Pirelli Cavi S.p.a.

Pirelli & C. S. P. A.

Cisco Photonics Italy S.r.l.

Cisco Technology, Inc.

Pierluigi Franco

Giorgio Grasso

Marco Romagnoli

Flavio Fontana

Matjaz Vidmar

Luciano Socci

Silvia Ghidini

Francesco Maria Tassone

Michele Midrio

Roberto Aldeghi

Ilaria Cristiani

Point-to-point link for the transmission of digital signals includes two opto-electronic conversion apparatuses and an optical cable including at least one optical fiber having two terminal portions, each opto-electronic conversion apparatus including an opto-electronic device optically coupled to a respective terminal portion between the two terminal portions of the at least one optical fiber, wherein at least one of the two opto-electronic conversion apparatuses is adapted to keep the respective terminal portion of the optical fiber in bent position with a bending radius R, where 1.5 mm&#x2266;R&#x2266;2.5 mm, and to keep the respective opto-electronic device optically coupled to the bent terminal portion in order to allow the transmission of the digital signals between the optical fiber and the at least one of the two opto-electronic conversion apparatuses; and at least the bent terminal portion of the at least one optical fiber is such as to satisfy the following relationship r/R&#x3c;0.07*n/(35+n), where n is the stress corrosion susceptibility factor and r is the radius of the cladding of the optical fiber.

Point-to-point optical fibre link

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.

Optical devices comprising series of birefringent waveplates

At a receiver a 20 Gbit/s soliton bit stream () is demultiplexed into two 10 Gbit/s bit streams () using a 2-way splitter (), a clock extraction circuit (), and a pair of polarization insensitive amplitude modulators () exhibiting positive chirp. The outputs of the modulators are fed to detectors () via lengths () of optical fiber exhibiting normal dispersion thereby producing bit streams () with increased mark/space ratio and reduced timing jitter.

System and method of high-speed transmission and appropriate transmission apparatus

Soliton or soliton-like optical pulses with characteristics adapted to propagation in an optical line for RZ type transmission are generated by modulating a continuous optical signal () by means of a modulator () which is substantially devoid of chirping, in which the modulator drive signal comprises at least one frequency () and one harmonic () thereof superimposed on each other (). A high-speed optical transmission system is rendered independent of the type of transmitter or of signals sent to it if it comprises an adaptation unit () receiving the original optical pulses () and capable of generating corresponding pulsed signals () of RZ type.

A system for providing noise reduction in a long-distance telecommunications system is disclosed. A transmitter generates an optical signal. An optical link includes an optical amplifier that transmits the optical signal in a pre-established direction of propagation with substantially compensated dispersion to have an associated optical noise. A receiver is configured to receive a noisy optical signal including the transmitted optical signal and an optical noise signal. The receiver includes a photodetecting device that is configured to generate an electronic signal correlated with the noisy optical signal. The electronic signal being associated with a quality parameter (Q) that depends on said optical noise signal and distortion of the optical signal in the optical link. The optical link further includes a dispersive and nonlinear filtering device that has a normal dispersion and nonlinear component. The filtering device is placed along said optical link and has an associated normal dispersion parameter &bgr; &bull;L and a nonlinearity parameter &ggr; operatively selected so as to increase the quality parameter by at least 1 dB.

Method for the reduction of noise in a long-distance optical telecommunications system

The device and method are based on tapping off a predetermined line signal fraction and inputting it, together with a continuous pumping radiation, to a resonant cavity which comprises a non-linear wave guide. The value of the pumping wavelength is related to the wavelength of the line signal pulses to produce therewith a four-wave mixing (FWM) effect in the non-linear wave guide. In travelling the non-linear wave guide, a clone signal is generated by FWM effect which duplicates the pulse sequence of the line signal at a clone wavelength. By adjusting the length of the resonant cavity such that, in inputting the line signal, each of its pulses will come in at exactly a pulse of the clone signal which is being circulated within the cavity, a clone signal can be circulated within the resonant cavity whose pulse sequence represents the optical clock signal sought.

Method and device for optically recovering the synchronism of an optical

A high-transmission-speed optical connection comprising a pulse-generation laser source, optical-fibre transmission means and a receiver, in which said optical-fibre means forms an optical fibre path, such that a pulsed signal of the soliton type is subjected to a broadening in time greater than 50% by effect of the chromatic dispersion, in which said laser source comprises an active and harmonic mode-locking optical-fibre laser wherein the fibre length, filter pass-band and power in the cavity are selected for emitting pulses of a Gaussian temporal profile having such a duration and bandwidth that, at the receiver, the duration of the pulses themselves is not more than 15% higher than the duration at the emission.

Growing community of inventors

Padua, Italy

Pierluigi Franco