Optical waveguides – With optical coupler – Switch
Utility Patent
1999-09-03
2001-01-02
Phan, James (Department: 2872)
Optical waveguides
With optical coupler
Switch
C385S016000, C385S020000, C385S021000, C385S023000
Utility Patent
active
06169827
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a micro-optic switch used for transmitting optical signals between optical fibers. More particularly, the invention pertains to a micro-optic switch using polymer structures to position a microactuator and optical fibers on a substrate so that the microactuator can move an optical fiber cantilevered between two fixed fibers to transmit optical signals between either one of the fixed fibers and the cantilever fiber. Using polymers instead of micromachined structures to position components of the switch reduces cost and simplifies assembly. The invention further provides processes for producing a micro-optic switch and for switching the path of an optical signal.
2. Description of the Related Art
Recent developments in the area of optical communications have provided a large number of devices for the control and routing of light. These devices can be characterized as passive devices, those which serve only to route the propagation of light along a particular path, and active devices, those which control some function of the propagating light, such as the path along which the light propagates. Optical fibers have been the medium of choice in the field of optical communications for long distance propagation of light due to their excellent transmission characteristics and ability to be fabricated in lengths of many kilometers.
Light propagates through the core region of optical fibers and these core regions can be as small as a few microns in diameter. A key component in a reliable optical fiber communication system is an optomechanical switch which is optically connected to light conducting fibers and enables different communication paths to be interconnected. For example, U.S. Pat. No. 5,479,541 discloses an optical switch having a first optical fiber which forms an optical path with additional optical fibers, wherein lenses are attached to the ends of each optical fiber to collimate light beams and assist in the transmission optical data between fibers. Also, U.S. Pat. No. 4,204,744 discloses a switch for optically connecting light conducting fibers utilizing a magnetic sleeve adjacent to a free moving fiber which enables the alignment of a pole fiber with at least one throw fiber.
It is known in the art to produce metal micro-electro-mechanical-systems (MEMS) and micro-optical-electro mechanical systems (MOEMS) including components of micro-optic switches by the LIGA process. LIGA is a German language acronym for Lithographie, Galvanoformung and Abformung, the main steps of a process employing X-ray lithography, electro forming and plastic molding to produce microcomponents of a micro-optic switch. The original idea of LIGA-MEMS was to make metal tooling from which mass replicates could be made from plastic. Since switches using electrostatics or electromagnetics require metal parts, these parts are made by the electro forming step. Polymer replicates are generally not used. Using LIGA-MEMS technology to fabricate micro-optic metal switch parts is an expensive process. In order to minimize the cost of a micro-optic switch, it is beneficial to make as much of the switch as possible with polymer components, and only use metal LIGA-MEMS components for those parts of the switch where they are necessary for actuation or to assure high levels of performance. The present invention provides such a low cost micro-optic switch having polymeric parts and a process by which the switch can be made.
The micro-optic switch of the present invention has the advantages of a MEMS device, such as small size, low power consumption, high speed, and excellent optical properties, without the high cost of a device made completely from LIGA-MEMS technology. The switch uses lithographically defined polymer structures to position both the MEMS components, such as actuators, and the ancillary components, such as optical fibers, which must interact with those MEMS components. Costs are reduced because only the portions of the switch which have special functions, and therefore need to be made by MEMS processes, are not made of polymer. In addition, a variety of substrates may be used, and the substrate material can be tailored to reduce costs and provide additional stability. Furthermore, this approach provides for straightforward integration with other optic components such as polymer waveguides and filters.
SUMMARY OF THE INVENTION
The invention provides a micro-optic switch comprising:
a) a planar substrate;
b) at least one array comprising:
first and second optical fiber grippers on the substrate, each of the grippers having a central groove and the first and second optical fiber grippers being positioned such that the grooves are substantially collinear; and an optical fiber alignment bumper on the substrate having a central groove, being positioned such that the groove is substantially collinear with the grooves of the first and second optical fiber grippers;
c) at least two horizontally spaced throw optical fibers fixed in the groove of each second optical fiber gripper; and
d) at least one pole optical fiber fixed in each first optical fiber gripper such that it cantilevers over the substrate and extends at least part of the way through the groove of the alignment bumper, such that an end thereof is capable of alternate positioning in alignment with a complementary end of one of the throw fibers.
The invention also provides a process for producing a micro-optic switch comprising:
a) providing a planar substrate; and
b) forming at least one array comprising lithographically forming first and second optical fiber grippers on the substrate, each of the grippers having a central groove and the first and second optical fiber grippers being positioned such that the grooves are substantially collinear; and simultaneously lithographically forming an optical fiber alignment bumper on the substrate having a central groove, being positioned such that the groove is substantially collinear with the grooves of the first and second optical fiber grippers.
The invention further provides a process for switching the path of an optical signal which comprises:
A) providing a micro-optic switch comprising:
a) a planar substrate;
b) at least one array comprising:
first and second optical fiber grippers on the substrate, each of the grippers having a central groove and the first and second optical fiber grippers being positioned such that the grooves are substantially collinear; and an optical fiber alignment bumper on the substrate having a central groove, being positioned such that the groove is substantially collinear with the grooves of the first and second optical fiber grippers;
c) at least two horizontally spaced throw optical fibers fixed in the groove of each second optical fiber gripper;
d) at least one pole optical fiber fixed in each first optical fiber gripper such that it cantilevers over the substrate and extends at least part of the way through the groove of the alignment bumper, such that an end thereof is capable of alternate positioning in alignment with a complementary end of one of the throw fibers; and
e) means for alternately positioning the end of the pole optical fiber with an end of one of the throw fibers;
B) directing an optical signal through the pole optical fiber; and
C) alternately positioning the end of the pole optical fiber with an end of one of the throw fibers.
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Norwood, R.A., et al “Fast,low insertion loss optical switch using lithographically defined electromagnetic microactuators and polymeric passive alignment structures” Applied Physics Letters; vol. 73, No. 22; Nov. 30, 1998.
Nagaoka, Shinji, et al, “Compact Optomechanical Switches and their Applications in Optical Communications and Testing Systems” (
Emo Stephen M.
Holman Jason
Norwood Robert A.
Shacklette Lawrence W.
Honeywell International , Inc.
Phan James
Shudy, Jr. John G.
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