An all-optical multibit correlator using the multistage cascaded quantum dots semiconductor optical amplifiers Mach-Zehnder interferometer (QD-SOA MZI) is presented with the example of an 8-bits correlator. The simulations demonstrate the correlator pulse with ultrahigh quality at the bit rate of 500 Gbps. For the ultrahigh bit-rate applications, the ultrafast dynamics of the QD-SOA are investigated with the pulse/spectra distortion, gain dynamics, phase dynamics, and the frequency chirp of the optical pulse. All-optical logical gates XOR and AND based on the QD-SOA MZI are simulated with the consideration of many nonlinear dynamics, such as the carrier injection, carrier depletion, carrier density fluctuation, carrier heating, and the spectra hole-burning in the rate equations scheme.
A prototype of the temperature sensor based on the nano-wire Silicon-on-Insulator (SOI) waveguides, with air cladding
or SiO<sub>2</sub> cladding, is proposed with the principle of two mode interference (TMI) in the two mode nano-wire SOI
waveguides. The beatlength, between the two modes with same polarization in the two-mode regime, are shown with the
dependence on the waveguide parameters. The effects of the birefringence on the temperature sensor are discussed.