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Four Wave Parametric Amplification of Fiber Optic Communication Signals

IP.com Disclosure Number: IPCOM000037435D
Original Publication Date: 1989-Jan-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Levenson, MD: AUTHOR [+2]

Abstract

An all-optical method is described for transmitting fiber optic communication signals over long distances and compensating for loss at optical data rates. Pump waves are injected into the fiber at various locations along the fiber.

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Four Wave Parametric Amplification of Fiber Optic Communication Signals

An all-optical method is described for transmitting fiber optic communication signals over long distances and compensating for loss at optical data rates. Pump waves are injected into the fiber at various locations along the fiber.

The range over which signals can be transmitted in an optical fiber is set by attenuation. Electronic and previously known optical methods of amplification and regeneration limit the bandwidth. Four wave parametric amplification of the signals can overcome these limitations. In this invention, the amplification medium is the fused silica optical fiber itself.

Four wave parametric amplification is a nonlinear process where a pump wave simultaneously amplifies two frequency bands (signal and idler) symmetrically shifted from the pump. In glass optical fibers, the gain is typically g=30P (1/km) where P is the pump power in Watts. Fibers with zero or anomalous group velocity dispersion are capable of amplification over very large bandwidths.

Assume the data was single side-band suppressed carrier modulation centered at frequency ws. To amplify that signal band, a pump wave is injected at frequency wp using a resonant directional coupler. The signal wave is amplified, and a corresponding idler wave is generated at frequency 2wp-ws. The amplification counteracts the loss over part of the fiber, but eventually, a subsequent amplification step may be required.

The presence...