An optical spectral compensation scheme is proposed to flatten the chips spectra over an arrayed-waveguide grating (AWG), router-based code-division multiplexing (CDM) network. Spectral coding chips are attained by slicing the spectrum from a broadband light source (BLS) and then coded with an AWG router to form a stream of spectral chips. The chips spectra sliced from the contemporary BLS are usually not flat and will induce coding chips with unequal power levels. The resulting unequal chips power will cause multiple-access interference (MAI) at the receiver. Chips spectra compensation is therefore examined with backward-pumped fiber Raman amplifiers (FRAs). The study adopts a genetic algorithm (GA) and linear matrix to flatten the power spectra of coded wavelength-division multiplexing (coded-WDM) chips by identifying the optimal pump wavelengths and pump power of backward-pumped FRAs. The signal-to-interference ratio (SIR) is evaluated with spectral compensation, and the performance improvement is found to be in the range of ∼20 dB.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics