| 摘要 |
PURPOSE:To make a device small-sized and inexpensive, by constituting it so that an incident light beam is polarized and separated by use of a thin plate-like double refractin plate having an optical axis which has been inclined by a prescribed angle in a plane. CONSTITUTION:Plane lenses 2, 4 are provided on both sides of a thin plate-like double refraction plate 1 having an optical axis alpha which has been inclined by 45 deg.C or so in a plane including an x-axis and a z-axis (forwarding direction of a light beam). The plane lenses 2, 4 have a one-dimensional refractive index distribution which decreases only in the x-axis direction in proportion to square of a distance from the center. When a light beam containing normal light beam and abnormal light beam components is made incident from an input side fiber 5, the light beam proceeds as shown by a full line, is led to a fiber 3, and on the other hand, the abnormal light beam proceeds as shown by a broken line and is separated. On the contrary, in case when a light beam containing a normal light beam component and an abnormal light beam component is made incident from the fiber 3, only the normal light beam shown by a full line is made incident to the fiber 5, and the abnormal light beam is separated as shown by an alternate long and short dash line. In this way, a device becomes small-sized and inexpensive. |
