page_title: Wireless
section_title: Free-space optical
hierarchical_section_title: Wireless / Modes / Free-space optical
caption_attribution_description: English: An 8-beam free space optics laser link, rated for 1Gbps at a distance of approximately 2km. The receptor is the large lens in the middle, the transmitters the smaller ones. To the top and right side a monocular for assisting the alignment of the two heads. Picture has been edited to remove distracting surrounding objects. Français&#160;: Émetteur-récepteur laser à huit rayons, pouvant transmettre de l'information à 1Gbps sur une distance de 2km. Le récepteur est le grand disque au centre, les émetteurs sont les disques plus petits qui l'entourent. En haut à gauche, on distingue une lunette de visée qui aide à l'alignement de l'appareil.
context_page_description: Wireless communication is the electromagnetic transfer of information between two or more points that are not connected by an electrical conductor. The most common wireless technologies use radio waves. With radio waves, intended distances can be short, such as a few meters for Bluetooth or as far as millions of kilometers for deep-space radio communications. It encompasses various types of fixed, mobile, and portable applications, including two-way radios, cellular telephones, personal digital assistants, and wireless networking. Other examples of applications of radio wireless technology include GPS units, garage door openers, wireless computer mouse, keyboards and headsets, headphones, radio receivers, satellite television, broadcast television and cordless telephones. Somewhat less common methods of achieving wireless communications include the use of other electromagnetic wireless technologies, such as light, magnetic, or electric fields or the use of sound.
  The term wireless has been used twice in communications history, with slightly different meaning.
context_section_description: Free-space optical communication (FSO) is an optical communication technology that uses light propagating in free space to transmit wirelessly data for telecommunications or computer networking. "Free space" means the light beams travel through the open air or outer space. This contrasts with other communication technologies that use light beams traveling through transmission lines such as optical fiber or dielectric "light pipes".
  The technology is useful where physical connections are impractical due to high costs or other considerations. For example, free space optical links are used in cities between office buildings which are not wired for networking, where the cost of running cable through the building and under the street would be prohibitive. Another widely used example is consumer IR devices such as remote controls and IrDA (Infrared Data Association) networking, which is used as an alternative to WiFi networking to allow laptops, PDAs, printers, and digital cameras to exchange data.
caption: An 8-beam free space optics laser link, rated for 1 Gbit/s at a distance of approximately 2 km. The receptor is the large disc in the middle, the transmitters the smaller ones. To the top and right corner a monocular for assisting the alignment of the two heads.
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