Optical isolator for use in wavelength band of 780 to 820 nm

Abstract

An optical isolator for use in a wavelength band of 780 to 820 nm including a Faraday rotator made of a composite oxide containing oxide represented by following formula (A) as main component and having Verdet constant at wavelength of 800 nm of 0.80 min/(Oe·cm) or more, and hollow magnet arranged around outer periphery of Faraday rotator, wherein sample length L (cm) of Faraday rotator is in range represented by following inequality (1), and magnetic flux density B (Oe) applied to Faraday rotator is in range represented by following inequality (2) ( Tb x ⁢ R 1 - x ) 2 ⁢ O 3 ( A ) wherein “x” satisfies 0.8≤x≤1.0, and R includes at least one element selected from group consisting of scandium, yttrium, and lanthanoid elements other than Tb (terbium) 0.8 ≤ L ≤ 1.1 ( 1 ) B ≤ 0. 4 × 1 ⁢ 0 4 . ( 2 )

Dependencies are inferred from the claim text.