Optical waveguides – With optical coupler – Switch
Patent
1997-02-18
1998-08-11
Palmer, Phan T. H.
Optical waveguides
With optical coupler
Switch
385 11, 385 31, 359322, 359256, G02B 626
Patent
active
057939055
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates in general to nonlinear integral and fiber optics and more specifically to completely optical switches and optical (optoelectronic) transistors.
BACKGROUND ART
In a heretofore-known method for switching unidirectional distributively-coupled waves having orthogonal polarizations, a powerful optical radiation (hereinafter referred to as "pumping") is fed to the Input of a birefringent nonlinear object (optical waveguide or crystal), featuring effective refractive indices of an ordinary and an extraordinary wave n.sub.0 and n.sub.e, respectively, and a cubic nonlinearity coefficient .theta., said radiation being characterized by an intensity >0.4.multidot..vertline.n.sub.0 -n.sub.e .vertline./.vertline..theta..vertline., a field (polarization) vector directed at an angle .pi./4 to the optical axis of said object, concurrently with feeding a linearly polarized optical signal radiation (hereinafter referred to as "signal"), said radiation having an intensity which is by at least one order of magnitude lower than the intensity of pumping and being polarized orthogonally to the pumping, and the intensity of said signal is varied within the zero and the maximum value. As a result, there is established a linear distributed coupling between the signal and the pumping, and the ratio between the intensity values of the waves of various polarizations at the output of said object is drastically changed (cf. "Quantum electronics", 1982, vol.9, No.11 /Radio i sviaz PH, Moscow/, pp.2296-2302, A. A. Maier, "Optical transistors and bistable elements based on nonlinear luminous transmission by systems with unidirectional coupled waves").
One prior-art device (JP 3-36407, Int. Cl. G02F 3/00, 1984) is known to comprise a polarizer, a birefringent crystal, and an analyzer at the output, the direction of polarization of an incident light as set by the polarizer, makes up an angle of .pi./4 with the axis of optical anisotropy of the crystal.
However, the aforesaid known method places limitation upon the value of the amplification factor of a variable signal and involves some difficulties in orienting the object.
BRIEF DESCRIPTION OF THE DRAWINGS
The present inventions Is illustrated by the following drawings, wherein:
FIG. 1 shows an X,Y orientation of polarization with respect to the principal optic axes X'Y' of the object.
FIG. 2 shows a graphic representation of the coefficient of transfer of pumping radiation power T.sub.x =I.sub.x /(I.sub.x0 +I.sub.y0) vs the standardized value of intensity of signal R.sub.x .ident.I.sub.x0 .vertline..theta..vertline./4.gamma., polarized orthogonally to the pumping, with R.sub.x <<R.sub.y .ident.I.sub.y0 .vertline..theta..vertline./4.gamma.=3; ##EQU1##
FIG. 3 is a cross-sectional view of a nonlinear birefringent optical waveguide 4 with a light-carrying laminar structure, e.g., of the type of GaAs-Ga.sub.x Al.sub.1-x As forming a multiplicity of quantum wells (MQW). h . . . h3--thickness values of layers from 0 to 10 microns;
FIG. 4 shows a distribution of an effective refractive index in a cross-section of the object 4 (e.g., a birefringent fiber guide);
FIG. 5 is a schematic view of a device for carrying into effect the proposed method of switching of optical radiations having orthogonal polarizations showing a general pattern with pumping polarization along the optical axis of the object 4.
FIG. 6 same as in FIG. 5, with pumping polarization normal to the optical axis of the object 4.
DISCLOSURE OF THE INVENTION
A positive technical result of the present invention is expressed in a higher of amplification factor of a change in the signal intensity and provision of favorable conditions for creating an optical transistor, as well as devices based thereon.
The foregoing technical result is attained due to the fact that in a known method for switching optical radiations having orthogonal polarizations, according to the invention, the polarization vector of a linearly polarized pumping, or of a signal polarized orthogonally to sai
REFERENCES:
patent: 4919522 (1990-04-01), Nelson
patent: 5090824 (1992-02-01), Nelson et al.
patent: 5305136 (1994-04-01), Smith
Quantum Electronics, 1982, vol. 9, No. 11, pp. 2296-2302.
Transactions of the Academy of Sciences of the USSR, Ser. Phys., 1984, vol. 48, No., 7, pp. 1441-1446.
Maier Alexandr Alexandrovich
Sitarsky Konstantin Yurievich
Maier Optical Research and Technologies GmbH
Palmer Phan T. H.
LandOfFree
Method and device for switching of optical radiations of orthogo does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and device for switching of optical radiations of orthogo, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and device for switching of optical radiations of orthogo will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-398367