Super-Steep Step-Phase Interferometer
OwnerYung-Chieh Hsiehinventor
Life of this patent
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Abstract
Step-phase interferometers are provided for use as optical interleavers/de-interleaver for optical communication. High data rates require a wide band-width to pass the high-speed modulated optical spectrum, and further require a wide stop-band to reject the signal from adjacent channels. The present interferometers provide a steep slope at the transition from the passband to the adjacent stop-band, thereby enlarging the width of both the pass-band and stop-band.
Claims31
A step-phase interferometer, comprising:
- an interferometer first arm comprising a linear phase offset spacer and a first resonant cavity, wherein said first resonant cavity is formed by a first partially reflective surface and a first mirror;
- an interferometer second arm comprising a second resonant cavity having a second partially reflective surface and a second mirror, wherein the optical path length of said first resonant cavity and the optical path length of said second resonant cavity are about equal;
- and
- a beamsplitter having a splitting location configured to split an input beam of light into a first beam and a second beam, wherein said beamsplitter is configured to direct said first beam into said first arm, wherein said first beam will propagate first through said linear phase offset spacer and will then be reflected by said first resonant cavity to produce a first reflected beam that will then return to said beamsplitter, wherein said beamsplitter is configured to direct said second beam into said second arm, where in said second beam will be reflected by said second resonant cavity to produce a second reflected beam that will then return to said beamsplitter and combine with said first beam;
- wherein the optical path difference from said splitting location to said first partially reflective surface and said second partially reflective surface is about halt the optical path length of said first resonant cavity and wherein the frequency dependence of the phase difference between said first reflected been and said second reflected beam has a step-like function.
The step-phase interferometer of claim wherein said linear phase offset spacer comprises an AR coated surface offset with a first athermal spacer from a second AR coated surface, wherein said first partially reflective surface is offset with a second athermal spacer from said first minor and wherein said second partially reflective surface is offset with a third athermal spacer from said second mirror.
An optical step-phase interferometer, comprising:
- a beamsplitter to separate an incident beam of light into a first beam of light and a second beam of light;
- a linear phase offset spacer operatively positioned within the path of said first beam of light;
- a first non-linear phase generator (NLPG) operatively positioned to reflect said first beam of light, after said first beam of light passes through said linear phase offset spacer, to produce a first reflected beam;
- a second non-linear phase generator (NLPG) operatively positioned to reflect said second beam of light to produce a second reflected beam,
- wherein said first reflected beam and said second reflected beam interfere with one another, wherein the frequency dependence of the phase difference between said first reflected beam and said second reflected beam has a step-like function.
A method of interleaving frequencies of light, comprising:
- separating, with a beamsplitter, an incident beam of light into a first beam of light and a second beam of light;
- passing, said first beam of light through a linear phase offset spacer,
- reflecting said first beam of light with a first non-linear phase generator (NLPG), after said first beam of light passes through said linear phase offset spacer, to produce a first reflected beam:
- reflecting said second beam of light with a second non-linear phase generator (NLPG) to produce a second reflected beam,
- wherein said first reflected beam and said second reflected beam interfere with one another, wherein the frequency dependence of the phase difference between said first reflected beam and said second reflected beam has a step-like function.
Dependencies are inferred from the claim text.