Optical waveguides – With optical coupler – Switch
Reexamination Certificate
2001-04-04
2002-12-03
Lee, John D. (Department: 2874)
Optical waveguides
With optical coupler
Switch
C359S223100, C359S224200
Reexamination Certificate
active
06490384
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a light modulating system; and, more particularly, to an optical switching system for use in the light modulating system, wherein the optical switch provides 2-axes switching capability from fiber to fiber with deformable mirror arrays.
BACKGROUND OF THE INVENTION
Switching systems are well known in the communications field. In the telecommunications field the switching systems are used to route calls from point to point. In this regard, the switching systems may be embodied in a central office (CO) or an exchange, and such switching systems are often utilized for routing signals. Thus, a signal from a caller at a first endpoint passes through a local exchange (or central office) and perhaps several other Intermediate exchanges, in route to the destination or called endpoint.
Recently, certain optical devices have been developed, which allow certain limited multiplexing capability in the optical domain. For example, wavelength division multiplexing (WDM) technology offers a practical solution for multiplexing many high-speed channels at different optical carrier frequencies and transmitting them over a common fiber. As is known, WDM is conceptually similar to frequency division multiplexing in the electrical domain, except that a plurality of optical signals (of differing wavelength) are communicated through a common optical fiber. A significant limitation, however, to switching systems is observed at an exchange. When certain signals from incoming optical trunks are switched, or routed, to output trunks, these systems require an optical-electrical-optical conversation. This results in decreasing both the speed and traffic-handling capacity of networks as well as increasing the operational cost associated with the conversion process.
Several methods and structures of optical switching using micro-mechanical modulators have been proposed to direct optical signal from fiber to fiber in the networks.
In one method and structure, a reflective surface is supported by a flexible hinge or flange over addressing circuitry having two electrodes with a gap intervening therebetween, which is disclosed in U.S. Pat. No. 5,774,604, and entitled “USING AN ASYMMETRIC ELEMENT TO CREATE A 1×N OPTICAL SWITCH”. When one electrode is activated by application of a voltage, the surface will be selectively attracted toward that electrode as a result of electrostactic forces. In this way, the structure becomes an addressable 1×2 switch. Additionally, a stepped offset mirror is equipped and the position of the reflected beam becomes adjustable with more than one state, in such a way that the structure becomes a 1×N switch.
Another method is shown in U.S. Pat. No. 5,208,880, entitled “MICRODYNAMICAL FIBER-OPTIC SWITCH AND METHOD OF SWITCHING USING SAME”. A mirror is mechanically coupled to a meander piezoelectric actuator by an actuating arm such that the mirror is displaced along a mirror displacement path in correspondence to deflection of the meander piezoelectric actuator. In 1×N optical switch, the mirror is oriented at substantially 45 degrees such that light reflecting path is substantially perpendicular to incident light.
However, there are certain drawbacks associated with the methods described above. The structures only enable a 1×N switching capability. In other words, the methods using the above structures fail to provide switching capability in case that 2-axes switching is required for utilizing a multiple input channel.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide an optical switching system for obtaining 2-axes switching capability from fiber to fiber by using arrays of M×N deformable mirrors, wherein M and N are predetermined integers.
In accordance with an aspect of the present invention, there is provided an optical switching system comprising: an input part for receiving optical signals from outside; at least two modulators, each of the modulators being involved in modulating one-directional optical paths of the optical signals; and an output part for routing the optical signals to outside.
In accordance with another aspect of the present invention, there is provided an optical switching system comprising: an input part including an array of input optical fibers, each of input optical fibers being disposed to receive an optical signal from outside; a first modulator, for determining a first-directional address of the optical signal, including an array of first deformable mirrors and a first reflector, each of the input optical fibers having an address that corresponds to a first deformable mirror having the same address on a one-to-one basis; a second modulator, for determining a second-directional address of the optical signal, including an array of second deformable mirrors and a second reflector; and an output part including an array of output optical fibers, each of the output optical fibers disposed to transmit the optical signal to outside and having an address that corresponds to a second deformable mirror having a same address on a one-to-one basis.
In accordance with still another aspect of the present invention, there is provided an optical switching system comprising: an input part including an array of M×N input optical fibers, each of input optical fibers being disposed to receive an optical signal from outside; a first modulator, for determining a first-directional address of the optical signal, including an array of M×N first deformable mirrors and an array of M×N first compensating deformable mirrors, each of the input optical fibers having an address that corresponds to a first deformable mirror having the same address on a one-to-one basis; a second modulator, for determining a second-directional address of the optical signal, including an array of M×N second deformable mirrors; and an output part including an array of M×N output optical fibers and an array of M×N second image lenses, each of the output optical fibers disposed to transmit the optical signal to outside and having an address that corresponds to a second deformable mirror having the same address on a one-to-one basis, and each of the imaging lenses collimating the optical signal onto an output optical fiber, wherein M and N are predetermined integers, respectively.
In accordance with still another aspect of the present invention, there is provided an optical switching system comprising: an input/output part including an array of M×N input optical fibers and an array of M×N image lenses, each of the input/output optical fibers being disposed to receive an optical signal and transmit it to outside; a first modulator, for determining a first-directional address of the optical signal, including an array of M×N first deformable mirrors and an array of M×N first compensating deformable mirrors; and a second modulator, for determining a second-directional address of the optical signal, including an array of M×N second deformable mirrors and an array of M×N second compensating deformable mirrors, wherein M and N are predetermined integers, respectively.
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Bacon & Thomas
Knauss Scott A
Lee John D.
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