Optical waveguides – With optical coupler – Switch
Reexamination Certificate
2002-03-11
2004-10-26
Ullah, Akm Enayet (Department: 2874)
Optical waveguides
With optical coupler
Switch
C385S017000
Reexamination Certificate
active
06810163
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an optical switch and an optical waveguide apparatus used for switching of optical connection in an optical communication system.
2. Description of the Background Art
Referring to
FIG. 26
, an optical switch is provided for an optical waveguide
105
of a film polymer
102
, i.e. a waveguide housing sheet
102
, held between holding plates
103
. Referring to
FIG. 27
, in an optical connection ON state (hereinafter simply referred to as ON state) in which a driving mechanism (push rod)
106
is not pushed at the crossing portion of the waveguide, waveguide housing sheet
102
keeps slit end surfaces
102
a
in contact with each other at a slit portion. Therefore, a core, i.e. waveguide
105
, is also held in contact at the slit portion. Hence, the light arrived at the contact slit portion passed through the slit portion without its direction changed.
On the other hand, in an optical connection OFF state (hereinafter simply referred to as OFF state) in which push rod
106
is being pushed, push rod
106
pushes open slit end surfaces
102
a
from one side and separates them, as shown in
FIG. 28
, to expose the slit end surfaces to the air. Thus, the light propagated in the waveguide with a high refractive index cannot exit from one of the slit end surfaces, and changes the travelling direction approximately 90° by total reflection due to the air in an air gap
109
, and then keeps being propagated.
According to the above system, in
FIG. 26
, when the optical connection at the crossing portion of the waveguide is in the ON state, light inputs L
1
, L
2
continuously pass through the portion where slit end surfaces
102
a
of a waveguide crossing portion
111
are in contact with each other. On the other hand, when the optical connection at the waveguide crossing portion is in the OFF state, input lights L
1
, L
2
both totally reflects at the portion of the optical switch and change the travelling directions approximately 90° to be output toward predetermined directions. As described above, the conventional optical switch is characterized in that the destination of light is switched by pushing/pulling one push rod
106
.
Such an optical switch as described above has a problem when it switches from the OFF state to the ON state. That is, when the switch is switched from the OFF state, i.e. the state in which the push rod is pushed to totally reflect the light, to the ON state, i.e. the state where the light passes through, pulling back of the push rod only provides resilient force from the elasticity of the film polymer. This has caused a problem such that the contact between slit end surfaces
102
a
of film polymer
102
is insufficient, and sufficient contact of core
105
cannot be obtained.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an optical switch and an optical waveguide apparatus with excellent reliability and durability, which can perform stable and reliable ON/OFF operation of optical connection at a crossing portion of the waveguide.
According to the first aspect of the present invention, an optical switch is provided in an optical waveguide apparatus including waveguides through which light is propagated and a waveguide housing sheet enclosing the waveguides. The optical switch includes a slit portion slitting to traverse the waveguides; a driver (a driving mechanism) performing an driving action onto the slit portion; and a driver assistant member located to interpose the slit portion between the driver and the driver assistant member to assist the driver. The driver and the driver assistant member push open the slit portion and provide a gap between the waveguides, and brings the slit portion into contact to connect the waveguides.
By such an arrangement, deformation for restoring the connection, which conventionally had a problem in reliability, can be performed using a driver and a driver assistant member, for example, by loose constraint from both sides of the slit portion. This means that two members interposing the slit portion may be used to perform ON/OFF operation from both sides, instead of the conventional case where only one driver was used to perform ON/OFF operation from one side. This ensures connection of the slit portion to be restored and allows reliable switching from OFF state to ON state. Deformation to push open the slit portion by the driver has conventionally been reliable. Therefore, by enhancing the reliability of the restoring connection of the slit portion, the reliability of ON/OFF operation of optical connection can be enhanced. It is noted that the driver assistant member may be a member moving toward/from the slit portion in a reciprocating manner by a driving signal. However, even in such a case, the driver assistant member does not move in the same manner as that of the driver, but rather, moves to assist the driver. Furthermore, the waveguide housing sheet may be constituted by a film polymer or the like. Here, the term ON/OFF described above does not mean only whether the optical switch shuts off or passes the light which is input into the waveguide crossing portion. For example, the term ON/OFF may rather be used to define switching of the optical connection (output destination).
In the optical switch according to the first aspect of the present invention, the slit portion is preferably slit from one side of the waveguide housing sheet without the slit reaching the other side of the waveguide housing sheet.
By leaving a non-separated portion at the slit portion, the non-separated portion can be a reference at the time of restoring the connection of the slit portion, enhancing the reliability of restoration in restoring the end surfaces of the cores, i.e. the waveguides, to bring them again into contact with each other. Therefore, the reliability of the switching from OFF state to ON state can be enhanced.
In the optical switch according to the first aspect of the present invention, waveguides cross with one another inside of the waveguide housing sheet, and the slit portion may be arranged diagonally traversing the crossing portion when viewed two-dimensionally.
The arrangement ensures the light propagated in the waveguides to select its traveling direction, as to whether it continuously travels across the crossing portion in the same direction or it changes the direction and travels along a crossing waveguide.
In the optical switch according to the first aspect of the present invention, the driver moves forward to or backward from the slit portion in accordance with a driving signal, and the driver assistant member cooperates with the movement of the driver to act on the slit portion. The driver and the driver assistant member can push open the slit portion and can restore the slit portion to be back in contact.
This allows the use of a simple driving mechanism, and thus the optical switch and the optical waveguide apparatus can be provided at a low cost.
The optical switch according to the first aspect, at least one of the driver and the driver assistant member may include a member movable forward and backward along a direction approximately perpendicular to the waveguide housing sheet.
This allows ON/OFF operation by a short-distance movement, increasing the response speed of the optical switch.
In the optical switch according to the first aspect, the waveguide housing sheet is held by holding plates so as to support the waveguide housing sheet. Each of the holding plates preferably has an opening at a position corresponding to the slit portion.
This can ensure flatness of the waveguide housing sheet and can prevent a loss due to deformation of the waveguide. As a result, an optical waveguide apparatus with low-loss can be realized.
The optical switch according to the first aspect, at least one of the driver and the driver assistant member can be constituted by a piezoelectric element mechanically deformed in accordance with a voltage application.
A normal voltage application can induce high stress of
Connelly-Cushwa Michelle R.
McDermott Will & Emery LLP
Mitsubishi Denki & Kabushiki Kaisha
Ullah Akm Enayet
LandOfFree
Optical switch and optical waveguide apparatus 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 and optical waveguide apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Optical switch and optical waveguide apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3322582