US 2004/0001247 A1Published application

Wavelength converter and optical cross connect system

OwnerKazuhiro Nojimainventor

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Abstract

Provided is a wavelength converter utilizing gain non-linearity of a semiconductor optical amplifier for suppressing the degradation of extinction ratio when an inputted signal light undergoes wavelength conversion. In the wavelength converter, a first semiconductor laser outputs an optical signal with a first wavelength to be obtained when the inputted signal light undergoes the wavelength conversion, and a second semiconductor laser outputs an optical signal with a second wavelength which is in opposite phase relation to the optical signal from the first semiconductor laser, thereby producing a Mach-Zehnder interferometer. This Mach-Zehnder interferometer enables a high level of the optical signal with the second wavelength in the opposite phase relation to cancel a low level of the optical signal with the first wavelength after passing through a semiconductor optical amplifier, thus improving the extinction ratio.

Claims13

Dependent claims

A wavelength converter comprising:

a first semiconductor laser for outputting light with a constant intensity and with a first wavelength forming a wavelength to be obtained when a signal light is inputted to said wavelength converter and undergoes wavelength conversion in said wavelength converter;
a first semiconductor optical amplifier for intensity-modulating the output light with said first wavelength from said first semiconductor laser through the use of the inputted signal light so that the output light falls into an opposite phase condition with respect to the inputted signal light;
a second semiconductor laser for outputting a light with a constant intensity and with a second wavelength different from that of the inputted signal light and that of the output light from said first semiconductor laser;
a second semiconductor optical amplifier for intensity-modulating the output light with said second wavelength from said second semiconductor laser through the use of the inputted signal light so that the output light falls into an opposite phase condition with respect to the inputted signal light;
a first filter for extracting a light with said second wavelength from the output light from said second semiconductor optical amplifier;
a third semiconductor optical amplifier for intensity-modulating the output light with said first wavelength from said first semiconductor laser through the use of said light with said second wavelength extracted through said first filter so that the output light falls into an opposite phase condition with respect to said second-wavelength light;
multiplexing means for multiplexing the output lights from said first and third semiconductor optical amplifiers;
and
a second filter for extracting a light with said first wavelength from a multiplexed light from said multiplexing means.

6 more elements

An optical cross connect system comprising:

a wavelength-demultiplexing type optical filter for demultiplexing a multiplexed optical signal with a plurality of wavelengths into a plurality of optical signals each having the corresponding wavelength;
a plurality of wavelength converters connected to said wavelength-demultiplexing type optical filter for receiving said plurality of optical signals as inputted signal lights, each of said wavelength converters including:
a first wavelength-variable type semiconductor laser for outputting a light with a constant intensity and with a first wavelength forming a wavelength to be obtained when the corresponding inputted signal light undergoes wavelength conversion in this wavelength converter;
a first semiconductor optical amplifier for intensity-modulating the output light with said first wavelength from said first semiconductor laser through the use of the inputted signal light so that the output light falls into an opposite phase condition with respect to the inputted signal light;
a second semiconductor laser for outputting a light with a constant intensity and with a second wavelength different from that of the inputted signal light and that of the output light from said first semiconductor laser;
a second semiconductor optical amplifier for intensity-modulating the output light with said second wavelength from said second semiconductor laser through the use of the inputted signal light so that the output light falls into an opposite phase condition with respect to the inputted signal light;
a first filter for extracting a light with said second wavelength from the output light from said second semiconductor optical amplifier;
a third semiconductor optical amplifier for intensity-modulating the output light with said first wavelength from said first semiconductor laser through the use of the light with said second wavelength extracted through said first filter so that the output light falls into an opposite phase condition with respect to the second-wavelength light;
multiplexing means for multiplexing the output lights from said first and third semiconductor optical amplifiers;
and
a second filter for extracting a light with said first wavelength from a multiplexed light from said multiplexing means;
and
an optical coupler for multiplexing the extracted lights outputted from of said second filters of said plurality of wavelength converters.

10 more elements

Dependencies are inferred from the claim text.