Pirelli Cavi S.p.a.

Pirelli Cavi E Sistemi S.p.a.

Corning O.t.i. Spa

Steffen Schmid

Salvatore Morasca

Sergio Bosso

Paolo Ottolenghi

Filippo Bentivoglio Ravasio

Massimo Frascolla

Stefano Donati

Harald Herrmann

An apparatus and method for reducing polarization hole burning in a rare-earth-doped fiber amplifier within an optical communication system by converting an optical carrier having a characteristic wavelength into a polarization-rotating optical carrier is disclosed. The apparatus includes a polarization-fixing device optically coupled in the optical transmission system to transform the optical carrier to a polarized optical carrier, and an acousto-optic modulator positioned to receive a first portion of the polarized optical carrier and to orthogonally convert the polarization of the polarized optical carrier and to shift the polarized optical carrier by a modulation frequency. The apparatus and method further includes a polarization beam combiner optically coupled to receive the orthogonally polarization converted and frequency shifted polarized signal and a portion of the original polarized optical carrier. The polarization beam combiner produces a polarization-rotating carrier signal that is transmitted downstream in the optical communication system to a rare-earth-doped fiber amplifier.

Suppression of polarization hole burning with an acousto-optic modulator

A double-passage acousto-optical device including an acousto-optical switch having a first polarization conversion region connected between first input and output ports, and a second conversion region connected between second input and output ports; and an optical combination connected between the first output port and the second input port via optical fibers and including an optical isolating element. The double-passage acousto-optical device may alternately include an acousto-optical switch including a single polarization conversion region connected between first input and output ports and also connected between second input and output ports. A bandpass filter, a notch filter, and add/drop and a tunable laser generator may be formed using the acousto-optical device.

Double-passage acousto-optical device and laser

The invention relates to optical birefringent waveguides, acousto-optical devices using such optical waveguides and an acoustic waveguide as well as a manufacturing method therefore. The optical waveguides of the invention exhibit a small birefringent variation with respect to a change of waveguide parameters, if the fundamental mode propagating in the optical waveguide has a propagation constant near to the cut-off condition. The optical waveguide dimensions are typically chosen such that the cut-off wavelength of the waveguide is below 1650 nm for an operating wavelength in the window between 1530 nm and 1656 nm. The acousto-optic mode converter using such optical waveguides have a superior conversion characteristic over the conversion frequency with reduced side lobes. Therefore, using the thin and narrow optical waveguides of the invention, a superior performance of the acousto-optical devices using such an optical waveguide can be obtained.

Waveguide structures in particular for use in acousto-optical mode converters and method for making same

An acousto-optical waveguide device with compensation of polarization mode dispersion (PMD) comprises at least one first and one second optical path in optical waveguide and at least one compensation optical path connected to the first and second optical path. The compensation optical path has a prefixed PMD such that the passage time of a first polarization component of an optical signal in the first optical path and in the compensation optical path is substantially equal to the passage time of a second polarization component in the second optical path and in the compensation optical path.

Acousto-optical waveguide device with compensation of polarization mode

A double-stage acousto-optical waveguide device comprises two polarization conversion stages, a polarization selective input element, a polarization selective output element and two intermediate polarization selective elements that have two branches connected together and two branches not connected together that are located on opposite sides of the branches connected together and extend in lateral waveguides that reach the edges of the substrate.

Double-stage acousto-optical waveguide device, having

An acoustooptical wavelength device for wavelength selection includes one substrate of a birefringent and photoelastic material on which there is formed: first and second rotation stages of the polarization plane of an optical signal in a first wavelength interval, wherein each stage comprises at least one optical waveguide traveled over by the signal; at least one optical waveguide, connecting the two stages and carrying one single polarizer consisting of an evanescent-wave polarization coupler; and at least one optical waveguide carrying one polarizer being finally provided downstream of the second stage.

Acoustooptical waveguide device for wavelength selection and process for

A wavelength selective acousto-optical waveguide device comprises a first and a second optical path in an optical waveguide having a length different by an amount corresponding to a value d=.+-..lambda.(k +m) where d is the difference between the optical paths of the two waveguides, .lambda. is the wavelength of the optical signal, k is a number greater than 0 and less than 1; and m is 0 or a whole number, so as to create a phase shift between at least two parasitic components of the optical signal, such as to generate a destructive interference between the parasitic components.

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Monza, Italy

Steffen Schmid