Alcatel

Alcatel Submarine Networks

Alcatel Lucent

Georges Grandpierre

Eric Brandon

Loïc Becouarn

Roland Uhel

Francois Lafranca

Thierry Boissau

A demodulator for a DPSK-modulated optical signal of bit frequency 1/T, comprises an interferometric structure () having an input port () for receiving the DPSK-modulated optical signal, an output port (), and first and second arms () extending from said input port () to said output port (), adjustment means () for fine tuning a propagation delay difference of said two arms () in a range comprising T, an optical/electrical converter () connected to the output port () of the interferometric structure (), and a bandpass filter () connected to an output of the optical/electrical converter (), the passband of which does not include 1/T. The adjustment means () is adapted to tune the propagation delay according to the output power level of the bandpass filter ().

DPSK demodulator and demodulating method

An emitter of optical signals for optical fibers includes an electroabsorption modulator downstream of a laser and a Mach-Zhender modulator downstream of the electroabsorption modulator and controlled by at least one clock to eliminate for each pulse of the resulting signal from the first modulator a portion of signal in a time range including the rising edge and in a time range including the falling edge.

Signal emitter for optical fibers

The present invention relates to a method of generating a clock signal of exact phase from an optical input signal that is divided up optically into two channels, one for data extraction to generate an electrical data signal and one for clock extraction to generate an electrical first clock signal, so that the phase position of the first clock signal is corrected by comparison with the phase position of the data signal so that the phase position of the resulting clock signal formed after this correction is similar to the phase position of the data signal, and also a digital optical receiver therefor.

Method of generating a clock signal of exact phase from an optical input signal and optical receiver therefor

A receiver for digital optical signals, in particular in the soliton format, includes an automatic gain control amplifier and photodetectors for converting the optical signals into electrical signals in a data channel and a clock channel. For detecting signals transmitted optically at high bit rates, the automatic gain control amplifier is an optical amplifier and is on the input side of the photodetectors. There are preferably two photodetectors, the first of which is connected to a data processing channel and the second of which is connected to a clock signal recovery channel. This receiver can receive signals at bit rates exceeding 10 Gbit/s.

Receiver for optical digital transmission system

The invention provides a circuit for amplitude modulating an optical signal with an N-state electrical signal where N is greater than or equal to 2, the circuit comprising a modulator having a first input for receiving the optical signal to be modulated and a second input for receiving a modulating electrical signal. According to the invention, the circuit comprises, upstream from the second input, shaping component having an input receiving the N-state electrical signal and having an output that switches from one of the N states to another of the N states in response to the N-state electrical signal taking up a level that is greater than a predetermined threshold, and switching from the other state to the one of the N states in response to the N-state electrical signal taking up a level that is less than the predetermined threshold, the predetermined threshold being associated with the pair of states, and having a level that lies between and is different from the respective levels taken by the two states.

Growing community of inventors

Arpajon, France

Georges Grandpierre