Digital Signal Processing Reference
In-Depth Information
By using the coupled amplitude equations to study interaction of optical pulses
in the SOI waveguides and showed the optical wavelength conversion. The non
linear phenomenon of FWM is used to generate wavelength conversion. It is
considered first that the impact of free carriers and showed that, index changes
induced by them have a significant impact on FWM.
The influence of pump power, dispersion, wavelength, and nonlinear absorp-
tion on the conversion efficiency is discussed in presence of noise figure. In order
to achieve high conversion efficiency, the pump wavelength should be operated in
anomalous GVD regimes. Conversion efficiency in silicon waveguides decreases
with the increasing pump power and the noise figure is degraded due to the TPA
and TPA-induced FCA at the high pump power. With the increase in free carrier
lifetime, conversion efficiency will decrease and the noise figure will increase
accordingly. In practical application, the high conversion efficiency and low noise
figure can be achieved by choosing suitable parameters. It is evident that the non-
linear loss phenomenon of TPA and FCA are dominant at low pump powers, with
increased pump power the FWM becomes phase matched at the wavelength under
consideration. For the wavelengths 20-30 nm far from the pump, the gain over-
comes nonlinear losses resulting in higher CE. Noise figure is strongly associated
with carrier recombination life time and the life time should be of the order of
300 ps or less. Given simulation shows the Bit rate around 10 GHZ, pulse width
1 ps, signal wavelength 1,530 nm for a SOI waveguide length of 1 cm are better
choice for optimum conversion efficiency.
The simulation shows the Bit rate around 10 GHZ, pulse width 1 ps, signal
wavelength 1,530 nm for a SOI waveguide length of 1 cm are better choice for
optimum conversion efficiency. The further improvement can be achieved if TPA-
induced FCA loss is reduced and NF improved in silicon waveguides.