REDUCTION CONDITION SELECTION METHOD FOR POLARIZING ELEMENT, METHOD FOR PRODUCING POLARIZING ELEMENT, POLARIZING ELEMENT PRODUCED BY THE METHOD, AND OPTICAL ISOLATOR USING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a polarizing element composed of a metal particulate-dispersed type polarizing glass in which isolation of ≥30 dB can be attained even in a pigtail type optical isolator.;SOLUTION: A method for obtaining the condition of reduction is disclosed by which a polarizing element produced by reducing a glass substrate in which the acicular particles of silver halide or of first copper are dispersed so as to be oriented to one direction in a reducing atmosphere, thus forming a reduction layer comprising acicular metal silver or copper exhibits an extinction ratio suitable to be used in a pigtail type optical isolator. For each of samples of the polarizing elements obtained by reducing the test samples of a glass substrate under at least two reduction conditions, the distance to a light receiver is set within 100 mm, an extinction ratio is measured with light having a wavelength of 1.3 to 1.6 μm, the polarizing element sample in which the extinction ratio is the maximum or the highest is selected, and a reduction condition under which the selected polarizing element is prepared is determined as reduction condition under which an extinction ratio suitable for a pigtail type light isolator is exhibited. Also a method for producing a polarizing element under the reduction condition obtained by the above method, the polarizing element and an optical isolator are disclosed.;COPYRIGHT: (C)2009,JPO&INPIT