NOTCH FILTER SYSTEM

A notch filter system, where multiple filter passes of a light signal may be effected for removing a target spectral component from the light signal, is provided. Advantageously, the notch filter system may be tunable. A cascade notch filter system is provided which includes multiple notch filters arranged in a cascade, each of the filters having spectral filtering characteristics and being disposed in the path of the light signal at an appropriate filter angle so that the target spectral component is filtered out of the light signal as the light signal passes therethrough. A multipass notch filter system is provided which includes a notch filter having spectral filtering characteristics, and an optical assembly for directing the light signal for multiple filter passes through the filter at an appropriate angle, so that the target spectral component is filtered out of the light signal as the light signal passes through the filter.