Abstract: A method of phase modulating optical radiation by the steps of phase modulating the optical radiation by using a modulator having an extinction ratio in order to provide a multilevel phase shift key signal, and applying to each optical pulse a phase-shift having an absolute value depending on the extinction ratio and a sign depending, for each of the optical pulses, on the respective optical phase value. An apparatus implementing the method is also disclosed.

Abstract: A filter for an optical fibre temperature sensor comprising at least one first and one second optical filter for filtering an optical pulse reflected by said optical fibre, characterised in that said at least one first and one second optical filter comprise standard commercial filters complying with ITU specifications, said optical pulse lying within the range from 1570 nm to 1580 nm.

Abstract: An optical communication system (100; 2300) comprises at least a transmitter (110) apt to emit a differential phase shift keying (DPSK) optical signal having a bit-rate equal to R, at least a receiving system (1200) for receiving the differential phase shift keying optical signal; and an optical link (130) optically connecting the transmitter and the receiving system for transmitting the DPSK optical signal from the transmitter to the receiving system, wherein the receiving system comprises a coherent optical receiving device (1205) apt to coherently receive the propagated DPSK optical signal and to emit at least one electrical signal (I) related to the received DPSK optical signal, and wherein the receiving system further comprises at least one electrical filter (270) for filtering the at least one electrical signal and having ?3 dB double-side bandwidth greater than or equal to 0.44 R and lower than or equal to 0.68 R, and at least one squarer (280) for squaring the at least one filtered electrical signal.

Abstract: An optical transmission system having an optical source, an optical dispersion compensation filter optically connected to the optical source, and a control system. The optical source generates a modulated optical signal having an optical spectrum and a value of dispersion robustness. The optical dispersion compensation filter has at least two cascaded optical resonators and a periodic transfer function rigidly translatable in the frequency spectrum to obtain translation in frequency of the transfer function without a substantial change in shape, and characterized by a free spectral range. The control system acts on the optical dispersion compensation filter in order to rigidly translate the transfer function along the frequency spectrum in first and second positions in the frequency spectrum. The translation of the transfer function between the first and the second positions is smaller than the free spectral range.

Abstract: A device and method for stabilizing the state of polarization of polarization multiplexed optical radiation including an identified channel is disclosed.

Abstract: A method of phase modulating optical radiation by the steps of phase modulating the optical radiation by using a modulator having an extinction ratio in order to provide a multilevel phase shift key signal, and applying to each optical pulse a phase-shift having an absolute value depending on the extinction ratio and a sign depending, for each of the optical pulses, on the respective optical phase value. An apparatus implementing the method is also disclosed.

Abstract: A method of phase modulating optical radiation by the steps of phase modulating the optical radiation by using a modulator having an extinction ratio in order to provide a multilevel phase shift key signal, and applying to each optical pulse a phase-shift having an absolute value depending on the extinction ratio and a sign depending, for each of the optical pulses, on the respective optical phase value. An apparatus implementing the method is also disclosed.

Abstract: A device and method for stabilizing the state of polarization of polarization multiplexed optical radiation including an identified channel is disclosed.

Abstract: A device and method for stabilizing the polarization of polarization multiplexed optical radiation includes an identified channel which is provided with a pilot signal.

Abstract: A filter for an optical fibre temperature sensor comprising at least one first and one second optical filter for filtering an optical pulse reflected by said optical fibre, characterised in that said at least one first and one second optical filter comprise standard commercial filters complying with ITU specifications, said optical pulse lying within the range from 1570 nm to 1580 nm.

Abstract: An optical communication system (100; 2300) comprises at least a transmitter (110) apt to emit a differential phase shift keying (DPSK) optical signal having a bit-rate equal to R, at least a receiving system (1200) for receiving the differential phase shift keying optical signal; and an optical link (130) optically connecting the transmitter and the receiving system for transmitting the DPSK optical signal from the transmitter to the receiving system, wherein the receiving system comprises a coherent optical receiving device (1205) apt to coherently receive the propagated DPSK optical signal and to emit at least one electrical signal (I) related to the received DPSK optical signal, and wherein the receiving system further comprises at least one electrical filter (270) for filtering the at least one electrical signal and having ?3 dB double-side bandwidth greater than or equal to 0.44 R and lower than or equal to 0.68 R, and at least one squarer (280) for squaring the at least one filtered electrical signal.

