Optical waveguides – With optical coupler – Input/output coupler
Reexamination Certificate
1998-10-02
2001-09-04
Healy, Brian (Department: 2874)
Optical waveguides
With optical coupler
Input/output coupler
C359S575000, C385S014000
Reexamination Certificate
active
06285813
ABSTRACT:
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
TECHNICAL FIELD
This application relates to the field of optical coupling, and more particularly, to the field of diffractive grating in-coupling and out-coupling of guided optical waves.
BACKGROUND INFORMATION
Current communications systems are being stressed due to the ever increasing demand for greater bandwidth to handle evolving communications needs. More and more, telecommunications systems are evolving to meet these needs by employing optical signaling systems, which employ optical fiber and specialized optical circuits and components.
The creation of such optical components has become a time consuming and expensive proposition. The optical fibers and optical circuits manufactured today are microscopic in size, where typical optical waveguides feature a cross-section of but a few microns in diameter.
Due to the size of optical waveguides and optical circuitry and other factors, current processes employed in their manufacture can be very costly and labor intensive. With regard to particular components employed to couple a guided wave from one optical waveguide to a detector or another waveguide, or to couple a light source to a waveguide, this is especially the case. In these couplers, oftentimes a lens is employed to focus the exiting light so as to allow the light to enter a second waveguide without obstruction or loss. Positioning of such a lens is quite labor intensive, as are the subsequent steps of packaging the overall device, translating into a very high cost. This high cost impedes the overall creation of optical communications systems. Consequently, there is a need for a diffractive coupler that can be manufactured simply, thereby allowing such components to be manufactured at significantly reduced cost with low labor requirements.
BRIEF SUMMARY OF THE INVENTION
The present invention entails a volume grating for use in an optical coupler which comprises a grating-cover interface plane having a predetermined surface grating pattern with a decreasing surface grating period along a waveguide light propagation direction in the volume grating, with a plurality of slanted grating fringes having a variable slant angle along the waveguide light propagation direction to focus coupled light in a first dimension with a predetermined light intensity profile along the grating-cover interface plane of the volume grating. In addition, the predetermined surface grating pattern further includes an increasing radius of curvature along the waveguide light propagation direction to focus the light in a second dimension.
The present invention may also be viewed as a method for coupling light from a waveguide to a focused line or spot. This method comprises the steps of directing a laser light beam into a waveguide having a volume grating, coupling the laser light with a plurality of slanted grating fringes having a variable slant angle along the waveguide light propagation direction, and focusing the laser light with a predetermined surface grating pattern having a decreasing surface grating period along a waveguide light propagation direction in the volume grating. The method further comprises the step of focusing the laser light with fringes having an increasing radius of curvature along the waveguide light propagation direction in the volume grating.
Another embodiment of the present invention entails a system for creating a volume grating for use in an optical coupler, the system comprising a pair of mutually coherent laser beams which are conditioned to create an interference pattern in a recording material. This interference is characterized by a cross section having a surface pattern with a decreasing surface period along the waveguide light propagation direction in the recording material, and slanted fringes having a variable slant angle along the waveguide light propagation direction. The cross-section surface pattern may be further characterized by an increasing radius of curvature along the waveguide light propagation direction.
The present invention may further be viewed as a method for creating a volume grating for use in an optical coupler which is comprised of the steps of generating a laser beam and splitting the laser beam into a pair of mutually coherent laser beams. Next, the pair of mutually coherent laser beams are directed into an optical coupling component which is configured to optically couple the pair of laser beams to a recording material. Finally, the pair of mutually coherent laser beams are focused to create an interference pattern in the recording material with a cross-section having a surface pattern with a decreasing surface period along a waveguide light propagation direction in the volume grating, and a plurality of slanted fringes having a variable slant angle along the waveguide light propagation direction. The method may further comprise the step of conditioning the pair of mutually coherent laser beams creating the interference pattern such that the surface pattern is further characterized by an increasing radius of curvature along the waveguide light propagation direction.
