Compact mach-zehnder interferometer and wavelength reference employing same
First Claim
1. In a Mach-Zehnder optical interferometer comprising a pair of optical waveguides extending between a pair of optical coupling regions, said waveguides having different optical paths between said coupling regions for producing transmission maxima and minima,the improvement wherein each waveguide of said pair comprises a first segment, a second segment and a reflector optically coupling said first segment and said second segment.
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Abstract
The present invention includes a MZI comprising a pair of folded waveguides disposed between a pair of couplers. Each folded waveguide comprises a pair of segments intersecting at a reflector. The respective reflectors are different distances from the couplers to provide a major portion of the differential path length between the two arms. In a preferred embodiment, the reflectors are polysilicon mirrors and can be formed by etching through the intersecting waveguides and depositing polysilicon. The result is a compact MZI that can be used as a multiwavelength reference for a laser light source on a common silicon optical bench chip.
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Citations
9 Claims
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1. In a Mach-Zehnder optical interferometer comprising a pair of optical waveguides extending between a pair of optical coupling regions, said waveguides having different optical paths between said coupling regions for producing transmission maxima and minima,
the improvement wherein each waveguide of said pair comprises a first segment, a second segment and a reflector optically coupling said first segment and said second segment.
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4. In an optical interferometer comprising a pair of optical waveguides extending between a pair of optical coupling regions, said waveguides having different optical paths between said coupling regions for producing transmission maxima and minima,
the improvement wherein each waveguide of said pair comprises a first segment, a second segment and a reflector optically coupling the first segment and the second segment wherein each said reflector comprises polysilicon.
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5. In an optical reference source comprising an electrically controllable optical source, an optical interferometer optically coupled to said optical source, a photodiode for producing an electrical signal indicative of the output of said interferometer, and a feedback circuit for controlling said optical source in accordance with said electrical signal,
the improvement wherein said optical interferometer comprises a pair of optical waveguides extending between a pair of optical coupling regions, said waveguides having different optical paths between said coupling regions for producing transmission maxima and minima, and each waveguide of said pair comprises a first segment, a second segment and a reflector optically coupling the first segment and the second segment.
Specification