CPC G02F 1/093 (2013.01) [C04B 35/50 (2013.01); G02F 1/0136 (2013.01); G02F 1/055 (2013.01)] | 7 Claims |
1. An optical isolator comprising:
a Faraday rotator comprising a trivalent ion exchange TAG (terbium-aluminum garnet), and
arranged around the Faraday rotator, (i) a central hollow magnet and (ii) a first hollow magnet unit and a second hollow magnet unit each arranged to sandwich the central hollow magnet in an optical axis direction,
wherein:
a magnetic flux density B [T] in the Faraday rotator and an optical path length L [mm] where the Faraday rotator is arranged satisfy:
0<B (1) and
14.0≤L≤24.0 (2),
the central hollow magnet and the first and second hollow magnets are neodymium-iron-boron (NdFeB) type magnets, and
the Faraday rotator has, at an optical path length of L≤24.0 mm, optical characteristics comprising:
an absorption coefficient of 0.001 cm−1 or less,
an extinction ratio of 25 dB or more, and
a lower insertion loss of 0.04 dB or less.
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