Free Space Optical Communication – Ever Wondered what this is about?

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The term “Free Space Optical Communication” is an Optical Communication technology which involves in communication using Light as the source and can be done by electronic Devices. An optical communication system uses a transmitter, which encodes a message into an optical signal, a channel, which carries the signal to its destination, and a receiver, which reproduces the message from the received optical signal.
The major difference between a Normal Optical communication and Free Space Optical Communication is that in free space communication, light propagating in free space(Air,vacuum) is used to wirelessly transmit data for telecommunications or computer networking.
Free-space point-to-point optical links can be implemented using infrared laser light, although low-data-rate communication over short distances is possible using LEDs. Infrared Data Association (IrDA) technology is a very simple form of free-space optical communications. Free-space optics are additionally used for communications between spacecraft. Maximum range for terrestrial links is of the order of 2 to 3 km (1.2 to 1.9 mi),[4] but the stability and quality of the link is highly dependent on atmospheric factors such as rain, fog, dust and heat.
Researchers used a white LED-based space lighting system for indoor local area network (LAN) communications.A low-cost white LED (GaN-phosphor) which could be used for space lighting can typically be modulated up to 20 MHz.Data rates of over 100 Mbit/s can be easily achieved using efficient modulation schemes and Siemens claimed to have achieved over 500 Mbit/s in 2010.

RONJA_System_Overview
Overview of Free Space Optical Communication

APPLICATIONS:

  • LAN-to-LAN connections on campuses at Fast Ethernet or Gigabit Ethernet speeds
  • LAN-to-LAN connections in a city, a metropolitan area network
  • To cross a public road or other barriers which the sender and receiver do not own
    Speedy service delivery of high-bandwidth access to optical fiber networks
  • Converged Voice-Data-Connection
  • Temporary network installation (for events or other purposes)
  • Reestablish high-speed connection quickly (disaster recovery)
  • As an alternative or upgrade add-on to existing wireless technologies
  • Especially powerful in combination with auto aiming systems, this way you could power moving cars or you can power your laptop while you move or use auto-aiming nodes to create a network with other nodes.
  • As a safety add-on for important fiber connections (redundancy)
  • For communications between spacecraft, including elements of a satellite constellation
  • For inter- and intra -chip communication.

BEST EXAMPLE FOR FREE SPACE OPTICAL COMMUNICATION:
RONJA (Reasonable Optical Near Joint Access) is a free-space optical communication system originating in the Czech Republic. It transmits data wirelessly using beams of light. Ronja can be used to create a 10 Mbit/s full duplex Ethernet point-to-point link. Estimated 1000 to 2000 links were built worldwide The range of the basic configuration is 1.4 km (0.87 mi). The device consists of a receiver and transmitter pipe (optical head) mounted on a sturdy adjustable holder. Two coaxial cables are used to connect the rooftop installation with a protocol translator installed in the house near a computer or switch. The range can be extended to 1.9 km (1.2 mi) by doubling or tripling the transmitter pipe..