Optical waveguides – With optical coupler – Switch
Reexamination Certificate
2000-03-10
2002-07-16
Ullah, Akm E. (Department: 2874)
Optical waveguides
With optical coupler
Switch
C385S016000
Reexamination Certificate
active
06421477
ABSTRACT:
TECHNICAL FIELD
This invention can be utilized for optical communications, and relates to an optical switch that changes the optical propagation path by producing a mechanical displacement of the end portion of an optical fiber. It relates in particular to an optical switch for alternately switching between two optical paths comprising a pair of optical fibers.
This invention also relates to an optical switch provided at an optical fiber branch-point. It can be utilized as an optical path changeover switch in fields such as optical communications and optical instrumentation, where an optical signal propagates through optical fibers. This invention also relates to the application of micro-machining technology to optical switches.
BACKGROUND TECHNOLOGY
Optical switches capable of changing the signal route by changing the path taken by an optical signal are required in telecommunication switching systems and the like. Technology is known for implementing a mechanical optical switch that causes the end portion of a movable optical fiber to oppose the end portion of either one of a pair of fixed optical fibers. With regard to this mechanical optical switch, technology is known for aligning the end portions of two opposing optical fibers by disposing the end portions of the two fibers in a single V-groove (for example, JP 8-20618 B, JP 6-273680 A, JP 6-208064 A and JP 6-265799 A).
Such optical switch technology can be used to bring the end portion of a single movable optical fiber into correspondence with the end portion of any one of two or more fixed optical fibers, and the resulting switch is termed a 1×2 optical switch or a 1×n optical switch.
However, the configuration of communication circuits is such that 2×2 optical switches are required. In a 2×2 optical switch, the end portions of two movable optical fibers oppose the end portions of two fixed optical fibers in such manner that the optical inputs can be mutually switched between the optical outputs. This can be implemented in practice using an optical branch circuit and two 1×2 optical switches, but an optical switching unit containing a large number of optical switches implemented in this way ends up being physically large and having a large optical loss due to the optical branch circuits.
A mechanical 2×2 optical switch designed to overcome this problem has been disclosed in JP 8-220456 A, which describes technology for implementing an optical path switch by providing a quadrilateral hole, arranging the end portions of fixed optical fibers at two corners of this hole, arranging the end portions of movable optical fibers at the other two corners of the hole, and employing electromagnetic means to change the position of the movable optical fibers.
Although the construction disclosed in the aforementioned patent publication, namely, arranging the end portions of optical fibers at respective corners of a quadrilateral opening, is excellent, it necessitates extremely high precision machining in order to realize an optical switch with little optical loss. Namely, to align the respective optical axes of the fixed optical fibers and the opposing movable optical fibers, it is necessary to produce a mirror finish on the inner walls of the opening. An optical switch with such a construction is unsuited to mass production and would therefore be expensive. Moreover, the fabrication step of producing a mirror finish has a poor yield, and this is another reason why such a component would be expensive. Furthermore, the optical switch itself has to be of sufficient size to enable such high precision surface machining to be performed, and hence a device utilizing a large number of such optical switches is inevitably of considerable size.
The present invention has been devised in the light of this situation. It is an object of this invention to provide a small 2×2 optical switch. It is a further object of this invention to provide a 2×2 optical switch that is well-suited to mass production. It is yet another object of the present invention to provide an optical switch that can be manufactured inexpensively and with high yield.
According to a well-known optical fiber switch construction, the end of an optical fiber is mounted on a movable member and the position of the optical fiber end is displaced mechanically by magnetic force. It is anticipated that this construction will provide a switch capable of stable operation with little signal attenuation. Moreover, this construction is similar in idea to an electromagnetic relay and will enable a reliable, stable product with uniform performance to be mass produced.
However, there is a limit as to how small a switching element with this construction can be made. That is to say, whereas many electronic components can now be fabricated in extremely small sizes, an optical switch is still relatively large.
The present invention has been devised in the light of this situation, and it is an object of the invention to further reduce the size of an optical switch of the type that switches optical paths by producing a mechanical displacement of optical fibers.
DISCLOSURE OF THE INVENTION
A distinguishing feature of the present invention according to a first aspect is a construction that facilitates inexpensive high-yield mass production of a 2×2 optical switch capable of mutually switching two optical communication paths comprising a pair of optical fibers.
Namely, the present invention is an optical switch comprising a pair of fixed optical fibers, a pair of movable optical fibers, a support member for supporting the end portions of these fixed optical fibers and movable optical fibers, and a drive mechanism mounted on this support member and producing a mechanical displacement of the end portions of the pair of movable optical fibers; wherein this drive mechanism includes means for producing displacement between a first position in which the optical axes of the end portions of the pair of movable optical fibers are respectively aligned with the optical axes of the end portions of the fixed optical fibers, and a second position in which the optical axes of the end portions of the pair of movable optical fibers are respectively aligned, in the reverse order to that of the first position, with the optical axes of the end portions of the fixed optical fibers. A distinguishing feature of this optical switch is that a pair of V-grooves are formed in the aforementioned support member, these V-grooves being arranged so that their opening portions are opposed and so that the end portions of the pair of fixed optical fibers are held in the respective bottom portions of the pair of grooves. A further distinguishing feature of this optical switch is that the aforementioned drive mechanism includes electromagnetic means for causing the end portions of the pair of movable optical fibers to come into contact with respective walls of this pair of V-grooves.
The support member can comprise two thin sheets stuck together, with a pair of beams formed on each such sheet. According to this construction, the pair of V-grooves appear at the face where the two thin sheets are stuck together, with the bottoms of the grooves lying within the plane at which the two sheets are stuck together. The pair of V-grooves thereby formed constitute part of an opening at the face where the two sheets are stuck together, and this opening has an hexagonal cross-section.
Preferably, the support member also includes means for holding the pair of movable optical fibers at a short distance from their ends, so that their end portions are cantilevered and their axes are positioned within a plane perpendicular to the plane containing the bottoms of the V-grooves. The aforementioned electromagnetic means preferably includes means for causing the ends of the pair of movable optical fibers to move in mutually different directions towards the walls of the V-grooves within a plane approximately perpendicular to the fiber axes, and means for causing the ends of the pair of movable optical fibers to
Hane Kazuhiro
Hara Keiichi
Kasajima Toshiyuki
Connelly-Cushwa Michelle R.
Mimaki Electronic Component Co., Ltd.
Pillsbury & Winthrop LLP
Ullah Akm E.
LandOfFree
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 Optical switch, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical switch will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2848842