Optical transmission line
First Claim
1. An optical transmission line in which a plurality of optical amplifiers are connected in series with optical fibers at a predetermined distance to amplify wavelength multiplexed optical signals transmitted over said optical fibers in conformity with a wavelength multiplexing communication system, said optical transmission line comprising:
- M-transmission optical filters which are connected in series with said plurality of optical amplifiers and have an M-character-shaped transmission characteristic to compensate for unevenness of gain of said plurality of optical amplifiers; and
wherein dependence of an overall gain of said plurality of optical amplifiers on wavelength is optimally equalized.
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Accused Products
Abstract
Wavelength multiplexed optical signals which are input into a first optical amplifier from an optical transmission terminal device over an optical fiber are differently amplified in respective wavelengths due to unevenness of gain of the optical amplifiers and then output. By providing M-transmission optical filters having an M-type transmission characteristic to cancel gain deviation of the optical amplifiers in respective wavelengths, a flat gain characteristic can be achieved even after the optical signals are transmitted via a plurality of optical amplifiers and a plurality of M-transmission optical filters. Also, by removing ASE in a wavelength range of 1.53 μm which prevents signal amplification in a wavelength range of 1.55 μm, the wavelength multiplexed optical signals which are sufficiently amplified can be transmitted to an optical reception terminal device over the optical fiber.
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Citations
4 Claims
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1. An optical transmission line in which a plurality of optical amplifiers are connected in series with optical fibers at a predetermined distance to amplify wavelength multiplexed optical signals transmitted over said optical fibers in conformity with a wavelength multiplexing communication system, said optical transmission line comprising:
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M-transmission optical filters which are connected in series with said plurality of optical amplifiers and have an M-character-shaped transmission characteristic to compensate for unevenness of gain of said plurality of optical amplifiers; and wherein dependence of an overall gain of said plurality of optical amplifiers on wavelength is optimally equalized. - View Dependent Claims (2, 3, 4)
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Specification