Search for the Cause of Asymmetric Results of Monitoring Errors in DWDM ections in the Last Two Layers

ltants, Charlevoix-the-Beautiful, MImonitored passes through a point of inflection and changes direction. This is normally at a point of integral quarter wave optical thickness (QWOT). If a previous termination was in error before or after the TP, the current layer would be correspondingly thicker or thinner than a QWOT when the layer is terminated at the next TP. When this technique is used, errors from previous layer terminations are largely compensated [1-4], and we have discussed the necessary conditions to take advantage of this effect. represent ten simulations with the stated random errors plus a trace of the ideal design spectrum in the background.Key Words: In previous reports on the sensitivity to layer thickness errors of DWDM and similar narrow band filter coatings, it was noted that the effect of monitoring errors that occur before the turning point appear more severe than those that occur after it. No satisfactory explanation had been found for this result. We report on the search for the explanation of that and related findings. The previous simulations did not deal with final corrections that might be made in the last two antireflection layers in the deposition of the design. We now also simulate those final layer adjustments, show how they might be done, and show the benefits that may be obtained