Patent ID: 6236483
Filing Date: 2001-05-22
Classification: H04J,H04K

Abstract:
In an optical code-division multiple access communication system in which a plurality of users are connected to an optical fiber, at least one user transmitting optical signals over the fiber and at least one user receiving optical signals from the fiber, an encoding apparatus at the transmitting user for generating a modulated and encoded beam of light carrying a data signal, the encoding apparatus comprising:a broad band light source for providing a beam of light;an optical modulator for modulating the intensity of the beam of light according to the data signal;a first optical chamber having a first code, the first code having a sequence of digits each having one of at least two values, the first optical chamber defining a plurality of spectral components in the beam of light each corresponding to a digit of the first code, the first optical chamber attenuating the intensity of each spectral component of the beam of light according to the value of the corresponding digit of the first code to generate an encoded beam of light, wherein a spectral component is substantially completely removed when the corresponding code digit has a first value;wherein the first code comprises a first and a second section of identical lengths, wherein the first section defines a first sub-code and wherein each digit in the second section has the first value; andwherein the first sub-code is selected from a set of unipolar codes in which each code in the set is orthogonal to the difference between any other code in the set and the complement of the other code; andan optical coupler for injecting the modulated and encoded beam of light into the optical fiber.