Optical waveguides – With optical coupler
Reexamination Certificate
2001-03-27
2004-09-07
Sanghavi, Hemang (Department: 2874)
Optical waveguides
With optical coupler
C385S024000, C385S046000, C385S016000, C385S045000, C385S131000, C385S037000
Reexamination Certificate
active
06788837
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to multiplexing/demultiplexing and switching signals and, more specifically, the present invention relates to multiplexing/demultiplexing and switching optical signals.
2. Background Information
The need for fast and efficient optical switches, multiplexors/demultiplexors, and other similar types of optical devices is increasing as Internet data traffic growth rate is overtaking voice traffic pushing the need for optical communications. Commonly used multiplexors/demultiplexors include diffraction gratings, thin-film filters, fiber Bragg gratings, and arrayed-waveguide gratings. Two commonly found types of optical switches are mechanical switching devices and electro-optic switching devices.
Mechanical switching devices generally involve physical components that are placed in the optical paths between optical fibers. These components are moved to cause switching action. Micro-electronic mechanical systems (MEMS) have recently been used for miniature mechanical switches. MEMS are popular because they are silicon based and are processed using somewhat conventional silicon processing technologies. However, since MEMS technology generally relies upon the actual mechanical movement of physical parts or components, MEMS are generally limited to slower speed optical applications, such as for example applications having response times on the order of milliseconds.
In electro-optic switching devices, voltages are applied to selected parts of a device to create electric fields within the device. The electric fields change the optical properties of selected materials within the device and the electro-optic effect results in switching action. Electro-optic devices typically utilize electro-optical materials that combine optical transparency with voltage-variable optical behavior. One typical type of single crystal electro-optical material used in electro-optic switching devices is lithium niobate (LiNbO
3
).
Lithium niobate is a transparent, material that exhibits electro-optic properties such as the Pockels effect. The Pockels effect is the optical phenomenon in which the refractive index of a medium, such as lithium niobate, varies with an applied electric field. The varied refractive index of the lithium niobate may be used to provide switching. The applied electrical field is provided to present day electro-optical switches by external control circuitry.
Although the switching speeds of these types of devices are very fast, for example on the order of nanoseconds, one disadvantage with present day electro-optic switching devices is that these devices generally require relatively high voltages in order to switch optical beams. Consequently, the external circuits utilized to control present day electro-optical switches are usually specially fabricated to generate the high voltages and suffer from large amounts of power consumption. In addition, integration of these external high voltage control circuits with present day electro-optical switches is becoming an increasingly challenging task as device dimensions continue to scale down and circuit densities continue to increase.
REFERENCES:
patent: 5862279 (1999-01-01), Amersfoort et al.
patent: 5862288 (1999-01-01), Tayag et al.
patent: 5933554 (1999-08-01), Leuthold et al.
patent: 6084992 (2000-07-01), Weber et al.
patent: 6144779 (2000-11-01), Binkley et al.
patent: 6222955 (2001-04-01), Lagali et al.
patent: 6253000 (2001-06-01), Madsen et al.
patent: 6292597 (2001-09-01), Lagali et al.
patent: 6374013 (2002-04-01), Whiteaway et al.
patent: 6456754 (2002-09-01), Augustsson
patent: 6603893 (2003-08-01), Liu et al.
patent: 2001/0022878 (2001-09-01), Saida et al.
patent: 2002/0159686 (2002-10-01), Madsen
Bachmann, M., “General self-imaging properties in N × N multimode interference couplers including phase relations”,Applied Optics, vol. 33, No. 18, pp. 3905-3911, Jun. 20, 1994.
Smit, M.K., “PHASAR-Based WDM-Devices: Principles, Design and Applications”,IEEE Journal of Selected Topics in a Quantum Electronics, vol. 2, No. 2, pp. 236-250, Jun. 1996.
Soldano L.B., “Optical Multi-Mode Interference Devices Based on Self-Imaging: Principles and Applications”,Journal of Lightwave Technology, vol. 13, No. 4, pp. 615-627, Apr. 1995.
Kareenahalli, S., “Experimental Confirmation of Phase Relationships of Multimode Interference Splitters Using a Shearing-Type Near-Field Sagnac Interferometer”,IEEE Photonics Technology Letters, vol. 9, No. 7., pp. 937-939, Jul. 1997.
Rasmussen, T., “Design and Performance Evaluation of 1-by-64 Multimode Interference Power Splitter for Optical Communications”,Journal of Lightwave Technology, vol. 13, No. 10., pp. 2069-2074, Oct. 1995.
Rajarajan, M., “Accurate Analysis of MMI Devices with Two-Dimensional Confinement”,Journal of Lightwave Technology, vol. 14, No. 9, Sep. 1996.
Lorenzo, R.M., “Improved self-imaging characteristics in 1×N multimode couplers”,IEE Proc.-Optoelectron., vol. 145, No. 1, Feb. 1998.
Liu Ansheng
Paniccia Mario J.
Blakely , Sokoloff, Taylor & Zafman LLP
Sanghavi Hemang
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