Abstract: A new type of magneto-optical Faraday rotation iron garnet bulk single-crystal with composition of ReYbBiIG (Re:Tb³⁺, Ho³⁺, Y³⁺, etc.)
was designed and grown by using Bi₂O₃/B₂O₃ as main flux and using Accelerated Crucible Rotation Technique for single-crystal growth. It is
believed, that through combining of two types of Bi³⁺-substituted rare-earth iron garnets with opposite signs of Faraday rotation temperature
and wavelength coefficients, the magneto-optical properties could be much improved. Series of ReYbBiIG bulk single crystals with large magneto-optical
figure of merit, low magnetic field for saturation, low near-infrared absorption, and small Faraday rotation temperature and wavelength coefficients
were obtained, such as Ho_0.85Yb_1.12Bi_1.03Fe₅O₁₂ and Tb_2.06Yb_0.46Bi_0.48Fe₅O₁₂, etc. Investigation of ReYbBiIG used as Faraday rotator material for optical isolator indicates that our new designed and grown magneto-optical Faraday rotation crystals
are good candidate for temperature stabilized and wideband optical isolators employing in WDM optical fiber communication systems.

Key words: rare-earth iron garnet, Faraday rotation, optical isolator, magneto-optical crystals