| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a low-cost optical fiber which is free of deterioration in transmission wavelength characteristics and does not return reflected light to an incident side and an optical filter module relating to an optical filter used for optical communication, optical measurement, etc., and an optical fiber module. <P>SOLUTION: The optical filter 1 is equipped with an optical filter element 4 which multiplexes and demultiplexes light, a first birefringent plate 2 which is arranged on the light incident surface side of the optical filter element 4, is no in the refractive index to ordinary light, is ne in the refractive index to extraordinary light and is (d) in board thickness, and a second birefringent plate 3 which has an optical axis orthogonal with the optical axis of the first birefringent plate 2, is arranged on the light incident surface side of the optical filter element 4 adjacently to the first birefringent plate 2 and has the same refractive indices no and ne, and board thickness (d) as those of the first birefringent plate 2. The first and second birefringent plates 2 and 3 are so constituted as to satisfy the relation 2(no-ne)d=(M+1/2)λwhen the wavelength of the light is defined asλand an arbitrary integer as M. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
