Fabrication techniques and characteristics of Al-SiO/sub 2/ laminated optical polarizers

Techniques for fabricating laminated polarizers (LAMIPOLs), which consist of alternating laminated layers of aluminum and silica, for the wavelength region lambda >1 mu m, are investigated. The oxidation of Al films is prevented by a suitable choice of deposition conditions. The surfaces of SiO/sub 2/ films are smoothed by bias sputtering. A 10 mu m thick LAMIPOL was obtained having an insertion loss of 0.15 dB and an extinction ratio of greater than 60 dB at the wavelength of 1.3 mu m. These characteristics can be estimated from the attenuated constants of the fundamental modes even when higher modes are considered.<
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