Optical waveguides – With optical coupler – Switch
Reexamination Certificate
1998-08-07
2001-07-31
Sanghavi, Hemang (Department: 2872)
Optical waveguides
With optical coupler
Switch
C385S017000, C385S018000, C385S019000, C385S020000
Reexamination Certificate
active
06269201
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to fiber optical switches, and more particularly concerns a one-by-N fiber optical switch.
BACKGROUND OF THE INVENTION
For purposes of convenience and economics, it is often desirable to employ switches in optical networks, so that either a single optical signal can be shared between two or more users or a single user can choose from a variety of optical signals without the added expense and complexity of installing additional hardware. In particular, one-by-four fiber optical switch is used to change the path of an optical signal between a single input optical fiber connected to a transmitting location and four different output optical fibers connected to receiving locations, thereby allowing four different users to access an optical signal originating from a single source. Similarly, an output common one-by-four fiber optical switch is used to change the path of an optical signal between four different input optical fibers connected to transmitting locations and a single output optical fiber connected to a receiving location, thereby allowing a single user to access four different optical signals.
In optical fiber switches, either multi-mode fiber or single-mode fiber can be used. Regardless of what type of fiber is used, it has always been very difficult to align optical paths when bare fiber is used. Because fiber cores are so small, a misalignment of a few micrometers can cause large insertion losses (i.e., the loss in signal transmission). This is especially true when using single-mode fiber.
This misalignment problem has been addressed to some extent in the prior art through the use of a Grade Refractive Index (GRIN) lens. The GRIN lens makes the fiber act as if its core diameter has been enlarged to the size of the GRIN lens diameter, thereby making the fiber core diameter behave as if it was at least ten to one-hundred times larger. As a result, insertion losses will be minimized when there is a few micrometers of misalignment between the optical signal from the input fiber to the output fiber. Inherent misalignments cannot be corrected through the use of a GRIN lens.
Currently, there are two different technologies used to make optical fiber switches (exclusive of the integrated optic switch). A first is known as moving fiber. In this technology, either the input optical fibers (or the output optical fibers) are actually reoriented to switch the optical signal between outputs, or vice versa. The second is known as moving prism or mirror. In this technology, the refractive medium (i.e., the prism) or the mirror is reoriented to switch the optical signal between outputs while the fibers do not move. These prior art technologies, however, have suffered from unacceptable insertion losses and low stability (e.g. alignment problems).
An example of an optical system that uses a moving reflector assembly is disclosed in U.S Pat. No. 5,436,986 and co-pending application, U.S. Ser. No. 08/451,527, by the same inventor as this application. Both are hereby incorporated by reference in their entirety.
SUMMARY OF THE INVENTION
The present invention overcomes the problems and disadvantages of the prior art through the use of unique arrangements of high-quality reflective surfaces and optical fibers. At least one of a plurality of optical fibers is optically aligned with a common optical fiber to create a one-by-N optical switch. The one-by-N optical switch can either be employed as an input common optical switch or an output common optical switch. An N-by-N optical switch can be created by cross-connecting a plurality of input common optical switches with an equal plurality of output common optical switches.
In accordance with the present inventions, a one-by-N optical switch includes a common optical fiber, an opposing optical fiber, and a plurality of optical fibers, and a base on which the optical fibers are fixably mounted. The opposing optical fiber is opposite to and collinear with the common optical fiber. The plurality of optical fibers are perpendicular to the common optical fiber. An equal plurality of reflector assemblies respectively associated with the plurality of optical fibers are pivotably mounted to the base. Each of the reflector assemblies are movable between a first position and a second position. When one of the reflector assemblies are in a first position, an optical signal emerging from the common optical fiber is deflected by the reflector assembly into the associated optical fiber, and vice versa; and when all of the reflector assemblies are in second positions, an optical signal emerging from the common optical fiber travels to the opposing optical fiber without deflection, and vice versa.
The one-by-N optical switch further includes a plurality of reflector assembly movers respectively and magnetically coupled to the plurality of reflector assemblies. Each reflector assembly mover creates an electrically induced magnetic force that moves the associated reflector assembly between its first position and a second position. Alternatively, each reflector assembly mover creates a passive magnetic force that tends to maintain the associated reflector assembly in its first position and/or second position.
In accordance with the present inventions, another one-by-N optical switch includes a common optical fiber, a first series of optical fibers, and a base on which the optical fibers are fixably mounted. The first series of optical fibers can be characterized as first intermediate optical fibers and a first terminal optical fiber. The first intermediate optical fibers includes one or more optical fibers. The first intermediate optical fibers are parallel to and adjacent the common optical fiber. The first terminal optical fiber is parallel to and adjacent the first intermediate optical fibers.
The one-by-N optical switch further includes a common reflector assembly associated with the common optical fiber, first intermediate reflector assemblies associated with the first intermediate optical fibers, and a first terminal reflector assembly associated with the first terminal optical fiber. The first intermediate reflector assemblies are pivotably mounted to the base. The common reflector assembly and first terminal reflector assembly can either be pivotably or fixably mounted to the base. The common reflector assembly is placed in a first position to optical engage the first series of optical fibers with the common optical fibers such that an optical signal emerging from the common optical fiber is deflected towards the first series of optical fibers, and vice versa. The first intermediate reflector assemblies are movable between a first position and a second position. When one of the first intermediate reflector assemblies are in a first position, an optical signal deflected from the common reflector assembly is further deflected into the associated first intermediate optical fiber. The first terminal reflector assembly is in a first position such that when all of the first intermediate reflector assemblies are in second positions, an optical signal deflected from the common reflector assembly is further deflected into the first terminal optical fiber, and vice versa.
The one-by-N optical switch can also include a second series of optical fibers fixably mounted to the base. The second series of optical fibers can be characterized as second intermediate optical fibers and a second terminal optical fiber. The second intermediate optical fibers include one or more optical fibers. The second intermediate optical fibers are parallel to and opposite the common optical fiber. The second terminal optical fiber is parallel to and adjacent the second intermediate optical fibers.
A common trans-series reflector assembly, second intermediate reflector assemblies and a second terminal reflector assembly are respectively associated with the common optical fiber, second intermediate optical fibers, and the second terminal optical fiber. The second intermediate reflector assemblies are pivotably mounted to the base. The comm
Ko Chun-Ming
Tsai Jian-Hung
Lightech Fiberoptics Inc.
Lyon & Lyon LLP
Sanghavi Hemang
LandOfFree
Multi-channel fiber optical switch does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Multi-channel fiber optical switch, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Multi-channel fiber optical switch will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2497452