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Cladded optical glass waveguide as planar polarizer
Author(s) -
Ansari Z. A.,
Karekar R. N.,
Aiyer R. C.
Publication year - 1999
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/(sici)1098-2760(19991220)23:6<337::aid-mop5>3.0.co;2-#
Subject(s) - polarizer , planar , materials science , optics , waveguide , optoelectronics , physics , computer science , birefringence , computer graphics (images)
Planar optical waveguide polarizers for TE 0 /TM 0 modes are fabricated on an asymmetric ion‐exchanged glass (Na + →K + ) waveguide. The thickness of the exchanged layer is about 2 μm, achieved after 2 h of the exchanged treatment, and is enough to excite a first‐order mode in the layer. Polarizers are fabricated by giving the cladding of various materials on the guide surface. For TE 0 polarization, metals (−ve dielectric constant) evaporated at 10 −5 torr with a thickness of about 250 nm measured using the Tolansky technique are used as a clad. Metals like Al, Ag, Cu, Pb, and Au are chosen for study. For TM 0 polarization, semiconducting oxide materials (+ve dielectric constant) like BaTiO 3 , Al 2 O 3 , SnO 2 , etc. are screen printed and used as a clad. The thicknesses of the printed films are measured by a light section microscope with an accuracy of 0.5 μm, and are about 20 μm. These samples are characterized using the prism‐film coupling method. In the case of metal clads, the TM 0 mode has a higher loss than the TE 0 mode while passing through the clad. Hence, the length where the TM 0 /TE 0 loss approaches almost zero is taken as the cutoff length. On the other hand, for semiconducting clads, a slightly higher attenuation of the TE 0 mode is observed than the TM 0 mode. Therefore, following the basic law of physics, 1/e times the fall of the intensity of TE 0 is treated as the cutoff condition. The cutoff lengths are observed experimentally as well as calculated theoretically. It is seen that both are in good agreement within an error of 5–10%. The cutoff lengths of the metals are compared with the reported values, and are analyzed on the basis of material purity and conductivity. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 23: 337–342, 1999.