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New Tracking and Cutting Modes for Complex DWDM-Type Filters

May 8, 2020

DWDM Filter Model

Intellemetrics has integrated two new features into it’s FilmMaker and FilmDirector software suites for monitoring and controlling the growth of complex quarter wave stacks for the production of DWDM-type filters.

The first features is a new single tracking mode that enables cutting at the turning points with an unparalleled level of precision. Cut errors on these layers are essentially reduced to zero, even with significant amounts of signal smoothing that would otherwise cause a phase delay between the raw signal and the smoothed signal. This results in the ability to manufacture highly complex film stacks such as DWDM filters with 200 layers and 9 cavities with high yields.

The second feature is also aimed at the DWDM-type coating application space, and consists of a new Smart Time Cut algorithm for layers that need to be cut based on time alone. This can be the case in certain film stacks deposited in coating systems that do not contain a crystal monitoring system. In these cases, certain layers may need to be cut based purely on time. The issue has always been that deposition rates may vary slightly from run-to-run. This algorithm keeps track of previous layers of the same material and applies the most recent estimate of deposition rate to the time cut layers, thereby accounting for run-to-run deposition rate variations.