Fiber-optic communication

Fiber-optic communication is a method of transmitting information from one place to another by sending pulses of infrared light through an optical fiber. The light forms an electromagnetic carrier wave, modulated to carry information. Fiber is preferred over electrical cabling when high bandwidth, long distance, or immunity to electromagnetic interference are required; this type of communication can transmit voice and telemetry through local area networks, computer networks, or across long distances. Optical fiber is used by many telecommunications companies to transmit telephone signals, Internet communication, cable television signals. Researchers at Bell Labs have reached internet speeds of over 100 petabit×kilometer per second using fiber-optic communication. First developed in the 1970s, fiber-optics have revolutionized the telecommunications industry and have played a major role in the advent of the Information Age; because of its advantages over electrical transmission, optical fibers have replaced copper wire communications in core networks in the developed world.

The process of communicating using fiber-optics involves the following basic steps: creating the optical signal involving the use of a transmitter from an electrical signal relaying the signal along the fiber, ensuring that the signal does not become too distorted or weak receiving the optical signal converting it into an electrical signal Optical fiber is used by many telecommunications companies to transmit telephone signals, Internet communication and cable television signals. It is used in a multitude of other industries, including medical, defense/government, for data storage, industrial/commercial. In addition to serving the purposes of telecommunications, it is used as light guides, for imaging tools, hydrophones for seismic waves, SONAR, as sensors to measure pressure and temperature. Due to much lower attenuation and interference, optical fiber has large advantages over existing copper wire in long-distance, high-demand applications. However, infrastructure development within cities was difficult and time-consuming, fiber-optic systems were complex and expensive to install and operate.

Due to these difficulties, fiber-optic communication systems have been installed in long-distance applications, where they can be used to their full transmission capacity, offsetting the increased cost. The prices of fiber-optic communications have dropped since 2000; the price for rolling out fiber to homes has become more cost-effective than that of rolling out a copper based network. Prices have dropped to $850 per subscriber in the US and lower in countries like The Netherlands, where digging costs are low and housing density is high. Since 1990, when optical-amplification systems became commercially available, the telecommunications industry has laid a vast network of intercity and transoceanic fiber communication lines. By 2002, an intercontinental network of 250,000 km of submarine communications cable with a capacity of 2.56 Tb/s was completed, although specific network capacities are privileged information, telecommunications investment reports indicate that network capacity has increased since 2004.

In 1880 Alexander Graham Bell and his assistant Charles Sumner Tainter created a early precursor to fiber-optic communications, the Photophone, at Bell's newly established Volta Laboratory in Washington, D. C. Bell considered it his most important invention; the device allowed for the transmission of sound on a beam of light. On June 3, 1880, Bell conducted the world's first wireless telephone transmission between two buildings, some 213 meters apart. Due to its use of an atmospheric transmission medium, the Photophone would not prove practical until advances in laser and optical fiber technologies permitted the secure transport of light; the Photophone's first practical use came in military communication systems many decades later. In 1954 Harold Hopkins and Narinder Singh Kapany showed that rolled fiber glass allowed light to be transmitted, it was considered that the light can traverse in only straight medium. Jun-ichi Nishizawa, a Japanese scientist at Tohoku University, proposed the use of optical fibers for communications in 1963.

Nishizawa invented the PIN diode and the static induction transistor, both of which contributed to the development of optical fiber communications. In 1966 Charles K. Kao and George Hockham at STC Laboratories showed that the losses of 1,000 dB/km in existing glass were due to contaminants which could be removed. Optical fiber was developed in 1970 by Corning Glass Works, with attenuation low enough for communication purposes and at the same time GaAs semiconductor lasers were developed that were compact and therefore suitable for transmitting light through fiber optic cables for long distances. In 1973, Inc. co-founded by the inventor of the laser, Gordon Gould, received a contract from ARPA for the one of the first optical communication systems. Developed for Army Missile Command in Huntsville, the system was intended to allow a short-range missile to be flown remotely from the ground by means of a five kilometer long optical fiber that unspooled from the missile as it flew. After a period of research starting from 1975, the first commercial fiber-optic communications system was developed which operated at a wavelength around 0.8 μm and used GaAs semiconductor lasers.

This first-generation system operated at a bit rate of 45 Mbit/s with repeater spacing of up to 10 km. Soon on 22 April 1977, General Telephone and Electronics sent the first live telephone traffic through fiber optics at a 6 Mbit/s throughput in Long Beach, California. In October 1973

The Secret of the Caves

The Secret of the Caves is Volume 7 in the original The Hardy Boys Mystery Stories published by Grosset & Dunlap. This book was written for the Stratemeyer Syndicate by Leslie McFarlane in 1929. Between 1959 and 1973 the first 38 volumes of this series were systematically revised as part of a project directed by Harriet Adams, Edward Stratemeyer's daughter; the original version of this book was rewritten in 1965 by Andrew E. Svenson resulting in two different stories with the same title; the book begins with Chet Morton showing off his new metal detector to the Hardy boys and Biff Hooper while inviting them to camp at Honeycomb Caves. Meanwhile, their father, Fenton Hardy, is working to protect a Coastal Radar Station from sabotage during its construction, they are interrupted by Mary Todd who tells them that her brother, Morgan Todd, is missing and asks Fenton to find him. The Hardy boys and their father decide to team up to both find Morgan Todd and protect the Coastal Radar Station; the Hardy boys meet Todd's colleague, Cadmus Quill.

A clue leads them to Rockaway, but when it is mentioned they notice strange behavior from Cadmus Quill. While driving to Rockaway they hear a radio report that the radar station has been damaged, so they instead return to Bayport, their help is not needed so they leave for Rockaway, stopping at Palis Paris to purchase a spinning wheel for their Aunt Gertrude. When they stop in at Tuttle's General Store Mr. Tuttle warns them to keep away from Honeycomb Caves because people have seen strange lights and heard shooting coming from the caves. Instead of leaving, the boys decide to camp at Honeycomb Caves with Biff. At the caves they meet a strange hermit who invites them for breakfast chases them off and shoots at Frank, their adventure continues with Callie Shaw, Iola Morton and Mary Todd trying to get jobs at the Palis Paris, Biff getting knocked out while waiting in the parking lot, Chet's metal detector exploding and the Hardy boys' boathouse catching on fire. The story concludes with the Hardy boys finding a submarine delivering supplies to the hermit in the caves.

They explore the cave and learn that the caves have an underground passage to Palis Paris where a device was being built to interfere with the new Coastal Radar Station. The Hardy boys trap the criminals, including Cadmus Quill, in the cave while the State Police enter from the other end and arrest them all; the Navy intercepts the submarine to find Morgan Todd being held hostage. The revised edition was used for an episode of the Hardy Boys animated series and a View Master version exists

Center for Education Reform

The Center for Education Reform is an education reform organization headquartered in Washington, D. C. Founded in 1993, CER advocates for school choice; the Success and Opportunity through Quality Charter Schools Act was introduced into the United States House of Representatives on April 1, 2014 and passed in the House on May 7, 2014. The Center for Education Reform was critical of the bill, cautioning that "it is nothing more than a natural progression of the federal government becoming too involved in charter school policy; the organization argued that "the federal government is taking too much of a direct role in defining'quality' and'high performance' charter schools," taking away power from the states to make their own decisions about what charter schools qualify for grants. They argued that this takes away the autonomy and innovation that define charter schools, discounts parental choices about schools, due to the formulaic nature of these evaluations, discourages charter management organizations from taking over failing schools.

Organizational Profile – National Center for Charitable Statistics