Abstract: Optical transmission system (200) comprising: an optical source (210) adapted to generate a modulated optical signal having an optical spectrum and a dispersion robustness; an optical dispersion compensation filter (250) optically connected to the optical source, comprising at least two cascaded optical resonators and having a periodic transfer function that is rigidly translatable in the frequency spectrum and characterized by a free spectral range (FSR); a control system (270; 280; 260) adapted to act on the optical compensation filter in order rigidly to translate said transfer function along the frequency spectrum in a first and in a second position in such a way that: in a first position in the frequency spectrum of said transfer function, the mean chromatic dispersion weighted over said optical spectrum of the modulated signal is greater, in absolute value, than the value of dispersion robustness; in a second position in the frequency spectrum of said transfer function, the mean chromatic dispersion wei

Abstract: A device and method for stabilizing the polarization of polarization multiplexed optical radiation includes an identified channel which is provided with a pilot signal.

Abstract: A method of phase modulating optical radiation by the steps of phase modulating the optical radiation by using a modulator having an extinction ratio in order to provide a multilevel phase shift key signal, and applying to each optical pulse a phase-shift having an absolute value depending on the extinction ratio and a sign depending, for each of the optical pulses, on the respective optical phase value. An apparatus implementing the method is also disclosed.

Abstract: A crystal made of CdxZn1−xTe provides an electro-optical switch that performs consistently at high and low switching frequencies for signals of the 1000-1650 nm wavelength window. Preferably, a crystal of Cd0.9Zn0.1Te is driven with an electrical voltage to cause polarization rotation and switching action for a passing optical signal. Despite having a higher light absorption coefficient than CdTe:In, Cd0.9Zn0.1Te surprisingly exhibits a weak auto-inhibition effect, giving it better electro-optic performance when used in conjunction with optical wavelengths and optical powers characteristic of optical communication systems. Optical switch matrices and optical cross-connect switches in optical communication systems may effectively use Cd0.9Zn0.1Te crystals.

Abstract: An optical window signal generator which begins generation of an optical output signal in response to an optical activation pulse, and terminates generation of the optical output signal in response to an optical deactivation pulse. The rise time of the optical output signal is equal to the rise time of the optical activation pulse, and its fall time is equal to the rise time of the optical deactivation pulse.

Abstract: An optical device having a first input for at least one input optical signal having a random state of polarization and a first optical element capable of dividing, in space, the input optical signal into a pair of optical signals which are substantially parallel and have a predetermined state of polarization perpendicular to each another. The optical device also having a first crystal element for propagation, in free space, of at least the pair of optical signals coming from the first optical element, and the first crystal element being devoid of internal separation planes, and having electro-optical properties and being associated with electrodes so as to apply a voltage in a direction substantially perpendicular to the direction of propagation, along the first crystal element, of the at least one pair of optical signals.

Abstract: An optical device for processing a digital optical signal in parallel and in free space, the said device comprising:

Abstract: An optical device is provided for processing a digital optical signal in parallel and in free space. A device consistent with the invention provides for inputting a digital optical signal in guided propagation, converting the digital optical signal to n digital optical signals in guided propagation, and converting the n digital optical signals to n digital optical signals in free space. In addition, the invention provides for selecting a bit preselected from the at least one temporal series of n bits of each of the n digital optical signals, modifying optically, at least one bit of the spatial figure of the n bits, and outputting the at least one bit of the spatial figure of n bits.

Abstract: An optical device to perform an asynchronous and parallel processing of a N bits serial stream of an optical digital signal comprises a) a serial to parallel converter which converts the serial stream of N bits into a first parallel pattern of N bits carrying the same information as the serial stream of N bits; b) an optical system to produce, from the parallel pattern of N bits, a first two-dimensional (2-D) image made of N rows and M columns (N×M) of bits, each column being associated to the digital optical signal by a predetermined relationship; c) a logic device to perform logic operations on the bits of the first 2-D image; and d) a device to send to an output the results of the logic operations.