Abstract: An optical device includes an optical splitter having an input port, a first output port and a second output port and is adapted to receive at said input port a WDM optical signal including a plurality of channels equally spaced by a frequency spacing and occupying an optical bandwidth, and wherein the optical splitter is adapted to output at the first and second output ports, respectively, a first and a second portion of the optical signal; an optical combiner having a respective first and second input ports and a respective output port; a first optical path optically connecting the first output port of the optical splitter to the first input port of the optical combiner; a second optical path optically connecting the second output port of the optical splitter to the second input port of the optical combiner, a first optical filter optically coupled along the first optical path, and a second optical filter optically coupled to the second optical path and the free spectral range of both the first and the seco

Abstract: The method for filtering an optical signal comprising a plurality of channels lying on a grid of optical frequencies equally spaced by a frequency spacing and occupying an optical bandwidth, comprises: a) operating an optical filter comprising a plurality of resonators, wherein a first resonator of the plurality is optically coupled to the optical signal and the remaining resonators are optically coupled in series to the first resonator, so that a respective resonance of each one of the plurality of resonators falls within a first frequency band having bandwidth less than or equal to 15 GHz; b) operating the optical filter so as to obtain a separation between said respective resonance of at least one resonator with respect to said respective resonance of at least another different resonator, the separation being greater than or equal to 25 GHz; c) operating the optical filter so that said respective resonance of each one of the plurality of resonators falls within a second frequency band, different from the f

Abstract: A method of filtering an optical signal includes operating an optical filter having resonators, each having a respective free spectral range and a respective resonance falling within a first frequency band, first tuning at least one resonator with respect to at least another resonator to obtain a separation between any resonance of at least one resonator falling within an optical bandwidth with respect to a resonance of at least another resonator nearest to the any resonance, second tuning all the resonators of the optical filter so as to move all respective resonances by a respective frequency interval greater than a frequency spacing, and third tuning the at least one resonator and the at least another resonator such that a further respective resonance of each one of the resonators falls within a second frequency band, different from the first frequency band.

Abstract: An optical mode transformer comprises a first waveguide including a first core, a first cladding and an end facet configured to be coupled to an optical fiber. A second waveguide comprises a second core and a second cladding, and is arranged with respect to the first waveguide so as to realize an evanescent optical coupling with the first waveguide. The second core comprises a tapered region, in at least a portion of which the evanescent coupling takes place. The first core and the second core are separated by a gap. A first refractive index contrast of the first waveguide is less than a second refractive index contrast of the second waveguide.

Abstract: An optical mode transformer comprises a first waveguide including a first core, a first cladding and an end facet configured to be coupled to an optical fiber. The transformer further includes a second waveguide comprising a second core, a second cladding and an end directly coupled to an end of the first waveguide. A third waveguide comprises a third core and a third cladding, and is arranged with respect to the second waveguide so as to realize an evanescent optical coupling with the second waveguide. The third core includes a tapered region wherein evanescent coupling takes place, and wherein a refractive index contrast of the first waveguide is less than a refractive index contrast of the second waveguide, the refractive index contrast of the second waveguide is less than a refractive index contrast of the third waveguide, and the refractive index contrast of the third waveguide is not less than 18%.

Abstract: An optical device includes an optical splitter having a resonant structure including at least a resonator, the optical splitter being adapted to receive at an input port a WDM optical signal and to output at first and second output ports, respectively, a first and a second portion of the optical signal, the second portion including the channels spaced by an integer multiple of the WDM frequency spacing; an optical combiner adapted to receive at first and second input ports, respectively, the first and the second portions and adapted to output them at an output port; a first optical path optically connecting the first output port to the first input port; a second optical path optically connecting the second output port to the second input port; and an optical filter optically coupled to the second optical path, wherein the optical combiner includes at least a resonator.

Abstract: An optical modulator has an optical splitter for splitting an input light beam into a first and second light beam; a first and a second wave-guide arm connected to the optical splitter for receiving and transmitting therethrough the first and second light beam, respectively, the waveguide arms each including a core region having group IV semiconductor material or a combination of group IV semiconductor materials; an optical combiner connected to the first and second waveguide arm for receiving the first and second light beam and combining them into an output light beam; a first and a second electrode structure associated with the first and second waveguide arm, respectively; and a driving circuit for supplying voltage to the first and second electrode structure. The driving circuit is adapted to supply a first modulation voltage super-imposed to a first bias voltage to the first electrode structure and a second modulation voltage superimposed to a second bias voltage to the second electrode structure.

