ISSN:
1077-3118
Source:
AIP Digital Archive
Topics:
Physics
Notes:
A technique for large enhancement of the diffraction efficiency of a guided-wave magnetooptic (MO) Bragg cell modulator using a nonuniform bias magnetic field in bismuth-doped yttrium iron garnet-gadolinium gallium garnet waveguide is reported. Since the velocity of propagation of the magnetostatic forward volume wave (MSFVW) varies with the bias magnetic field, a bias magnetic field of proper spatial distribution will modify its wave front and, thus, create a lensing effect upon the MSFVW. This lensing effect in turn reduces the angular beam spread of the MSFVW, and results in a higher MO Bragg diffraction efficiency. The experimental data obtained for the cases with uniform and nonuniform bias magnetic fields at the carrier center frequency range of 2.0–3.5 GHz have demonstrated a diffraction efficiency enhancement by two to six times. A diffraction efficiency as high as 70% has also been accomplished. Furthermore, the measured frequency responses indicate that the nonuniform bias magnetic field has had only a mild effect on the bandwidth of the MO Bragg cell modulator. © 1997 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.120491
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