X-band magneto-optic Bragg cells using bismuth-doped yttrium iron garnet waveguides

Abstract

Guided-wave magneto-optic Bragg cells at X-band microwave frequencies using magnetostatic forward volume waves (MSFVWs) in bismuth-doped yttrium iron garnet-gadolinium gallium garnet (Bi-doped YIG-GGG) waveguides are reported for the first time. Performance figures that have been obtained at an optical wavelength of 1.303 μm include a center frequency tuning range of 3.7–12.0 GHz, a diffraction efficiency of 12% at the magnetostatic wave power of 56 mW, a linear dynamic range >40 dB, and a −3 dB magneto-optic bandwidth of 150 MHz. These results represent a significant improvement over those obtained previously with the Bragg cells using pure YIG-GGG waveguides. Maximum scan angle of 6° and 5.3° were also measured, respectively, by tuning the rf frequency ∼10.0 GHz at a fixed dc magnetic field of 3660 Oe and by varying the dc magnetic field ∼3660 Oe at a fixed rf frequency of 10.0 GHz. A frequency resolution of 30 MHz was measured with rf spectral analysis experiments carried out at 12 GHz. Finally, a Faraday rotation coefficient as large as −2313°/cm was measured for the Bi-doped YIG-GGG waveguides.