Design of a coarse WDM bandpass filter using the Thelen bandpass design method

A starting design for a prototype bandpass is modeled as a periodic structure, following the teachings of Thelen. A sample prototype bandpass contains twenty-one cavities and, after computer optimization, manifests a quasi-Chebyshev transmissive response in its passband. When the prototype is converted to a thin film multilayer bandpass, its spectral bandwidth is 12.70 nm at the -0.5 dB transmittance level and 12.99 nm at the -25 dB level.