It is necessary to find solutions for optical transmission system’s parameters improvement because of rapid overall icrease of consumer data amount that by the Cisco forecasts will grow by 32% every year and in 2016 will reach 82 560 PB per month [27]. The tendency in the world is that the 10 Gbit/s data rate per channel in wavelength division multiplexing system is being progressively switched to 40 Gbit/s and 100 Gbit/s data rate per channel [47]. Due to the rapid development of optical transmission systems wavelength filter parameter limitations must be investigated and also new solutions must be found for more flexible and scalable wavelength division multiplexing systems. Doctoral thesis is devoted to study of wavelength filters and its parameters in wavelength division multiplexing systems, as well as, development and estimation of novel filter applications in all-optical communication systems. As a result, the thesis summarizes the completed research in which the wavelength filters applications are evaluated in both current and future optical fiber communication systems.