Evanescent Wave Fiber Optic Couplers: Three Methods

Three methods have been used successfully in fabricating evanescent optical couplers with single mode and multimode optical fibers. These approaches comprise cementing fibers into plates before grinding and polishing, embedding the fibers in lower melting temperature glass before grinding and polishing, and stretching adjacent fibers while heating them. Comparisons are made among the couplers produced by the three methods with regard to stability of the coupling ratio with ageing, changes in temperature and changes in light polarization.