Dispersion produced by turning a multilayer thin film Gires-Tonrnois (G-T) Interferometer is accurately calculated with the aid of computer. Experimental Investigation has been carried out. This device can provide adjustable dispersion by turning the angle of G-T interferometer. A G-T interferometer with suitable construction parameters ean be used as a cavity mirror to compensate upchirp in the cavity in order to get shorter optical pnlses.