Thin Film Filters (TFF)
From the start, dielectric thin film coatings played a vital role in the development of fiber optic communication network systems. Look inside virtually any device used in fiber optic telecommunication systems and you will find dielectric thin film coatings. The most prominent examples are dielectric thin film filter wavelength division multiplexing modules.
Given its low cost and high reliability, it is not surprising that thin film filter technology has come to dominate the wavelength division multiplexing (WDM) market. Thin film filters (TFF) are made with various deposition technologies, such as ion beam (or plasma) assisted electron beam evaporation, ion beam sputtering and microwave magnetron sputtering. Coating machines based on these technologies are commercially available but, by themselves, are often ill-suited to handle the needs of today’s dynamic market, which requires fast response to different TFF specifications with superior performance and high yield.
Ligthwaves2020 has developed an integrated optical coating control system that works with commercially available state of the art coating machines to integrate filter design, characterization, tolerance simulation and coating process control into a single package. The simulation mimics the real coating process and provides valuable insights into yield and performance even before the real coating run begins. Both quarter-wave designs and non-quarter-wave designs can be optimized by the software and controlled precisely.
We have successfully developed many sophisticated TFF products based upon this process, such as 50 GHz DWDM, 100 GHz 4-skip-0 wideband WDM, highly accurate gain flattening filters, standard metallized fiber, ITO coatings and ultra wideband antireflection coatings. The integration of multi-layer dielectric thin films with sub-wavelength diffractive gratings represents the next step in dielectric TFF technology.