Large-Size Crystal Growth and a Fiber-Coupled Acousto-Optic Device of TiTe3O8

TiTe3O8 has been recognized as an excellent acousto-optic crystal with isotropic optical properties. In this work, the TiTe3O8 crystal with sizes reaching up to 55 × 32 × 40 mm3 was grown by the top-seeded solution growth method. The full width at half maximum of a high-resolution X-ray diffraction is 38 arcsec. A fiber-coupled acousto-optic device with polarization ability is successfully designed and fabricated based on the TiTe3O8 crystal. The rise time, insertion loss, and on–off extinction are determined to be 36 ns, 1.8 dB, and 58 dB, respectively, which are better than those of TeO2 devices. The polarization extinction ratio is about 19 dB. An actively Q-switched ytterbium-doped all-fiber laser operating at 1060 nm was successfully realized. The results show that the TiTe3O8 acousto-optic modulator is a potential Q-switch for all-fiber lasers.