OPTICAL FIBRE

Introduction

            Free Space Optics (FSO) communications, also called Free Space Photonics (FSP) or Optical Wireless, refers to the transmission of modulated visible or infrared (IR) beams through the atmosphere to obtain optical communications. Like fiber, Free Space Optics (FSO) uses lasers to transmit data, but instead of enclosing the data stream in a glass fiber, it is transmitted through the air. Free Space Optics (FSO) works on the same basic principle as Infrared television remote controls, wireless keyboards or wireless Palm® devices.

Free Space optics (fso) technology

            Lasers are one of the most significant inventions of the 20th century - they can be found in many modern products, from CD players to fiber-optic networks. The word laser is actually an acronym for Light Amplification by Stimulated Emiission of Radiation. Although stimulated emission was first predicted by Albert Einstein near the beginning of the 20th century, the first working laser was not demonstrated until 1960 when Theodore Maiman did so using a ruby. Maiman's laser was predated by the maser - another acronym, this time for Microwave Amplification by Stimulated Emission of Radiation. A maser is very similar to a laser except the photons generated by a maser are of a longer wavelength outside the visible and/or infrared spectrum.

            A laser generates light, either visible or infrared, through a process known as stimulated emission. To understand stimulated emission, understanding two basic concepts is necessary. The first is absorption which occurs when an atom absorbs energy or photons. The second is emission which occurs when an atom emits photons. Emission occurs when an atom is in an excited or high energy state and returns to a stable or ground state – when this occurs naturally it is called spontaneous emission because no outside trigger is required. Stimulated emission occurs when an already excited atom is bombarded by yet another photon causing it to release that photon along with the photon which previously excited it. Photons are particles, or more properly quanta, of light and a light beam is made up of what can be thought of as a stream of photons. 

Free Space Optics (FSO) or Optical Wireless, refers to the transmission of modulated visible or infrared (IR) beams through the air to obtain optical communications. Like fiber, Free Space Optics (FSO) uses lasers to transmit data, but instead of enclosing the data stream in a glass fiber, it is transmitted through the air. It is a secure, cost-effective alternative to other wireless connectivity options. This form of delivering communication has a lot of compelling advantages.

            Data rates comparable to fiber transmission can be carried with very low error rates, while the extremely narrow laser beam widths ensure that it is possible to co-locate multiple tranceivers without risk of mutual interference in a given location. FSO has roles to play as primary access madium and backup technology. It could also be the solution for high speed residential access. Though this technology sprang into being, its applications are wide and many. It indeed is the technology of the future...