Patent ID: 6600601
Filing Date: 2003-07-29
Classification: G02F,Y10S

Abstract:
A multi-stage polarization-independent optical isolator comprising:an even number of optical isolators assembled to each other, each of said optical isolators including a first birefringent wedge plate having an inclined plane directed to a light incoming side, having a first wedge equal thickness line; a second birefringent wedge plate having an inclined plane directed to a light outgoing side, having a second wedge equal thickness line, wherein said first wedge equal thickness line and said second wedge equal thickness line are parallel with respect to each other; and a Faraday rotator element disposed between said first and second birefringent wedge plates; wherein a non-inclined plane of said first birefringent wedge plate is adhesively bonded to a light incoming plane of said Faraday rotator element, and a light outgoing plane of said Faraday rotator element is adhesively bonded to a non-inclined plane of said second birefringent wedge plate; and said first and second birefringent wedge plates and said Faraday rotator element thus adhesively bonded to each other are disposed in a cylindrical magnet and where said first wedge equal thickness line defines the direction of a wedge equal thickness line of the birefringent wedge plates of one of said plurality of optical isolators of which said first birefringent wedge plate is a member; wherein the crystal axes, of birefringent wedge plates directly opposed to each other, are offset 90Â° with respect to the common center axis thereof in the light traveling direction; said wedge equal thickness line of the birefringent wedge plates of one of said plurality of optical isolators is offset a specific angle from the wedge equal thickness line of said birefringent wedge plates of another of said plurality of optical isolators; and said optical isolators are adhesively bonded to each other in a state in which a stepped portion provided at an end of said cylindrical magnet of one of said plurality of optical isolators is fitted to a stepped portion provided at an end of said cylindrical magnet of another of said plurality of optical isolators.