Abstract: An optical device includes an optical splitter having an input port, a first output port, a second output port and a resonant structure including at least a resonator, the optical splitter being adapted to receive at the input port a WDM optical signal and to output at the first and second output ports, respectively, a first and a second portion of the optical signal, the second portion including the channels lying on a sub-grid of optical frequencies spaced by an integer multiple of the WDM frequency spacing; an optical combiner having a first input port, a second input port, an output port and adapted to receive at the first and second input ports, respectively, the first and the second portions and adapted to output them at said output port; a first optical path optically connecting the first output port of the optical splitter to the first input port of the optical combiner so as to propagate the first portion; a second optical path optically connecting the second output port of the optical splitter to th

Abstract: A method for switching from a first optical path optically coupled to an optical processing device to a second optical path, the first and second optical paths optically connecting, in parallel configuration, a first optical switch to a second optical switch, according to the following steps: directing optical radiation comprising at least a fast operating wavelength through the first optical path to the optical processing device, which is tuned to the first operating wavelength; tuning a resonant all-pass filter optically coupled to the second optical path so as to match, at least at a wavelength adjacent to the first operating wavelength, a phase distortion introduced by the optical processing device on the optical radiation; synchronously actuating the first and the second optical switch so as to switch the optical radiation from the first optical path to the second optical path.

Abstract: An optical mode transformer comprises a first waveguide including a first core, a first cladding and an end facet configured to be coupled to an optical fiber. The transformer further includes a second waveguide comprising a second core, a second cladding and an end directly coupled to an end of the first waveguide. A third waveguide comprises a third core and a third cladding, and is arranged with respect to the second waveguide so as to realize an evanescent optical coupling with the second waveguide. The third core includes a tapered region wherein evanescent coupling takes place, and wherein a refractive index contrast of the first waveguide is less than a refractive index contrast of the second waveguide, the refractive index contrast of the second waveguide is less than a refractive index contrast of the third waveguide, and the refractive index contrast of the third waveguide is not less than 18%.

Abstract: A semiconductor-based optical mode transformer (100, 100?, 100?) is described for coupling an optical mode of an optical fiber (3) with an optical mode of a waveguide (2a). The optical mode transformer comprises a first waveguide (1a) extending along a first main longitudinal direction (Z) and including an end facet (9) being apt to be coupled to the optical fiber (3), said first waveguide (1a) including a first core (1) and a first cladding (6,4) and having a first refractive index contrast (?n1); and a second waveguide (2a) arranged with respect to said first waveguide so as to realize an evanescent optical coupling with said first waveguide (1a), the second waveguide (2a) comprising a second core (2) and a second cladding (4,7) and having a second refractive index contrast (?n2). In addition, the second core (2) comprises a tapered region (13,13?), in at least a portion of which said evanescent coupling takes place.

Abstract: The method for filtering an optical signal comprising a plurality of channels lying on a grid of optical frequencies equally spaced by a frequency spacing and occupying an optical bandwidth, comprises: a) operating an optical filter comprising a plurality of resonators, wherein a first resonator of the plurality is optically coupled to the optical signal and the remaining resonators are optically coupled in series to the first resonator, so that a respective resonance of each one of the plurality of resonators falls within a first frequency band having bandwidth less than or equal to 15 GHz; b) operating the optical filter so as to obtain a separation between said respective resonance of at least one resonator with respect to said respective resonance of at least another different resonator, the separation being greater than or equal to 25 GHz; c) operating the optical filter so that said respective resonance of each one of the plurality of resonators falls within a second frequency band, different from the f

Abstract: The method for filtering an optical signal comprising a plurality of channels lying on a grid of optical frequencies equally spaced by a given frequency spacing and occupying an optical bandwidth, comprises: a) splitting the optical signal into a first and a second portion spatially separated, wherein the first portion comprises the channels which lie on a first sub-grid comprising a first set of the optical frequencies equally spaced by the double of the frequency spacing and the second portion substantially comprises the remaining channels; b) operating a first optical filter comprising a plurality of resonators, wherein a first resonator of the plurality is optically coupled to the first portion and the remaining resonators are optically coupled in series to the first resonator, so that a respective resonance of each one of the plurality of resonators falls within a first frequency band having bandwidth less than or equal to 15 GHz and comprising a first channel belonging to the first portion; c) operating

Abstract: The method for filtering an optical signal comprising a plurality of channels lying on a grid of optical frequencies equally spaced by a frequency spacing and occupying an optical bandwidth, comprises: a) operating an optical filter comprising a plurality of resonators each having a respective free spectral range, wherein a first resonator of the plurality is optically coupled to the optical signal and the remaining resonators are optically coupled in series to the first resonator, so that a respective resonance of each one of the plurality of resonators falls within a first frequency band having bandwidth less than or equal to 15 GHz; b) operating the optical filter so as to obtain a separation between any resonance of at least one resonator falling within the optical bandwidth with respect to a resonance of at least another different resonator nearest to the any resonance, the separation being greater than or equal to 150 GHz and no more than 1 THz; c) tuning all the resonators of the optical filter so as t

