Dispersion Compensation Requirements for Optical CDMA Using WDM Lasers
Optical code division multiple access (O-CDMA) uses very narrow transmission pulses and is thus susceptible to fiber optic link impairments. When the O-CDMA is implemented as wavelength/time (W/T) matrices which use wavelength division multiplexing (WDM) sources such as multi-frequency laser transmitters, the susceptibility may be higher due to: (a) the large bandwidth utilized and (b) the requirement that the various wavelength components of the codes be synchronized at the point of modulation and encoding as well as after (optical) correlation. A computer simulation based on the nonlinear Schroedinger equation, developed to study optical networking on the National Transparent Optical Network (NTON), was modified to characterize the impairments on the propagation and decoding of W/T matrix codes over a link of the NTON. Three critical link impairments were identified by the simulation: group velocity dispersion (GVD); the flatness of the optical amplifier gain; and the slope of the GVD. Subsequently, experiments were carried out on the NTON link to verify and refine the simulations as well as to suggest improvements in the W/T matrix signal processing design. The NTON link measurements quantified the O-CDMA dispersion compensation requirements. Dispersion compensation management is essential to assure the performance of W/T matrix codes.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15005687
- Report Number(s):
- UCRL-JC-146464; TRN: US0305602
- Resource Relation:
- Journal Volume: 4653; Conference: Photonics West, San Jose, CA (US), 01/19/2002--01/25/2002; Other Information: PBD: 10 Dec 2001
- Country of Publication:
- United States
- Language:
- English
Similar Records
High spectral efficiency optical CDMA system based on guard-time and optical hard-limiting (OHL)
Development of Pulse Position Modulation/Optical CDMA (PPM/O-CDMA) for Gb/s Fiber Optic Networking