Apparatus and method for reducing distortion of an optical signal
AssigneeLeonardo Mw Ltd
InventorsIan Flint, Mohammed Alom, Shyqyri Haxha
Life of this patent
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Abstract
An RF signal to be carried by an optical link is modulated onto two optical beams. The modulators are tuned differently so that the distortion products carried on one beam are relatively larger compared to the fundamental compared with other beam. One of the beams is optically upconverted by the appropriate Brillouin shift frequency and the two beams counter-propagated through an optical waveguide in order to create a Brillouin grating. The grating acts to separate the distortion products from the fundamental so as to provide at an output of the link a signal in which the distortion products are insignificant is not absent.
Claims26
Apparatus for reducing distortion in an optical signal, the apparatus comprising:
- an optical waveguide;
- an input for receiving a signal;
- means for generating a first coherent light beam modulated to carry the signal received at the input,
- a means for generating a second coherent light beam modulated to carry the signal received at the input;
- wherein the optical frequencies of the first coherent light beam and second coherent light beam are selected to differ to satisfy a Brillouin condition;
- and wherein the first and second coherent light beams are selected to have different fundamental to distortion product ratios;
- the apparatus being arranged to cause the first coherent light beam to propagate along the optical waveguide in a first direction, and the second coherent light beam to propagate along the optical waveguide in an opposite direction to generate a dynamic Brillouin grating in the optical waveguide through stimulated Brillouin scattering.
A radio receiver system including:
- a radio frequency receiver and an optical link, the optical link comprising:
- an optical waveguide;
- an input for receiving a signal from the radio frequency receiver;
- means for generating a first coherent light beam modulated to carry a signal received at the input;
- a means for generating a second coherent light beam modulated to carry the signal received at the input;
- wherein the optical frequencies of the first coherent light beam and second coherent light beam are selected to differ to satisfy the Brillouin condition;
- and wherein the first and second coherent light beams are selected to have different fundamental to distortion product ratios;
- the apparatus being arranged such that the first coherent light beam propagates along the optical waveguide in a first direction and the second coherent light beam propagates along the optical waveguide in an opposite direction to generate a dynamic Brillouin grating in the optical waveguide through stimulated Brillouin scattering.
A method for reducing distortion in an optical signal, the method comprising:
- modulating a first coherent light beam to carry a signal and propagating the modulated coherent light beam along an optical waveguide;
- modulating a second coherent light beam to carry the signal and propagating the modulated coherent light beam along an optical waveguide;
- and
- generating a dynamic Brillouin grating in the optical waveguide using stimulated Brillouin scattering by propagating the second coherent light beam through the optical waveguide in an opposite direction to the first coherent light beam;
- wherein the first and second coherent light beams are modulated so as to have different fundamental to distortion product ratios.
A method for reducing distortion in an optical signal of a photonic link connected to a RF receiver or RF transmitter, the method comprising:
- modulating a first coherent light beam to carry a signal received by the RF receiver or transmitted by the RF transmitter, and propagating the modulated first coherent light beam along an optical waveguide;
- modulating a second coherent light beam to carry the signal received by the RF receiver or transmitted by the RF transmitter and propagating the modulated second coherent light beam along an optical waveguide;
- and
- generating a dynamic Brillouin grating in the optical waveguide using stimulated Brillouin scattering by propagating the second coherent light beam through the optical waveguide in an opposite direction to the first coherent light beam;
- wherein an optical frequency of the first coherent light beam and second coherent light beam are selected to differ by an amount to satisfy a Brillouin condition;
- and wherein the first and second coherent light beams are modulated so as to have different fundamental to distortion product ratios.
Dependencies are inferred from the claim text.