A novel approach for an optical direct-sequence spread spectrum is presented. It is based on the complementary processes of broad-band parametric down-conversion and up-conversion. With parametric down-conversion, a narrow-band continuous-wave (CW) optical field is transformed into two CW broad-band white-noise fields that are complex conjugates of each other. These noise fields are exploited as the key and conjugate key in optical direct-sequence spread spectrum. The inverse process of parametric up-conversion is then used for multiplying the key by the conjugate key at the receiver in order to extract the transmitted data. A complete scheme for optical code-division multiple access (OCDMA) based on this approach is presented. The salient feature of the approach presented in this paper is that an ideal white-noise key is automatically generated,leading to high-capacity versatile code-division multiple-access configurations.
© 2004 IEEE
Avi Pe'er, Barak Dayan, Yaron Silberberg, and Asher A. Friesem, "Optical Code-Division Multiple Access Using Broad-Band Parametrically Generated Light," J. Lightwave Technol. 22, 1463- (2004)