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Optical switch
| Details |
Inventors: Sakata, Tomomi; Togo, Hiroyoshi; Shimokawa, Fusao; Makihara, Mitsuhiro;
Assignee: Nippon Telegraph and Telephone Corporation (JP)
Primary Examiner: Kim; Ellen E.
Assistant Examiner:
Attorney, Agent or Firm: Venable, Frank; Robert J., Kaminski; Jeffri A.
An optical switch for switching a light path between two optical waveguides is provided. The switch has a slit formed diagonally cutting across the crossing point of crossing optical waveguides and a substance in the slit has a function of transmitting or reflecting an optical signal is selectively held in the slit. The slit is narrower than cores of the optical waveguides, and has a center line formed on a bisection of an interior angle between optical axes of the crossing optical waveguides. Thus, the substance in the slit serves to make optical intensity reflected to each of the optical waveguides uniform. Further, a crossing optical waveguide consists of a reflecting structure having its interior filled with air during reflection and the intersecting angle between the first group of optical waveguides is between 0 to 90 degrees and preferably substantially between 73 and 74 degrees. |
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DETAILED DESCRIPTION To attain the above first object, in an optical switch according to a first aspect of the present invention, a center line of a slit having two opposed side walls (physical reflection planes) is aligned with a bisector (ideal reflection plane) of an interior angle at a crossing point of optical-axis center lines of crossing optical waveguides, and a Goos-Hanchen shift effect on a light reflection plane (optical reflection plane) caused by light soaking is positively used to reduce an amount of positional deviation of the optical reflection plane from the ideal reflection plane.
Thus, this optical switch utilizes both opposed side walls of the slit fabricated at the crossing point of optical waveguides crossing each other in an optical waveguide layer as the physical reflection plane that freely switches a light path of the crossing optical waveguides by actively utilizing the Goos-Hanchen shift effect.
The optical switch can reduce the positional deviation of the reflection plane, and thereby simultaneously can switch the light paths in the crossing optical waveguides with a low loss.
In addition, since the slit of the optical switch is located at the center of the crossing point of the crossing optical waveguides, and the optical switch uses both side walls of the slit as reflecting wall surfaces of the same characteristics, lights reflected by these side walls of the slit have an equal intensity.
Therefore, according to the first aspect of the present invention, this optical switch can provide a 2.
times.
2 optical switch function through a single element without the needs for any amplifier or attenuator for equalizing the light intensity.
Accordingly, the size of the 2.
times.
2 optical switch, which conventionally requires three or more optical switches, can be reduced to a third part or less, thereby enabling this optical switch to be implemented at a low price.
Further, an optical switch providing the 2.
times.
2 switch function can be constructed using optical switch elements with a third part of elements that is required for the conventional optical switch
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Optical Systems 
