Optical isolator for a wavelength band of 600-800 nm

Patent metadata

Field	Value
Publication number	US-9429778-B2
Application number	US-201414310130-A
Country	US
Kind code	B2
Filing date	Jun 20, 2014
Priority date	Jul 12, 2013
Publication date	Aug 30, 2016
Grant date	Aug 30, 2016

Abstract

An optical isolator for use with a wavelength band of 600-800 nm is improved in that it has a Faraday rotator made of an oxide material in which said oxide material contains (Tb x R 1-x ) 2 O 3 such that 0.5≦x≦1.0, and R is scandium, yttrium or any lanthanoid but Tb.

First claim

Scopes of what is claimed:

1. A optical isolator for use with a wavelength band of 600-800 nm, comprising:
a Faraday rotator made of an oxide material containing an oxide represented by formula (I) in an amount of 99% or higher and having a Verdet constant of 0.90 min/Oe·cm or greater at a wavelength band of 633 nm, and
a hollow magnet arranged to surround the Faraday rotator,
wherein a sample length L (cm) through which the Faraday rotator is arranged is in a range represented by an inequality (1) and that magnetic flux density B (Oe) impressed on the Faraday rotator is in a range represented by inequality (2),
wherein the formula (I), the inequality (1), and the inequality (2) are
(Tb x R 1-x ) 2 O 3   (I)

wherein 0.5≦x≦1.0, and R is at least one element selected from scandium, yttrium and any lanthanoid but Tb,
0.6≦ L≦ 1.1  (1), and

B≦ 0.5×10 4   (2).

2. An optical isolator as claimed in claim 1 , wherein said oxide is in a form of single crystal or ceramic.

3. An optical isolator as claimed in claim 1 , wherein said Faraday rotator has an insertion loss of 1 dB or lower and an extinction ratio of 30 dB or higher when said sample length L satisfies inequality (1).

4. An optical isolator as claimed in claim 1 , wherein said hollow magnet is made of a neodymium iron boron-base magnet.

5. An optical isolator as claimed in claim 2 , wherein said Faraday rotator has an insertion loss of 1 dB or lower and an extinction ratio of 30 dB or higher when said sample length L satisfies inequality (1).

6. An optical isolator as claimed in claim 2 , wherein said hollow magnet is made of a neodymium iron boron-base magnet.

Assignees

• Shinetsu Chemical Co

Inventors

• Yahagi Akira
• Watanabe Toshiaki
• Makikawa Shinji

Classifications

• G02F1/0036

  Magneto-optical materials · CPC title

• C04B35/505

  based on yttrium oxide · CPC title

• G02F1/093 Primary

  used as non-reciprocal devices, e.g. optical isolators, circulators (G02F1/0955 takes precedence) · CPC title

• C04B2235/3224

  Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide · CPC title

• C04B35/50

  based on rare-earth compounds {(non-oxide rare earth compounds C04B35/5156)} · CPC title