Stimulated Brillouin scattering has a wide range of applications in areas such as high resolution, high sensitivity stress and temperature sensing, variable optical delay lines, microwave photonics and all-optical signal processing. At present, the forward Stimulated Brillouin scattering effect is mainly achieved in photonic crystal fiber, which requires longer acoustic-optical interaction distance and larger injection power. In order to realize the forward stimulated Brillouin scattering effect on the chip, the waveguide needs to be designed to enhance the interaction between the light field and the sound field, reduce the waveguide length, and reduce the pump power.

Optoelectronic Devices and Integrated Functional Laboratory of Wuhan Optoelectronics National Laboratory, Prof. Junqiang Sun, Ph.D. student Zhang Ruiwen and others used hybrid acousto-optic waveguides to achieve forward-stimulated Brillouin scattering on the chip. Through theoretical simulation, they analyzed the acousto-optic interaction in the hybrid waveguide with different structures and optimized the waveguide design to enhance the forward Brillouin effect. The Brillouin frequency shift measured in the experiment reached 2.425 GHz with a corresponding Q of 1100. The hybrid acoustooptic waveguide consists of two materials that allow independent control of the light field and the sound field, with good tuning. This structure can be widely used in all-optical signal process.

The research result "Analysis of acousto-optic interaction based on forward stimulated Brillouin scattering in hybrid phononic-photonic waveguides," June 13, 2016, is published in OSA's Journal Optics Express (Vol.24, no.12, pp.13051- 13059, 2016) magazine. The research was funded by the National Natural Science Foundation of China (61377074).

(A) a beat signal measured before the multi-longitudinal mode laser is injected into the waveguide; (b) a beat signal measured after the multi-longitudinal mode laser is injected into the waveguide (no pump light); (c) The measured beat signal (with pump light); (d) The beat signal of the pump light and Stokes light.

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