Evaluation of Optical Filters for DWDM-Direct in Next Generation Optical Access

In past few years, the number of users to the Fibre-To-The-Home (FTTH) technology increased fast because of the great potentialities of broadband access. Due to this trend Gigabit Passive Optical Network (G-PON) and Gigabit-Ethernet-PON (GE-PON) has been commercialized [1]. Besides wavelength-division-multiplexing (WDM)-PON has acquired accumulative attention as different technology for the next-generation networks. Still the developments on WDM-PON are in research stage, and the standards for WDM-PON have not been established yet [1, 2]. Therefore it is important to evaluate different wavelength filters in dense WDM (DWDM)-direct systems for broadband access to achieve greater spectral efficiency value and total information transmission capacity. Moreover it is important to evaluate minimal channel interval for currently available optical filter technologies: fibre Bragg grating (FBG) and thin film filter (TFF) with 100 GHz full width half maximum (FWHM) bandwidth in DWDM-direct systems for broadband access