OPTICAL WAVEGUIDE DEVICES USING SINGLE-CRYSTAL GARNET FILMS

• US 3,764,195 A
• Filed: 02/02/1972
• Issued: 10/09/1973
• Est. Priority Date: 02/02/1972
• Status: Expired due to Term

• Current Assignee: Hyman Joseph Levinstein, Lawrence John Jr. Varnerin, Ping King Tien, Raymond Wolfe, Roy Conway Lecraw, Stuart Harry Wemple, Stuart Lawrence Blank
• Original Assignee: Hyman Joseph Levinstein, Lawrence John Jr. Varnerin, Ping King Tien, Raymond Wolfe, Roy Conway Lecraw, Stuart Harry Wemple, Stuart Lawrence Blank
• Inventors: Varnerin, Lawrence John Jr., Wolfe, Raymond, Blank, Stuart Lawrence, LeCraw, Roy Conway, Levinstein, Hyman Joseph, Tien, Ping King, Wemple, Stuart Harry
• Primary Examiner(s): Wibert, Ronald L.
• Assistant Examiner(s): Godwin, Paul K.
• Application Number:
  US05/222,779
• Time in Patent Office: 615 Days
• Field of Search: 350/96WG,150,151,160
• US Class Current: 385/130
• CPC Class Codes: G02B 6/12004 Combinations of two or more optical elements
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence
• CPC Class Codes: G02F 1/095 in an optical waveguide structure
• CPC Class Codes: H01F 10/245 Modifications for enhancing interaction with electromagnetic wave energy
• CPC Class Codes: H01S 3/0632 Thin film lasers in which light propagates in the plane of the thin film

Abstract

Thin-film optical waveguides are disclosed comprising singlecrystal rare-earth garnet films deposited on garnet substrates. Epitaxial film growth techniques, developed largely for magnetic bubble domain devices, provide films with superior optical properties either at visible or near-visible wavelengths. The thin-film optical waveguides are comprised of transparent garnet films of the general formula R3B5O12; where R can be yttrium, lanthanum, bismuth, or a rare-earth ion with an atomic number of 60 to 71 inclusive, and B an be either magnetic, i.e., iron, or nommagnetic, i.e., gallium or aluminum. The use of the former types of films can give rise to various thin-film magnetic devices suitable for integrated optical circuit arrangements. One such device which is disclosed, a thin-film magneto-optical switch and modulator, includes a light-guiding film of an iron garnet composition and a serpentine micro-circuit which is deposited on the film to carry a switching current. The device provides a continuous switching of the polarization modes of the light waves guided in the film. Similarly, by applying a microwave current to the same circuit, the guided light can be modulated.

Claims

2. A device according to claim 1 in combination with means for polarizing the beam launched into said second body and means for analyzing the beam extracted from said second body.

3. A device according to claim 2 in which the garnet crystalline material of said second body is an iron-containing ferrimagnetic garnet composition.

4. A device according to claim 3 in combination with means for applying a spatially alternating magnetic field to said second body of a selected period to produce a spatially periodic variation in the magnetization of said second body in the direction of the propagation of the beam.

5. A device according to claim 4 in which said magnetic field applying means is a serpentine microcircuit formed on one of said major surfaces of said second body for carrying an inductive electrical current sufficient to produce said spatially alternating magnetic field.

6. A device according to claim 5 in which the electrical current is a dc current for continuously switching the polarization modes of the guided beam propagating in said second body.

7. A device according to claim 5 in which the electrical current is a variable-frequency microwave current for modulating the guided beam in accordance with the applied microwave frequency.

8. A device according to claim 7 in which the easy axis of magnetization of said ferrimagnetic garnet material is in a direction parallel to said major surfaces of said second body.

9. A device according to claim 8 in combination with magnetizing means for tilting the magnetization of the ferrimagnetic garnet material into the hard direction normal to said major surfaces of said second body and in which said serpentine microcircuit tends to tilt the magnetization into the easy direction parallel to said major surfaces.

10. A device according to claim 4 in which the ferrimagnetic garnet material is doped with suitable ions to provide electronic gain at the wavelength of the radiation propagating therein.