On influence of optical accuracy of the band-pass thin-film filter design for coexistence-type colorless WDM-PON

摘要

The future coexistence of Gigabit-capable passive optical networks (GPON) and wavelength division multiplexing PON (WDM-PON) requires the wavelength band separation of optical signals for GPON downstream (1480 - 1500 nm) and WDM-PON (1500 - 1620 nm). A new multi-layer thin-film structure of the band separation filter is proposed and numerically investigated to separate these spectral bands at the wavelength of 1500 nm with the spectral transmittance edge as steep as possible and at least of 32 dB insertion loss at 1500 nm. This article is focused on modeling transmission characteristics of the design of a GPON and WDM-PON band separation thin-film filter with the aim of detecting the impact of optical properties of materials involved, namely the number of the designed layers and material dispersion. Additionally, we report on the investigation of the influence of layer thickness deviations on the transmission characteristics of the band-pass filter aimed for separating GPON and WDM-PON wavelength regions.