APPARATUS FOR BROADBAND WAVELENGTH CONVERSION OF DUAL-POLARIZATION PHASE-ENCODED SIGNAL
An apparatus and method for wavelength conversion of a signal, for example, a dual-polarization signal, is disclosed. The apparatus implements a single-loop counter-propagating wavelength conversion scheme which provides both up-conversion and down-conversion of the signal within the same loop. Nonlinear wavelength conversion devices in the loop provide both up-conversion and down-conversion of the polarization components of the signal within the loop depending on whether the polarization component travels through the nonlinear conversion device in a clockwise or a counter-clockwise direction. The wavelength-converted signal is available to be extracted from the wavelength-conversion loop. An all-optical wavelength-division multiplexing transponder based on the wavelength-conversion scheme is also disclosed.
1 . A wavelength converter, comprising:
an input for receiving a signal having a first wavelength; and
a wavelength-conversion loop capable of converting the first wavelength of the signal to a second wavelength, the first wavelength and the second wavelength separated from each other by a broad spectral range;
wherein the wavelength-conversion loop is capable of up-converting the first wavelength to the second wavelength without using broadband components.
2 . The wavelength converter of claim 1 , wherein the wavelength-conversion loop is capable of down-converting the second wavelength to the first wavelength without using broadband components.
3 . The wavelength converter of claim 1 , wherein the wavelength-conversion loop comprises a first wavelength conversion medium and a second wavelength conversion medium.
4 . The wavelength converter of claim 3 , wherein the first wavelength-conversion medium is capable of converting the first wavelength to the second wavelength and converting the second wavelength to the first wavelength.
5 . The wavelength converter of claim 4 , wherein the first wavelength-conversion medium comprises a non-linear medium.
6 . The wavelength converter of claim 5 , wherein the first wavelength-conversion medium comprises periodically poled lithium niobate.
7 . The wavelength converter of claim 3 , wherein the second wavelength-conversion medium is capable of converting the first wavelength to the second wavelength and converting the second wavelength to the first wavelength.
8 . The wavelength converter of claim 7 , wherein the second wavelength-conversion medium comprises a non-linear medium.
9 . The wavelength converter of claim 8 , wherein the second wavelength-conversion medium comprises periodically poled lithium niobate.
10 . The wavelength converter of claim 1 , wherein:
the signal comprises a first polarization component and a second polarization component, wherein both the first polarization component and the second polarization component have the first wavelength;
the first wavelength-conversion medium converts the first wavelength of the first polarization component to the second wavelength; and
the second wavelength-conversion medium converts the first wavelength of the second polarization component to the second wavelength.
11 . The wavelength converter of claim 3 , wherein the first wavelength-conversion medium is capable of converting the first wavelength to the second wavelength and is capable of converting the second wavelength to a third wavelength.
12 . The wavelength converter of claim 3 , wherein the second wavelength-conversion medium is capable of converting the first wavelength to the second wavelength and is capable of converting the second wavelength to a third wavelength.
13 . The wavelength converter of claim 4 , wherein:
the first wavelength-conversion medium converts the first wavelength to the second wavelength or converts the second wavelength to the first wavelength depending on a direction in which the signal travels through the first wavelength-conversion medium.
14 . The wavelength converter of claim 7 , wherein:
the second wavelength-conversion medium converts the first wavelength to the second wavelength or converts the second wavelength to the first wavelength depending on a direction in which the signal travels through the second wavelength-conversion medium.
15 . The wavelength converter of claim 3 , wherein the wavelength-conversion loop comprises:
a first portion where the signal has the first wavelength; and
a second portion where the signal has the second wavelength;
wherein the first portion and the second portion are separated by the first wavelength-conversion medium and the second wavelength-conversion medium.
16 . The wavelength converter of claim 15 , wherein:
the first portion of the wavelength-conversion loop is between the first wavelength-conversion medium and the second wavelength-conversion medium and is coupled to an input of the wavelength-conversion loop; and
the second portion of the wavelength-conversion loop is between the first wavelength-conversion medium and the second wavelength-conversion medium and is coupled to an output of the wavelength-conversion loop.
17 . The wavelength converter of claim 1 , wherein:
the signal having the first wavelength has a first polarization component and a second polarization component;
one of the first and second polarization components travels in a clockwise direction within the wavelength-conversion loop; and
the other one of the first and second polarization components travels in a counter-clockwise direction within the wavelength-conversion loop;
wherein the first and second polarization components travel within the same optical path.
18 . The wavelength converter of claim 1 , wherein:
the signal having the second wavelength has a first polarization component and a second polarization component;
one of the first and second polarization components travels in a clockwise direction within the wavelength-conversion loop; and
the other one of the first and second polarization components travels in a counter-clockwise direction within the wavelength-conversion loop;
wherein the first and second polarization components travel within the same optical path.