Optical waveguides – Directional optical modulation within an optical waveguide
Reexamination Certificate
2000-07-07
2002-06-04
Sanghavi, Hemang (Department: 2874)
Optical waveguides
Directional optical modulation within an optical waveguide
C385S016000, C385S036000
Reexamination Certificate
active
06400855
ABSTRACT:
TECHNICAL FIELD
The present invention generally relates to optics, and more particularly, to an N×N optical switching array device and system.
BACKGROUND
The increasing demand for high-speed broadband communications as resulted in a rapid increase in fibre optic communications systems which require faster and more reliable components to interconnect associated optoelectronic devices of a network. These components may include devices for steering light beams through light transmissive mediums at specific angles. Currently, devices use opto-mechanical or electro-optical technology to steer light beams to a specified angle.
Opto-mechanical technology for signal channeling or steering have several disadvantages. For example, opto-mechanical devices are bulky and slow due to the mechanical scanning devices employed for optical signal distribution. In addition, degradation of mechanical components often makes these devices less reliable. Opto-mechanical devices also require complicated three-dimensional angular alignment, resulting in a low tolerance to harsh environments. Furthermore, due to optical mode mismatching, opto-mechanical devices often fail to provide low-loss coupling among devices such as laser diodes, optical modulators, waveguide splitters, single-mode optic fibers, multi-mode optic fibers, and optical detectors.
Other conventional deflection devices use electro-optical technology to steer light beams. Since these devices do not require moving parts, they are generally faster and more reliable than opto-mechanical devices. One type of electro-optic (EO) deflector uses bulk crystals for beam steering. These devices, however, are generally large and heavy and require higher driving voltages (usually in the kV range). More compact devices with lower operating voltages include metallic electrodes on two sides of thin electro-optic crystals. For example, multichannel phase-array devices employ the electro-optical properties of crystals to achieve phase modulation. These devices have the advantage of low operating voltages (around 32 V, for example), but they typically suffer from the presence of multiple grating lobes.
Nonmechanical beam deflectors are of interest for many military and commercial applications such as laser tracking and targeting, optical data storage, optical switching, laser printing, scanning, optical sensing, optical computing, and laser control. Current beam steering systems are very complex, costly, and too large for most airborne/space applications. Devices for controlling the direction of a laser beam have been limited in the past, and restricted almost entirely to such methods as galvanic mirror, and acousto-optic and electro-optic beam deflection. These methods suffer from various problems including, high driving power, limited speed, low resolution, and complex fabrication. One of the most promising technologies to date for scanning a laser beam without any moving parts is electro-optical beam deflection. Additionally, electro-optic beam deflectors often include some advancements using domain reversal in ferroelectric crystals. As such, a major drawback of this conventional system is the demand of very high driving voltages (>1000 V).
Typical electro-optic deflectors also do not meet the demand imposed by most aircraft/space applications. The deflection angle of conventional electro-optic devices is too small to provide large scanning angles. Additionally, the driving voltage is high, which contributes to the possibility of a dielectric breakdown between closely-spaced electrodes. Further, the switching speed of these devices is typically less than the gigahertz level and the fabrication and technical development of these devices are complex and/or impose difficult operating processes.
SUMMARY
In accordance with teachings of the present invention, a method, system and apparatus are provided for deflection and switching of optical signals.
In accordance with one aspect of the present invention an optical switching device for communicating optical signals in a communications network is disclosed. The device includes a plurality of inputs optically coupled to at least one thermo-optic array and a plurality of outputs optically coupled to the thermo-optic array wherein the plurality of inputs and outputs cooperate with each other to communicate at least one optical signal via the thermo-optic array.
In accordance with another aspect of the present invention a network communications system for communicating optical signals is disclosed. The system includes a communication medium operable to communicate optical signals, a plurality of optical waveguides associated with the communications medium and a switching device operable to communicate signals from an initiating point to a selected destination point. The system preferably includes a switching device having an input optically coupled to at least one of the plurality of optical waveguides and an output optically coupled to at least one of the plurality of optical waveguides. the optical waveguides are preferably coupled with a thermo-optic array whereby the thermo-optic array is operable to deflect an optical signal from the initiating point to the selected destination point.
In accordance with another aspect of the present invention, an optical switching device for communicating optical signals is disclosed. The device includes a plurality of optical inputs operable to communicate optical signals and a plurality of optical outputs selectively coupled to the optical inputs. At least one thermo-optic array is optically coupled to the plurality of optical inputs and the plurality of optical outputs. The thermo-optical array is preferably operable to selectively deflect an optical signal from one of the plurality of optical inputs to one of the plurality of optical outputs in response to a temperature differential.
In accordance with another aspect of the present invention, an optical switching structure for communicating optical signals is provided. The structure includes a first cladding layer coupled to a substrate and an optical switching layer coupled to the cladding layer. The optical switching layer includes a first and second material forming an array. The structure further includes a thermal element operable to alter a temperature associated with the optical switching layer and coupled to the optical switching layer.
It is a technical advantage of the present invention to provide an optical deflection device having large thermo-optic coefficients in combination with low thermal conductivities resulting in the device having relatively low power consumption.
It is a further technical advantage of the present invention to utilize polymer technologies for large-scale integration of optical communication and switching devices.
It is another technical advantage of the present invention to provide thin-film waveguides including low power consumption optical polymers having desirable thermo-optic characteristics for communicating optical signals.
It is another technical advantage of the present invention to provide an optical device having advantageous geometric features, such as triangular, to provide waveguide prisms.
It is a further technical advantage of the present invention to provide alternatively a waveguide having positioned polymer and silica materials within, for example, a three layer planar waveguide.
It is another technical advantage of the present invention to provide an N×N optical waveguide array operable to efficiently switch optical signals without using mechanical devices or requiring optical to electrical conversions.
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patent:
Li Bulang
Tang Suning
Baker & Botts L.L.P.
Knauss Scott
Radiant Photonics, Inc.
Sanghavi Hemang
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