Optical: systems and elements – Optical modulator – Light wave directional modulation
Reexamination Certificate
2002-04-03
2003-10-28
Sugarman, Scott J. (Department: 2873)
Optical: systems and elements
Optical modulator
Light wave directional modulation
C359S241000, C359S302000
Reexamination Certificate
active
06639712
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to electromagnetic radiation control devices. More specifically, the present invention relates to a method and apparatus for configuring and tuning crystals for switching and filtering of electromagnetic radiation.
2. Description of the Related Art
In communications systems using optical multiplexing such as dense wavelength, division multiplexing (DWDM), wavelength division multiplexing (WDM), time division multiplexing (TDM) and the like, the distribution of optical information is facilitated by the use of components such as fiber optic gratings, interferometers, various types of filters and the like. Traditional optical components, which are fabricated in plastic, semiconductor, or glass, are largely fixed in their optical properties by their rigid, essentially permanent structures. Thus, in this context, the distribution of optical information is also fixed and the service provider is unable to change the configuration of the DWDM, WDM or TDM format, e.g., distribution, without physically changing the communications system.
One type of photonic crystal known in the art comprises a glass or semiconductor substrate having a plurality of cylindrical apertures formed therethrough in a pattern. Some or all of the cylindrical apertures, such as pillars can be filled with a material having a refractive index different from the refractive index of the substrate.
As light is injected into one end of the substrate, the light interacts with the pillars. The light, as it propagates through the crystal, will be split into multiple paths that constructively and deconstructively interfere with one another to effectively filter the light as it passes through the crystal. For example, a particular bandwidth of light propagates through the filter and other wavelengths of light are either reflected or absorbed within the crystal structure. Generally, the spacing of the pillars and their refractive indices defines a filter that reflects a certain bandwidth of wavelengths of light. The pillars may be filled with gas, fluid or solid materials having various refractive indices. Crystal structures of this type are formed for a specific use and filter a specific wavelength of light and are not reconfigurable in a selective manner. As such, the crystals are used in applications where a fixed filter is necessary or desired.
Therefore there is a need in the art for a method and apparatus for configuring and tuning a photonic crystal.
SUMMARY OF THE INVENTION
The present invention is a method and apparatus for configuring and tuning a crystal by selectively controlling a fluid supplied to a plurality of nodes formed in a substrate. The apparatus comprises a substrate having at least one node that can be selectively supplied with a fluid that changes a material property of the node. The material property may include refractive index, magnetic permeability, inducible refractive index, absorption and the like. The node may be a spherical cavity in a three-dimensional structure, a cylindrical aperture in a two-dimensional structure, or a cavity in a one-dimensional structure. The node or nodes within the substrate are coupled to a fluid distribution assembly that selectively alters the material property of the node(s). The material property may be changed by moving the fluid, or a material in a fluid, using electrohydrodynamic pumping, electroosmotic pumping, electrophoresis, thermocapillarity, electrowetting or electrocapillarity. Such crystal structures can be used to switch or filter electromagnetic radiation such as light or microwaves.
REFERENCES:
patent: 6130969 (2000-10-01), Villeneuve et al.
patent: 2002/0051275 (2002-05-01), Tokushima
patent: 2002/0071646 (2002-06-01), Eggleton et al.
B. Nelson et al., “Use of a dielectric stack as a one-dimensional photonic crystal for wavelength demultiplexing by beam shifting”, Optics Letters, vol. 25, No. 20, Oct. 15, 2000.
M. Loncar, T. Doll et al., “Design and Fabrication of Silicon Photonic Crystal Optical Waveguides”, Journal of Lighwave Technology, vol. 18, No. 10, Oct. 2000 p. 1402-1411.
M. Bayindir et al., “Photonic-crystal-based beam splitters”, Applied Physics Letters, vol. 77, No. 24, Dec. 11, 2000, p. 3902-3904.
M. Tokushima et al., “Lightwave propagation through a 120° sharply bent single-line-defect photonic crystal waveguide”, Applied Physics Letters, vol. 76, No. 8, Feb. 21, 2000, p. 952-954.
J. Yonekura et al., “Analysis of Finite 2-D Photonic Crystals of Columns and Lightwave Devices Using the Scattering Matrix Method”, Journal of Lightwave Technology, vol. 17, No. 8, Aug. 1999, p. 1500-1508.
G. Tayeb et al., “Rigorous tehoretical study of finite-size two-dimensional photonic crystals doped by microcavities”, J. Opt. Soc. of America, vol. 14, No. 12, Dec. 1997, p. 3323-3332.
M. Pollack et al., “Electrowetting-based actuation of liquid droplets for microfluidic applications”, Applied Physics Letters, vol. 77, No. 11, Sep. 2000, pp. 1725-1726.
M.W.J. Prins et al., “Fluid Control in Multichannel Structures by Electrocapillary Pressure”, Science, vol. 291, Jan. 2001, pp. 277-280.
H. Kosako et al., “Superprism Phenomena in Photonic Crystals: Toward Microscale Lightwave Circuits”, Journ. of Lightwave Technology, vol. 17, No. 11, Nov. 1999, p. 2032-2038.
H-B Lin, “Two-Dimensional photonic bandgap optical limiter in the visible”, Optics Letters, vol. 23, No. 2, Jan. 1998, p. 94-96.
H-B Lin et al., “Observation of two-dimensional photonic band bahavior in the visible”, Applied Physics Lett. 68 (21) May 20, 1996, pp. 2927-2929.
A. Rosenberg et al., “Photonic band-structure effects in the visible and near ultraviolet observed in solild-state dielectric arrays”, Appl. Phys. Letter 69 (18), Oct. 1996, p. 2638-2640.
J. Shirk, “Protecting the War Fighter's Vision in a Laser-Rich, Battlefield Environment”, Optics & Photonics News, Apr. 2000, pp. 19-23.
B. Gralak et al., “Anomalous refractive properties of photonic crystals”, J. Optical Society of America, vol. 17, No. 6, Jun. 2000, pp. 1012-1020.
S. McBride et al., “Electrohydrodynamic Pumps for High-Density Microfluidic Arrays”, Proceedings of the Micro TAS 98 Workshop, Canada, Oct. 1998, pp. 45-48.
Abeles Joseph Hy
McBride Sterling Eduard
Zanzucchi Peter J.
Burke William J.
Hanig Richard
Sarnoff Corporation
Sugarman Scott J.
LandOfFree
Method and apparatus for configuring and tuning crystals to... 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 apparatus for configuring and tuning crystals to..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for configuring and tuning crystals to... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3136760