Y branching optical waveguide and optical integrated circuit
First Claim
1. A Y branch optical waveguide, comprising:
- a first optical waveguide;
two second optical waveguides; and
a multi-mode optical waveguide connected between said first optical waveguide and said two second optical waveguides;
wherein the width of said first optical waveguide and the width of said multi-mode optical waveguide are different in a direction orthogonal to an extension of an optical axis at a portion where said first optical waveguide and said multi-mode optical waveguide are connected to each other, and said multi-mode optical waveguide has shapes asymmetric with respect to an extension of a center line, extending in the direction of the optical axis, of said first optical waveguide so that propagation light has an asymmetric optical intensity distribution at a portion where said multi-mode optical waveguide and second optical waveguides are connected when light is incident from said first optical waveguide, and said optical intensity distribution has a first peak and a second peak different in light intensity from each other and each of said peaks is located at near a center of each of said second optical waveguides at portions where said multi-mode optical waveguide and said second optical waveguides are connected, respectively.
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Accused Products
Abstract
The present application provides an asymmetric Y branch optical waveguide capable of obtaining an asymmetric branching ratio stably with a low radiation loss, and a lightwave circuit and an optical transmission system both using the asymmetric Y branch optical waveguide. The asymmetric Y branch optical waveguide according to the present application has a waveguide (I) for input, two waveguides (III) for output, and a multi-mode waveguide (II) disposed between the waveguides (I) and (II). The present Y branch optical waveguide is constructed in such a manner that the width of the multi-mode waveguide, extending in the direction intersecting with an optical axis changes discontinuously at a portion where the input waveguide and the multi-mode waveguide are connected to each other, and the multi-mode waveguide is asymmetric with respect to a center line extending in the direction of the optical axis to allow optical peaks to respectively appear in each individuals of the two output waveguides. Thus, a difference occurs between peak'"'"'s heights in each light-intensity distribution having two peaks, which appears due to mode interference, so that the asymmetry of a branching ratio can be implemented.
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Citations
23 Claims
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1. A Y branch optical waveguide, comprising:
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a first optical waveguide;
two second optical waveguides; and
a multi-mode optical waveguide connected between said first optical waveguide and said two second optical waveguides;
whereinthe width of said first optical waveguide and the width of said multi-mode optical waveguide are different in a direction orthogonal to an extension of an optical axis at a portion where said first optical waveguide and said multi-mode optical waveguide are connected to each other, and said multi-mode optical waveguide has shapes asymmetric with respect to an extension of a center line, extending in the direction of the optical axis, of said first optical waveguide so that propagation light has an asymmetric optical intensity distribution at a portion where said multi-mode optical waveguide and second optical waveguides are connected when light is incident from said first optical waveguide, and said optical intensity distribution has a first peak and a second peak different in light intensity from each other and each of said peaks is located at near a center of each of said second optical waveguides at portions where said multi-mode optical waveguide and said second optical waveguides are connected, respectively. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A Y branch optical waveguide, comprising:
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a first optical waveguide;
two second optical waveguides; and
a multi-mode optical waveguide connected between said first optical waveguide and said two second optical waveguides;
whereinthe width of said first optical waveguide extending in the direction orthogonal to an extension of an optical axis has discontinuity at a portion where said first optical waveguide and said multi-mode optical waveguide are connected to each other, and said multi-mode optical waveguide has shapes asymmetric with respect to an extension of a center line, extending in the direction of the optical axis of said first optical waveguide so that propagation light has a first peak and a second peak different in light intensity from each other in association with each of said two second optical waveguides when the light is incident from said first optical waveguide, and the distance between one side of the core portion of said multi-mode optical waveguide and the extension of the center line, extending in the direction of the optical axis, of said first optical waveguide is formed so as to increase in sine function form from the entrance to its corresponding exit.
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22. The Y branch optical waveguide comprising:
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a first optical waveguide;
two second optical waveguides; and
a multi-mode optical waveguide connected between said first optical waveguide and said two second optical waveguides;
whereinthe width of said first optical waveguide, extending in the direction orthogonal to an extension of an optical axis has discontinuity at a portion where said first optical waveguide and said multi-mode optical waveguide are connected to each other, and said multi-mode optical waveguide has shapes asymmetric with respect to an extension of a center line, extending in the direction of the optical axis, of said first optical waveguide so that propagation light has a first peak and a second peak different in light intensity from each other in association with each of said two second optical waveguides when the light is incident from said first optical waveguide, and the distance between one side of the core portion of said multi-mode optical waveguide and the extension of the center line, extending in the direction of the optical axis, of said first optical waveguide is formed so as to increase in Raised Sin form from the entrance to its corresponding exit.
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23. A Y branch optical waveguide, comprising:
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a first optical waveguide;
two second optical waveguides; and
a multi-mode optical waveguide disposed between said first optical waveguide and said two second optical waveguides;
wherein in the width of said first optical waveguide and the width of said multi-mode optical waveguide are different in the direction orthogonal to an extension of an optical axis at a portion where said first optical waveguide and said multi-mode optical waveguide are connected to each other, and said multi-mode optical waveguide has shapes formed asymmetrically with respect to the extension of the center line, extending in the direction of the optical axis, of said first optical waveguide so that distributions of light intensities at a surface intersecting an optical axis of propagation light perpendicular thereto have two maximum values different in light intensity from each other when the light is incident from said first optical waveguide and each of said two maximum values of light intensity are located at near a center of each of said second optical waveguides at portions where said multi-mode optical waveguide and said second optical waveguides are connected, respectively.
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Specification