Performance Analysis of a Synchronized-Router-Based Flat-Passband Filter Using Multiple-Input Arrayed Waveguide Grating With Phase Errors

The filtering performance of a synchronized-router-based flat-passband filter with random phase errors is analyzed. For this purpose, an analytical model of a synchronized-router-based flat-passband filter using a multiple-input arrayed waveguide grating (AWG) with phase errors is derived without the assumption of the independence of random errors so that the model can treat general types of phase errors. For average transmittance, we proposed the analytical model for the variance of transmittance for a multiple-input AWG to predict the deviation of the transmittance. By using the proposed analytical model, device performance can be estimated once the spectral information of phase errors is given. The analysis clarifies that the frequency dependence of crosstalk reflects the spatial spectral distribution of phase errors. We also compared the transmittance characteristics of the synchronized-router-based flat-passband filter with conventional Gaussian and flat-type AWGs. We found that the crosstalk in the synchronized-router type has a different behavior from those in the conventional types, i.e., the crosstalk in the synchronized-router type has a periodic behavior according to the function of the input router. The probability distribution of the transmittance of the flat-passband filter is also calculated by random simulation and compared with the result from the analytical model. The agreement between the model and the random simulation confirms that the proposed model is effective for analytically estimating the performance of a synchronized-router-based flat-passband filter with phase errors.