US Patent 7253873 Dynamic gain equalizer

A dynamic gain equalizer (1) comprises a spectroscope (4) for separating a light entering from an incoming end, a liquid crystal optical switch (5) for receiving spectral components separated by the spectroscope (4), and a lens system (3) arranged between the incoming end and the spectroscope (4) and/or between the spectroscope (4) and the liquid crystal optical switch (5). The liquid crystal optical switch (5) changes the light intensities of incoming spectral components for each wavelength and sends them out. The dynamic gain equalizer selectively controls the spectral components of specific wavelengths and equalizes the light intensities for the wavelengths without using a mechanical moving part such as a MEMS.