On wavelength blocking for XG-PON coexistence with GPON and WDM-PON networks

Reference optical configuration for coexistence of 10-Gigabit-capable passive optical networks (XG-PON) with Gigabit passive optical networks (GPON) according to ITU-T G.987.1 standard recommends the usage of specific wavelength blocking filters (WBF). In this contribution, WBFs are designed to separate wavelength bands allocated for XG-PON downstream and upstream signals. The WBFs are proposed to guarantee high filter contrast factors achieved by steep transmission curves in the vicinity of cut-on/cut-off wavelengths of the specific allocated wavelength bands and facilitate migration from legacy GPON to XG-PON. Their deployment protects the allocated wavelength bands from the undesirable interference of GPON with XG-PONs. Wavelength blocking for future wavelength-division-multiplexed PONs is discussed too.