Effect of System Impairments on the Performance of QPSK Label-Based Photonic Router

Photonic routing has been attracting much interest to overcome the bottleneck of routing function in the broadband networks. This paper investigates theoretically the performance of an integrated-optic circuit for recognition of optical quadrature phase shift keying (QPSK) coded labels in photonic router. The analysis takes into account the effect of system impairments such as waveguide loss and coupling coefficient of waveguide couplers on system performance. The simulation results reveal that the presence of loss and deviation of coupling coefficient from the ideal level (0.5) affect strongly the contrast ratio at the output.