*Structured Light Fields in Optical Fibers DOI: http://dx.doi.org/10.5772/intechopen.85958*

*Fiber Optics - From Fundamentals to Industrial Applications*

*Wavelength division multiplexing (https://www.newport.com/t/fiber-optic-basics).*

*Time division multiplexing (https://www.newport.com/t/fiber-optic-basics).*

As per the data on the Newport website, the ITU (International

onto a single carrier by increasing the modulation rate, and each channel is allotted

Telecommunication Union) had proposed a set of closely spaced wavelengths in the 1550 nm window. This method of WDM is known as Dense Wavelength Division Multiplexing or DWDM. These different wavelengths or channels, spaced 100 GHz apart or 0.8 nm approximately, form the ITU-T grid. The 1550 nm window has the smallest amount of attenuation and lies in the band in which erbium-doped optical amplifiers operate. DWDM systems have a fixed starting and a distinct ending point. Thus, these are, therefore, called point-to-point links. Research is being done to make these networks evolve into completely configurable networks that are not

Transparency in the optical layer opens many possibilities for the future. Digital and analog transmission can occur on the same fiber. Different bit rates using different protocols will all travel together. Current research is being performed on reconfiguring an optical network in real time. Wavelength selective switching allows wavelengths to be routed through the network individually. Some of the applications of this are for network restoration and redundancy, which may reduce or entirely eliminate the need for an entire back up system to help the network recover from failures such as equipment malfunctions or fiber breaks. A reconfigurable network may offer bandwidth on demand to configure itself to optimize for traffic bottlenecks. The future may also include wavelength translation to convert traffic on one wavelength to another wavelength in the

The second method is known as wavelength division multiplexing or WDM. Using this method, capacity can be increased by using more than one optical carrier (wavelength) in a single fiber. Therefore, adding a second transmitter and receiver to an optical fiber can double the bandwidth of that communications system (**Figure 10**).

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optical domain.

**Figure 10.**

**Figure 9.**

a time slot (**Figure 9**).

limited to fixed point-to-point links.

All optical switching is still in the research phase; however, researchers are looking for ways to create reliable, low loss switches with fast switching speeds. Investigation into the possibility of optical packet switching and other novel technologies is currently underway. The all-optical network may be just around the corner.

The future is fiber-optic technology, and the network is growing exponentially worldwide. Most major companies are already using fiber-optic systems in their backbone applications. These systems offer higher reliability and speed.
