Telefonaktiebolaget Lm Ericsson (publ)

Francesco Fresi

Fabio Cavaliere

Luca Poti

Gianluca Meloni

Antonella Bogoni

Enrico Forestieri

Marco Secondini

Gianluca Berrettini

Mirco Scaffardi

Antonio Malacarne

Vito Sorianello

Tommaso Foggi

Tommaso Catuogno

Emma Lazzeri

A method () of encoding communications traffic bits onto an optical carrier signal in a pulse amplitude modulation, PAM, format. The method comprises: receiving () bits to be transmitted; receiving () an optical carrier signal comprising optical pulses having an amplitude and respective phases; performing () PAM of the optical pulses to encode at least one respective bit in one of a pre-set plurality of amplitudes of a said optical pulse; and performing () phase modulation of the optical pulses to encode at least one further respective bit in a phase difference between a said optical pulse and a consecutive optical pulse.

Encoding and decoding communications traffic in a pulse amplitude modulation format and optical apparatus for same

A method for dual polarisation optical transmission is disclosed. The method comprises splitting a continuous wave light source into first and second sub-channels, optically modulating each sub-channel with a data signal, and superimposing a first pilot tone onto the first optically modulated sub-channel and a second pilot tone, different from the first pilot tone, onto the second optically modulated sub-channel. The method further comprises polarisation multiplexing the first and second sub-channels to form a polarisation multiplexed signal, in which the first and second sub-channels have orthogonal states of polarisation, and transmitting the polarisation multiplexed signal.

Methods and apparatus for dual polarisation optical communication

An optical transmission method () comprising steps of receiving () a communication signal comprising symbols for transmission. The method comprises performing () linear amplitude modulation of an optical carrier with the communication signal to generate an amplitude modulated optical carrier. The method comprises performing low-pass filtering () to reduce a bandwidth of the symbols to less than a Nyquist bandwidth of the symbols. The method comprises transmitting () the amplitude modulated optical carrier. The method further comprises receiving () the amplitude modulated optical carrier following transmission and performing direct detection of the received amplitude modulated optical carrier to generate a received electrical signal; and determining () received symbols from the received electrical signal using an indication of a nonlinear impulse response of the direct detection.

Optical transmission method and optical receiver apparatus for determining received symbols from a received electrical signal using an indication of a nonlinear impulse response of the direct detection and without performing equalization following the direct detection

A method of controlling a parameter in the generation of a coherent optical signal, the method comprising the steps of: receiving a set of signal samples relating to detection of a coherent optical signal; transforming the set of signal samples into a set of spectrum samples in the frequency domain, the set of spectrum samples being an estimation of the spectrum of the coherent optical signal; calculating at least one feedback variable based on the spectrum samples; and adjusting the parameter based on the at least one feedback variable.

Method of controlling the generation of a coherent optical signal and coherent optical signal control apparatus

An analogue to digital converter is arranged to receive and process an analogue optical input signal to produce an N bit digital optical output signal quantised to 2levels, where N is greater than or equal to 2. The converter has an input for receiving the optical input signal and N processing channels which are each coupled to the input, at least one of said processing channels comprising an optical processing circuit arranged to generate a plurality of digital optical output signals. The optical processing circuit is arranged to change the state of each digital optical output signal corresponding to a respective different value of the analogue optical input signal, and an optical combining circuit for combining the optical output signals in order to generate one bit of the N-bit digital optical signal.

Optical analogue to digital converter

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Pisa, Italy

Francesco Fresi