Other features and advantages of the present invention will become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional features and advantages be included herein within the scope of the present invention, as defined by the claims.
REFERENCES:
patent: 4978187 (1990-12-01), Minemura et al.
patent: 5009484 (1991-04-01), Gerritsen
patent: 5033812 (1991-07-01), Yoshida et al.
patent: 5101459 (1992-03-01), Sunagawa
patent: 5436991 (1995-07-01), Sunagawa et al.
patent: 5469518 (1995-11-01), Song et al.
Huang et al., “Holographic Bragg grating input-output couplers for polymer waveguides at an 850-nm wavelength”, Applied Optics, vol. 36, No. 6, pp. 1198-1203, Feb. 1997.*
Oh et al., “Integrated-Optic Focal-Spot Intensity Modulator Using Electrooptic Polymer Waveguide”, Journal of Lightwave Technology, vol. 12, No. 9, pp. 1569-1576, Sep. 1994.*
Waldhausl et al., “Efficient focusing polymer waveguide grating couplers”, Electronics Letters, vol. 33, pp. 623-624, Mar. 1997.*
Schultz, et al., “Design of a High-Efficiency Volume Grating Coupler Coupler for Line Focusing,” Applied Optics, vol. 37, pp. 2278-2287, Apr. 1998.
W. Driemeier, “Bragg-Effect Grating Couplers Integrated in Multicomponent Polymeric Waveguides,” Optics Letters, vol. 15, pp. 725-727, Jul. 1, 1990.
Huang, et al., “Holographic Bragg Grating Input-Output Couplers for Polymer Waveguides at 850-nm Wavelength, ” Applied Optics, vol. 36, pp. 1198-1203, Feb. 1997.
Jones, et al., “Rectangular Characteristic Gratings for Waveguide Input and Output Coupling,” Applied Optics, vol. 34, pp. 4149-4158, Jul. 10, 1995.
Weiss, et al., “Coupling and Waveguiding in Photopolymers,” in Proc. SPIE, vol. 3132, pp. 136-143, 1997.
Larrson, et al., “Grating Coupled Surface Emitters with Enhanced Surface Emission Efficiency,” in Proc SPIE, vol. 2398, pp. 21-23, 1995.
A. Alphones, “Double Grating Coupler on a Grounded Dielectric Slab Waveguide,” Optics Communications, vol. 92, pp. 35-39, Aug. 15, 1992.
Avrutskii, et al., An Efficient Grating Coupler, Zhurnal Tekhnicheskoi Fiziki, vol. 59, pp. 61-65, Jul. 1989.
Avrutskii, et al., “Unidirectional Coupling of Radiation out of a Composite Dielectric Waveguide,” Sov. J. Quantum Electron., vol. 19, pp. 225-228, Feb. 1989.
Avrutsky, et al., “High-Efficiency Single-Order Waveguide Grating Coupler,” Optics Letters, vol. 15, pp. 1446-1448, Dec. 1990.
Brazas, et al., “High-Efficiency Input Coupling into Optical Waveguides Using Gratings with Double-Surface Corrugation,” Applied Optics, vol. 34, pp. 604-609, Feb. 1, 1995.
L.Li, “Analysis of Planar Waveguide Grating Couplers with Double Surface Corrugations of Identical Period,” Optics Communications, vol. 114, pp. 406-412, Feb. 15, 1995.
Eriksson, et al., “Highly Efficient Grating-Coupled Surface-Emitters with Single Outcoupling Elements,” IEEE Photonics Technology Letters, vol. 7, pp
Gaylord Thomas K.
Glytsis Elias N.
Hartman Nile F.
Schultz Stephen M.
Connelly-Cushwa Michelle R.
Georgia Tech Research Corporation
Healy Brian
Thomas Kayden Horstemeyer & Risley
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