Abstract: An optical device includes an optical splitter having an input port, a first output port and a second output port and is adapted to receive at said input port a WDM optical signal including a plurality of channels equally spaced by a frequency spacing and occupying an optical bandwidth, and wherein the optical splitter is adapted to output at the first and second output ports, respectively, a first and a second portion of the optical signal; an optical combiner having a respective first and second input ports and a respective output port; a first optical path optically connecting the first output port of the optical splitter to the first input port of the optical combiner; a second optical path optically connecting the second output port of the optical splitter to the second input port of the optical combiner, a first optical filter optically coupled along the first optical path, and a second optical filter optically coupled to the second optical path and the free spectral range of both the first and the seco

Abstract: An optical device, i.e., a wavelength selective filter, includes a grating having a finite length and is capable of filtering a given first wavelength within an operating wavelength region, said grating including a plurality of consecutive sections, each section including two sub-sections: a first sub-section having a first period ? and a second sub-section having a second period ?1, wherein said first period (?) satisfies the Bragg condition for said given first wavelength and the second period (?1) satisfies the Bragg condition for a second wavelength lying outside the operating wavelength region so as to form a grating with modulated coupling coefficient, wherein the succession of lengths of each section is non periodic. Preferably, the first (?) and second period (?1) are such that n?=m?1, wherein n and m are integers and satisfy one of the following conditions: if ?1>?, n/m is not an integer and if ?1<?, m/n is not an integer.

Abstract: An optical device includes an optical splitter having an input port, a first output port, a second output port and a resonant structure including at least a resonator, the optical splitter being adapted to receive at the input port a WDM optical signal and to output at the first and second output ports, respectively, a first and a second portion of the optical signal, the second portion including the channels lying on a sub-grid of optical frequencies spaced by an integer multiple of the WDM frequency spacing; an optical combiner having a first input port, a second input port, an output port and adapted to receive at the first and second input ports, respectively, the first and the second portions and adapted to output them at said output port; a first optical path optically connecting the first output port of the optical splitter to the first input port of the optical combiner so as to propagate the first portion; a second optical path optically connecting the second output port of the optical splitter to th

Abstract: An optical modulator has an optical splitter for splitting an input light beam into a first and second light beam; a first and a second wave-guide arm connected to the optical splitter for receiving and transmitting therethrough the first and second light beam, respectively, the waveguide arms each including a core region having group IV semiconductor material or a combination of group IV semiconductor materials; an optical combiner connected to the first and second waveguide arm for receiving the first and second light beam and combining them into an output light beam; a first and a second electrode structure associated with the first and second waveguide arm, respectively; and a driving circuit for supplying voltage to the first and second electrode structure. The driving circuit is adapted to supply a first modulation voltage super-imposed to a first bias voltage to the first electrode structure and a second modulation voltage superimposed to a second bias voltage to the second electrode structure.

Abstract: A method for switching from a first optical path optically coupled to an optical processing device to a second optical path, the first and second optical paths optically connecting, in parallel configuration, a first optical switch to a second optical switch, according to the following steps: directing optical radiation comprising at least a fast operating wavelength through the first optical path to the optical processing device, which is tuned to the first operating wavelength; tuning a resonant all-pass filter optically coupled to the second optical path so as to match, at least at a wavelength adjacent to the first operating wavelength, a phase distortion introduced by the optical processing device on the optical radiation; synchronously actuating the first and the second optical switch so as to switch the optical radiation from the first optical path to the second optical path.

Abstract: Bidirectional isolating devices including non-reciprocal rotators (i.e. Faraday rotators) and wavelength selective reciprocal polarization rotators are disclosed. Each wavelength selective rotator behaves like a half-wave retarder in a first frequency range and behaves like a full-wave retarder in a second frequency range, according to a substantially periodic transfer function. The rotation has a predetermined number of birefringent elements (e.g. waveplates), the thickness and the orientation of which are chosen so as to obtain a transition between the half-wave retarder behavior and the full-wave retarder behavior in a frequency range lower than or equal to 40% of the period of the transfer function. In order to satisfy such a requirement, a relatively high number of birefringent elements is required, i.e. at least the five birefringent elements. Advantageously, the isolating device may comply with any allocation scheme for the opposite propagating signals.