A mixed rare-earth iron garnet single crystal of ReYbBiIG for high-performance magneto-optical devices

A new type of magneto-optical (MO) Faraday rotation (FR) iron garnet bulk single-crystal with composition of ReYbBiIG (Re: Tb 3+ , Ho 3+ , etc.) was designed and grown by using Bi 2 O 3 /B 2 O 3 as the main flux and the accelerated crucible rotation technique. Through the combining of two types of Bi 3+ -substituted rare-earth iron garnets with opposite signs of FR, temperature and wavelength coefficients, the MO properties can be much improved. A series of nearinfrared (NIR) optical materials of ReYbBiIG with large MO figure of merit (>18°/dB), low saturation magnetic field (∼ 1.2 x 10 6 A/m), low NIR optical absorption (<6.58 cm -1 ), and very small FR temperature and wavelength coefficients at λ = 1.55 μm were obtained, including Ho 0.85 Yb 1.12 Bi 1.03 Fe 5 O1 2 and Tb 2.06 Yb 0.46 Bi 0.48 Fe 5 O 12 , etc. Indications are that these newly designed and grown MO FR crystals are good candidates for temperature stabilized and wideband optical isolators employed in wavelength division multiplexing optical fiber communication systems.