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US 8,478,083 B2Granted
Multi-stage polarization rotator
AssigneeInfinera Corporation
InventorBrent E. Little
Life of this patent
Estimating the term…
Abstract
Consistent with the present disclosure, a rotator is provided that includes multiple stages, each of which including waveplate and delay sections. The waveplate and delay sections each exhibit birefringence and have polarization eigen states that are tilted with respect to each other. The lengths of the delay and waveplate sections are selected such that, for example, a relatively high extinction ratio can be achieved over a relatively wide range of fabrication perturbations to the waveplates or delay sections and over a relatively wide range of wavelengths. Accordingly, the rotator consistent with the present disclosure is more tolerant of deviations in the optical signal polarization.
Claims21
An apparatus, comprising:
- a substrate;
- an input waveguide provided on the substrate, the input waveguide receiving an optical signal, the optical signal having a first polarization in the input waveguide;
- a first waveplate waveguide provided on the substrate, the first waveplate waveguide receiving the optical signal, the first waveplate waveguide having first and second waveplate eigen modes, which are oriented along first and second directions, respectively;
- a delay waveguide provided on the substrate, the first waveplate waveguide supplying the optical signal to the first delay waveguide, the delay waveguide having first and second delay eigen modes, which are oriented along third and fourth directions, respectively;
- a second waveplate waveguide provided on the substrate, the second waveplate waveguide receiving the optical signal from the first delay waveguide, the second waveplate waveguide having the first and second waveplate eigen modes;
- and
- an output waveguide provided on the substrate, the output waveguide supplying the optical signal, such that the optical signal in the output waveguide has a second polarization different than the first polarization
- wherein the delay waveguide is one of a plurality of delay waveguides provided along an optical path in which the optical signal propagates from the input waveguide to the output waveguide.
5 more elements
An apparatus, comprising:
- a substrate;
- an input waveguide provided on the substrate, the input waveguide receiving an optical signal, the optical signal having a first polarization in the input waveguide;
- a first waveplate waveguide provided on the substrate, the first waveplate waveguide receiving the optical signal, the first waveplate waveguide having first and second waveplate eigen modes, which are oriented along first and second directions, respectively;
- a delay waveguide provided on the substrate, the first waveplate waveguide supplying the optical signal to the delay waveguide, the delay waveguide having first and second delay eigen modes, which are oriented along third and fourth directions, respectively;
- a second waveplate waveguide provided on the substrate, the second waveplate waveguide receiving the optical signal from the delay waveguide, the second waveplate waveguide having the first and second waveplate eigen modes;
- and
- an output waveguide provided on the substrate, the output waveguide supplying the optical signal, such that the optical signal in the output waveguide has a second polarization different than the first polarization,
- wherein each of the first and second waveplate waveguides is curved, such that a first mode index associated with the first eigen mode is different than a second mode index associated with the second eigen mode.
5 more elements
An apparatus comprising:
- a substrate;
- an input waveguide provided on the substrate, the input waveguide receiving an optical signal, the optical signal having a first polarization in the input waveguide;
- a first waveplate waveguide provided on the substrate, the first waveplate waveguide receiving the optical signal, the first waveplate waveguide having first and second waveplate eigen modes, which are oriented along first and second directions, respectively;
- a delay waveguide provided on the substrate, the first waveplate waveguide supplying the optical signal to the delay waveguide, the delay waveguide having first and second delay eigen modes, which are oriented along third and fourth directions, respectively;
- a second waveplate waveguide provided on the substrate, the second waveplate waveguide receiving the optical signal from the delay waveguide, the second waveplate waveguide having the first and second waveplate eigen modes;
- and
- an output waveguide provided on the substrate, the output waveguide supplying the optical signal, such that the optical signal in the output waveguide has a second polarization different than the first polarization,
- wherein an angle between one of the first and second directions and one of the third and fourth directions is substantially equal to 45 degrees.
5 more elements
An apparatus, comprising:
- a first waveplate slab receiving an optical signal, the first waveplate slab having first and second waveplate eigen modes, which are oriented along first and second directions, respectively;
- a delay slab, the first waveplate slab supplying the optical signal to the first delay slab, the delay slab having first and second delay eigen modes, which are oriented along third and fourth directions, respectively;
- a second waveplate slab receiving the optical signal from the first delay slab, the second waveplate slab having the first and second waveplate eigen modes,
- wherein the second waveplate slab supplies the optical signal with a second polarization different than the first polarization, and the delay slab is one of a plurality of delay slabs provided along an optical path in which the optical signal propagates from the first waveplate slab to the second waveplate slab.
1 more element
Dependencies are inferred from the claim text.