US 6,285,810 B1 · Tunable add/drop optical device

Abstract

Tunable add/drop optical device for injecting or extracting (add/drop) at least a selected optical channel or carrier wavelength in or from a set of multiplexed channels or carriers of different wavelengths comprising a plurality of directional couplers (AD1 . . . AD6) and a plurality of phase-shift stages (SF1 . . . SF5) alternately connected in cascade, wherein each phase-shift stage defines a certain optical path length difference (ΔL1 . . . ΔL5) between two distinct optical paths of the stage. The tuning is performed modifying the refraction index of one path of said phase shift stages by means of Joule effect heating strips (L1 . . . L5) or by means of metallic field plates adapted to receive a signal suitable to modify the electric field intensity. The first two phase-shift stages of said plurality of phase-shift stages have differences of length of optical paths different from each other and in a preestablished ratio while the remaining phase-shift stages have differences of length of optical paths identical. It is thus possible to provide a device having an exceptionally flat cross response characteristic, substantially free of ripple due to an inevitable truncation of the Fourier expansion series.

Claims20

Dependent claims

Tunable add/drop optical device adapted to handle wavelength division multiplexed (WDM) signals, for injecting or extracting (add/drop) at least a selected optical channel or carrier wavelength in or from a set of multiplexed channels or carriers of different wavelength, comprising a plurality of directional couplers and a plurality of phase-shift stages, alternately connected in cascade, wherein each phase-shift stage defines a certain optical path length difference between two distinct optical paths of the stage, causing a periodic response characteristic with a spectral separation between two adjacent peaks of said periodic response characteristic sufficient to contain all deselected wavelengths of said multiplexed channels when a peak of the periodic response characteristic is centered on a selected wavelength, characterized in that

the optical medium constituting one of said two distinct optical paths of each of said phase-shift stages has a refraction index dependent from a physical parameter belonging to the group composed of temperature and electric field intensity and the device includes bias means for controllably varying said parameter.

A tunable add/drop optical device adapted to handle wavelength division multiplexed (WDM) signals, for injecting or extracting (add/drop) at least a selected optical channel or carrier wavelength from a set of multiplexed channels or carriers of different wavelength, said optical device comprising:

a biasing circuit controllably varying a physical parameter;
plural directional couplers;
and
plural phase-shift stages alternately connected in cascade to said plural directional couplers,
wherein each said at least one phase-shift stage has at least two distinct optical paths having a certain optical path length difference therebetween, said certain optical path length causing a periodic response characteristic with a spectral separation between adjacent peaks containing all deselected wavelengths of said multiplexed channels when a peak of the periodic response characteristic is centered on a selected wavelength, wherein the optical medium constituting one of said at least two distinct optical paths of each of said phase-shift stages has a refraction index varying in dependence on said physical parameter, and wherein said plural directional couplers and said plural phase-shift stages from at least one optical arrangement.

2 more elements

Dependencies are inferred from the claim text.

Tunable add/drop optical device

Life of this patent

Tunable add/drop optical device

Life of this patent

Abstract

Claims20