output waveguides.
BER: As the name implies the bit error rate is defined as the rate at which the error occurs in the transmission medium.
WDM: The wavelength division multiplexing is a technique which modulate the optical carrier signals of varying wavelengths of laser light, onto a single optical fiber.
OPS: In optical networks, it is assumed that the data traverse form one node to another node in a form of fixed size packets are referred as optical packet switching (OPS).