A novel OCDMA drop unit based on fiber gratings and 2D wavelength-time codes

A novel drop unit for the optical code-division multiple access（OCDMA） based on fiber Bragg gratings and two-dimensional wavelength-time code is studied. The simple OCDMA drop unit can drop a code channel without disturbing the rest code channels. A similar unit for dropping a group of code chennels is also proposed. Numerical simulation is given. The system delay can decrease by substituting the electrieal driving optical switch with a specific optical driving. The single channel drop unit can also be the basis for multiple channels drop.