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Acoustic Magneto Optical Modulator

IP.com Disclosure Number: IPCOM000081251D
Original Publication Date: 1974-Apr-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Levanoni, M: AUTHOR

Abstract

Described is a way by which high-speed acousto-optical modulation can be achieved through the use of magnetostrictive thin films and the magneto-optic effect. The device consists of a dielectric waveguide with ferromagnetic and magnetostrictive boundaries. These are used for indirect coupling between acoustic surface waves and optical guided waves.

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Acoustic Magneto Optical Modulator

Described is a way by which high-speed acousto-optical modulation can be achieved through the use of magnetostrictive thin films and the magneto-optic effect. The device consists of a dielectric waveguide with ferromagnetic and magnetostrictive boundaries. These are used for indirect coupling between acoustic surface waves and optical guided waves.

Acousto-optical modulators have been under considerable investigation for quite some time. All previous attempts utilize the elasto-optic interaction directly to achieve modulation. On the other hand, any mechanisms Which indirectly couple acoustics to optics are capable in effectively producing acousto-optical interactions, which can be used in acousto-optical modulation. Described is a scheme in which an acoustic surface wave is first coupled to the magnetization of a ferromagnetic film, Which in turn is coupled to an optical guided wave through the magneto-optic effect.

Referring to the figure, a single-mode dielectric waveguide 10 is shown fabricated on an appropriate substrate 12. An optical guided wave of definite polarization propagates in it. A thin ferromagnetic film 14 is deposited on top of the guide 10 with its easy axis, and hence magnetization, along the propagation direction. The optical guided wave traveling in the guide 10, will interact with the magnetic boundary through the magnetic longitudinal Kerr effect and its plane of polarization will rotate. With proper choice of interaction length and substrate, a 90 D...