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Optical Fiber

The greatest invention of the 20th century originated in Sendai The birthplace of optical communications - Sendai

Optical communications that support the present information network

This technology, which greatly influenced the communications environment towards the upcoming advanced information society, was created at the Tohoku University Electric Communication Institute in 1964, when the Tokyo Olympics were held. The developer was Professor Junnichi Nishizawa.

Optical communications that convert information or data into optical signals consist of three factors, namely, sending, transmitting, and receiving, each one indispensable for optical communications.

Though it may sound far stretched, Professor Nishizawa invented or developed all of these technologies and opened the way for commercialization, which earned him the title of the "father of optical communications." These contributions in optical communication technology by research and invention are the reasons why he was nominated several times for the Nobel Prize.

Optical lasers have the characteristic of traveling straight for long distances while maintaining its shape. Professor Nishizawa developed a small but strong semi-conductor laser as an element that oscillates the laser. He also developed an optical fiber consisting of a core and a clad that use the differences in the refractive index by combining different glass materials and he also demonstrated that glass can conduct light.

As soon as a light source (semiconductor laser) and a channel for the light (optical fiber) became available, this marked the first step for practical application of optical communications.

It is nearly impossible to estimate how many people will reap the benefits from the widespread use of optical communication. Innovative technology that is forever changing the world is still continuing to be produced in Sendai.


The monument of "The birthplace of optical communications" in Tohoku University

Optical communications technologies invented or developed by Professor Junnichi Nishizawa:
Sending = an element that oscillates high precision laser light using a semiconductor - "semi-conductor laser" (1957)
Transmitting = A channel for transmitting over long distances while completely reflecting the oscillated light without any losses - "optical fiber" (1964)
Receiving = Optical receiving element that precisely receives and detects incoming light and converts it into electrical signals - "avalanche photodiode" (1952),
"pin photodiode" (1953)


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