An optical Fiber attenuates Light due to Radiation or Absorption in the fiber in an optical information communication system.

Optical filters have many applications in Wavelength division Multiplexing (WDM) systems, including but not limited to optical Spectrum analysis, Laser testing, wavelength demultiplexing, and amplified spontaneous emission filtering. Optical communication systems like networking and Telecommunications systems rely upon laser signals for information transmission. The Point-to-Point Data transfer is achieved through the creation, modulation, amplification, and Transmission of laser signals. Data carrying laser signals pass through amplifiers, switches, filters, oscillators, and other optical components that make-up the optical communication system. Optical filters such as wavelength-selective pass filters (band pass filters) are widely used in optical communications. The band pass filters allow only light beams that are in a preset wavelength band out of all the light beams having reached the Filter to pass. An optical Fiber Amplifier is employed as a System for amplifying the attenuated light. Optical filters are a means of tuning and narrowing the Bandwidth of an optical signal. Optical filters may serve many Functions in an optical network. A tunable filter is used to extract one or a subset of optical channels from the multitude of optical channels entering the filter. The subset of extracted channels can be varied in time by dynamically modifying the filter configuration.