Optical switch

Details Optical switch Optical switch

2002-09-03

2004-09-21

Glick, Edward J. (Department: 2882)

Optical waveguides

With optical coupler

Switch

C385S025000, C385S036000

Reexamination Certificate

active

06795604

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to optical switches used in fiber communication and optical network technology, and particularly to a mechanical optical switch with a prism as a switch element.
2. Description of Prior Art
For purposes of convenience and economy, 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.
Optical switches can be classified as mechanical optical switches or as non-mechanical optical switches. Mechanical optical switches realize changes in lightpaths by moving optical fibers or elements using principles of mechanics or electromagnetism.
Referring to
FIGS. 9A and 9B
, U.S. Pat. No. 6,154,586 discloses an optical switch
99
which, in a first state, reflects an input light beam from an input port
82
to a reflection output port
83
, and in a second state, transmits an input light beam from the input port
82
to a transmission output port
84
. The optical switch
99
further comprises a block
81
made of a light transparent substrate, which has a reflective surface
811
. A reflective cavity
86
and a transmissive cavity
87
are defined in the block
81
, and are spaced by a light transparent diaphragm
85
. The reflective cavity
86
and the transmissive cavity
87
are respectively filled with a reflective and transmissive fluid. The optical switch
99
further comprises an actuator
7
connected with the transmissive cavity
87
by a connecting channel
71
. The actuator
7
controls the light transparent diaphragm
85
contacting with or detaching from the reflective surface
811
.
Referring to
FIG. 9A
, the optical switch
99
is at the first state, and the reflective fluid covers the reflective surface
811
of the block
81
. The input light beam from the input port
82
is incident on the reflective surface
811
at an angle which is equal to or greater than a critical angle determined by the refractive indices of the reflective surface
811
and the reflective fluid of the reflective cavity
86
. The light beam is totally reflected to the reflection output port
83
. Referring to
FIG. 9B
, the optical switch
99
is at the second state, and the transparent diaphragm
85
contacts with the reflective surface
811
. The input light beam from the input port
82
is incident on the reflective surface
811
at an angle which is smaller than a critical angle determined by the refractive indices of the reflective surface
811
and the transparent diaphragm
85
. The light beam is transmitted to the transmission output port
84
through the block
81
.
However, the optical switch above mentioned has some shortcomings. First, the reflective cavity
86
and the transmissive cavity
87
of the block
81
are filled with fluid. In order to prevent fluid from leaking out of the cavities
86
,
87
, the block
81
must have good seals, thus increasing the cost of the optical switch. Second, when the transparent diaphragm
85
contacts with the reflective surface
811
, residual fluid is unavoidably left between the transparent diaphragm
85
and the reflective surface
811
, thus reducing performance of the optical switch.
An improved optical switch having good performance and low cost is desired.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide an optical switch having good performance and low cost.
To achieve the above objects, an optical switch in accordance with the present invention comprises an input device, a reflection output device, a transmission output device, a prism and a rotation device. The input and reflection output devices are rotatable around the prism between a first position and a second position. The prism has a reflective surface to effect optical switching. When the input and reflection output devices are at a first position, an input light beam from the input device passes through the reflective surface of the prism, and is output through the transmission output device. When the input and reflection output devices are at a second position, the input light beam from the input device is incident on the reflective surface of the prism at an angle which is equal to or larger than a critical angle of the prism. The input light beam is totally reflected by the reflective surface of the prism, and is output through the reflection output device.


REFERENCES:
patent: 4378144 (1983-03-01), Duck et al.
patent: 5546180 (1996-08-01), Garel-Jones et al.
patent: 5781672 (1998-07-01), Cutts

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