Optical waveguides – With optical coupler – Switch
Utility Patent
1999-05-07
2001-01-02
Phan, James (Department: 2872)
Optical waveguides
With optical coupler
Switch
C385S016000
Utility Patent
active
06169826
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to an optical switch by which an optical fiber is optically connected to another optical fiber selectively as required.
In a prior art optical switch disclosed in JP-A-6-208062, a magnetic member mounted on a movable optical fiber is magnetized by a coil surrounding the magnetic member to be urged toward either of permanent magnets arranged respective radial sides of the coil opposite to each other so that the movable optical fiber is displaced to be optically connected to either of stationary optical fibers selectively.
OBJECT AND SUMMARY OF THE INVENTION
An object of the present invention is to provide an optical switch for connecting optically a first optical fiber to a second optical fiber selectively as required, in which switch a switching operation is securely performed while a size of the optical switch is kept small.
In an optical switch for connecting optically at least one first optical fiber to at least one second optical fiber selectively, comprising, a stationary supporting block for supporting thereon a terminating end of the first optical fiber (the terminating end may project slightly from the stationary supporting block or may be completely surrounded by the stationary supporting block), a movable supporting block for supporting thereon a terminating end of the second optical fiber (the terminating end may project slightly from the movable supporting block or may be completely surrounded by the movable supporting block), being movable relative to the stationary supporting block between a first position for the optical connection between the terminating ends of the first and second optical fibers and a second position for disconnecting the optical connection therebetween, and being adjacent to the stationary supporting block, and a magnetic flux generator for generating a magnetic flux for moving the movable supporting block relative to the stationary supporting block.
According to the present invention, since the movable supporting block guided to be adjacent to the stationary supporting block includes a soft magnetic (feeble magnetism) substance so that the magnetic flux passes through the movable supporting block, the movable supporting block supporting thereon the terminating end of the second optical fiber is driven by the magnetic flux relative to the stationary supporting block adjacently or close to the stationary supporting block. Therefore, the terminating end of the second optical fiber is securely driven and correctly positioned relative to the terminating end of the first optical fiber, and the magnetic flux is effectively utilized to drive the movable supporting block so that a size of the magnetic flux generator, that is, a size of the optical switch is minimized.
If the soft magnetic substance of the movable supporting block is a soft magnetic ceramic (ceramic of feeble magnetism), a difference in expansion and contraction caused by temperature variation between the movable supporting block and the second optical fiber is made small while preventing a deterioration of a magnetic characteristic of the movable supporting block. If the stationary supporting block includes a ceramic having at least one of soft (feeble) magnetism and ferromagnetism, a difference in expansion and contraction caused by temperature variation between the stationary supporting block and the first optical fiber is made small while preventing a deterioration of a magnetic characteristic of the stationary supporting block. It is preferable for a thermal expansion coefficient of the stationary supporting block to be substantially equal to that of the movable supporting block, for maintaining a positional relationship between the first and second optical fibers correctly against the temperature variation of the optical switch. If the stationary supporting block includes at least one of a ceramic and a glass so that a difference in thermal expansion coefficient between the stationary supporting block and the first optical fiber is kept small, a thermal stress of at least one of the stationary supporting block and the first optical fiber is restrained. If the movable supporting block includes at least one of a ceramic and a glass so that a difference in thermal expansion coefficient between the movable supporting block and the second optical fiber is kept small, a thermal stress of at least one of the movable supporting block and the second optical fiber is restrained.
If a permanent magnet generates another magnetic flux sufficient for maintaining the movable supporting block at a selected or desired either one of the first and second positions when the magnetic flux generator is prevented from generating the magnetic flux, a so-called latching or self-hold of the optical switch when being deenergized is obtained. If the another magnetic flux passes through the stationary supporting block, the another magnetic flux effectively supplied to the movable supporting block. If the another magnetic flux passes through both of the stationary supporting block and the movable supporting block, the another magnetic flux effectively utilized for the latching or self-hold of the optical switch or the movable supporting block.
If the magnetic flux generated by the magnetic flux generator passes through both of the stationary supporting block and the movable supporting block, the magnetic flux effectively supplied to the movable supporting block. It is preferable for improving the effective supply of the magnetic flux to the movable supporting block that the stationary supporting block includes at least one of a soft magnetic (feeble magnetism) substance and a ferromagnetic or ferromagnetism substance so that the magnetic flux passes through the stationary supporting block. If the stationary supporting block and the movable supporting block includes a common soft magnetic (feeble magnetism) substance, differences in thermal deformation (expansion and contraction) and magnetic characteristic between the stationary supporting block and the movable supporting block is made small.
If the magnetic flux generator includes a first magnetic flux generator and a second magnetic flux generator, a direction of the magnetic flux (magnetic pole direction) generated by the first magnetic flux generator is opposite to a direction of the magnetic flux (magnetic pole direction) generated by the permanent magnet in a magnetic circuit including the movable supporting block (facing to or arranged between first and second front yoke (or core) portions of soft magnetism (feeble magnetism) opposite or facing to each other), the first magnetic flux generator, the first front yoke portion and the permanent magnet while a direction of the magnetic flux (magnetic pole direction) generated by the second magnetic flux generator is equal to the direction of the magnetic flux (magnetic pole direction) generated by the permanent magnet in a magnetic circuit including the movable supporting block, the second magnetic flux generator, the second front yoke portion and the permanent magnet, so that the movable supporting block moves from the first position to the second position by being drawn toward the second front yoke portion, and the direction of the magnetic flux (magnetic pole direction) generated by the first magnetic flux generator is equal to the direction of the magnetic flux (magnetic pole direction) generated by the permanent magnet in the magnetic circuit including the movable supporting block, the first magnetic flux generator, the first front yoke portion and the permanent magnet while the direction of the magnetic flux (magnetic pole direction) generated by the second magnetic flux generator is opposite to the direction of the magnetic flux (magnetic pole direction) generated by the permanent magnet in the magnetic circuit including the movable supporting block, the second magnetic flux generator, the second front yoke portion and the permanent magnet, so that the movable supporting block moves from the second position to the
Aida Yasuo
Horino Masaya
Mita Masahiro
Nakategawa Miki
Nishiyama Toshikazu
Finnegan Henderson Farabow Garrett & Dunner
Hitachi Metals Ltd.
Phan James
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