22-03-2012, 02:17 PM
optical communication
freespace optics full report.doc (Size: 61 KB / Downloads: 27)
INTRODUCTION
When we talk about optical communication, most people think about optical-fiber. But optical communication is also possible without optical-fiber. We know that light travels through air for a lot less money. This makes possible the optical communication without optical-fiber. Optical communication without fiber is known as Free Space Optics. It is used due to economic advantages. Since the introduction of internet the backbone traffic is increasing at the rate greater than 100%, hence the owner of the backbone infrastructure (which is entirely based on fiber optics) are eagerly embracing technologies that add of the capacity of the fiber optics without adding mountains of optical cables.
FSO is not a new idea. 30-years back optical-fiber cables are used for high-speed communication. In those days FSO are used for high-speed connectivity over short distances. Today’s FSO can carry full-duplex data at gigabit-per-second rates over metropolitan distances.
What is Free Space Optics (FSO)?
Free Space Optics (FSO) is a line-of-sight technology that uses lasers to provide optical bandwidth connections. Currently, Free Space Optics are capable of up to 2.5 Gbps of data, voice and video communications through the air, allowing optical connectivity without requiring fiber-optic cable or securing spectrum licenses. Free Space Optics require light, which can be focused by using either light emitting diodes (LEDs) or lasers (light amplification by stimulated emission of radiation). The use of lasers is a simple concept similar to optical transmissions using fiber-optic cables; the only difference is the medium. Light travels through air faster than it does through glass, so it is fair to classify Free Space Optics as optical communications at the speed of light.
HOW FREE SPACE OPTICS (FSO) WORKS
Free Space Optics (FSO) transmits invisible, eye-safe light beams from one "telescope" to another using low power infrared lasers in the teraHertz spectrum. The beams of light in Free Space Optics (FSO) systems are transmitted by laser light focused on highly sensitive photon detector receivers. These receivers are telescopic lenses able to collect the photon stream and transmit digital data containing a mix of Internet messages, video images, radio signals or computer files. Commercially available systems offer capacities in the range of 100 Mbps to 2.5 Gbps, and demonstration systems report data rates as high as 160 Gbps.
FSO: WIRELESS, AT THE SPEED OF LIGHT
Unlike radio and microwave systems, Free Space Optics (FSO) is an optical technology and no spectrum licensing or frequency coordination with other users is required, interference from or to other systems or equipment is not a concern, and the point-to-point laser signal is extremely difficult to intercept, and therefore secure. Data rates comparable to optical fiber transmission can be carried by Free Space Optics (FSO) systems with very low error rates, while the extremely narrow laser beam widths ensure that there is almost no practical limit to the number of separate Free Space Optics (FSO) links that can be installed in a given location.
freespace optics full report.doc (Size: 61 KB / Downloads: 27)
INTRODUCTION
When we talk about optical communication, most people think about optical-fiber. But optical communication is also possible without optical-fiber. We know that light travels through air for a lot less money. This makes possible the optical communication without optical-fiber. Optical communication without fiber is known as Free Space Optics. It is used due to economic advantages. Since the introduction of internet the backbone traffic is increasing at the rate greater than 100%, hence the owner of the backbone infrastructure (which is entirely based on fiber optics) are eagerly embracing technologies that add of the capacity of the fiber optics without adding mountains of optical cables.
FSO is not a new idea. 30-years back optical-fiber cables are used for high-speed communication. In those days FSO are used for high-speed connectivity over short distances. Today’s FSO can carry full-duplex data at gigabit-per-second rates over metropolitan distances.
What is Free Space Optics (FSO)?
Free Space Optics (FSO) is a line-of-sight technology that uses lasers to provide optical bandwidth connections. Currently, Free Space Optics are capable of up to 2.5 Gbps of data, voice and video communications through the air, allowing optical connectivity without requiring fiber-optic cable or securing spectrum licenses. Free Space Optics require light, which can be focused by using either light emitting diodes (LEDs) or lasers (light amplification by stimulated emission of radiation). The use of lasers is a simple concept similar to optical transmissions using fiber-optic cables; the only difference is the medium. Light travels through air faster than it does through glass, so it is fair to classify Free Space Optics as optical communications at the speed of light.
HOW FREE SPACE OPTICS (FSO) WORKS
Free Space Optics (FSO) transmits invisible, eye-safe light beams from one "telescope" to another using low power infrared lasers in the teraHertz spectrum. The beams of light in Free Space Optics (FSO) systems are transmitted by laser light focused on highly sensitive photon detector receivers. These receivers are telescopic lenses able to collect the photon stream and transmit digital data containing a mix of Internet messages, video images, radio signals or computer files. Commercially available systems offer capacities in the range of 100 Mbps to 2.5 Gbps, and demonstration systems report data rates as high as 160 Gbps.
FSO: WIRELESS, AT THE SPEED OF LIGHT
Unlike radio and microwave systems, Free Space Optics (FSO) is an optical technology and no spectrum licensing or frequency coordination with other users is required, interference from or to other systems or equipment is not a concern, and the point-to-point laser signal is extremely difficult to intercept, and therefore secure. Data rates comparable to optical fiber transmission can be carried by Free Space Optics (FSO) systems with very low error rates, while the extremely narrow laser beam widths ensure that there is almost no practical limit to the number of separate Free Space Optics (FSO) links that can be installed in a given location.