Original light source or light source adopting a method to modulate light intensity with a stack of gain-flattening filters

A method for an original light source or a light source to modulate waveform intensity with a stack of gain-flattening filters including following procedures:

• preparing said stack of gain-flattening filters made of more than two or three aligned single filters, each of said filter made by stacking on a substrate with several layers of optical thin films having different refractive indexes or stacking on both sides of a substrate with several different stacked films made of said optical thin films having different refractive indexes;
• followed by modulating said waveform intensity with said stack of gain-flattening filters installed at an emitting end of said original light source or said light source, wherein an angle of each single filter can be adjusted to change spectrum of a whole set of filters so that said waveform intensity of said original light source or said light source is changeable or flattened when said emitted original light source or said light source is modulated with said stack of gain-flattening filters.