Abstract: The present invention is a device to increase the bit rate and distance at which data can be transmitted by optical fiber. The device compensates the polarization dispersion of the line by processing a received optical signal with the use of a polarization controller, the generation of a differential group delay between two orthogonal polarization modes and a control unit for the polarization controller. The data that is sent is redundant to enable detection of errors affecting the data received and the control unit is adapted to minimize the error rate calculated in real time by using the redundant data. The application of the device is to long-haul optical transmission, in particular over stranded fibers.

Abstract: The invention concerns a fiber optic soliton signal transmission system comprising a signal amplifier means and signal regenerator means, in-line first filter means and second filter means associated with the regenerator means, the second filter means being different from the first filter means. Independent optimization of the in-line filter means and the filter means associated with the regenerator improves the performance of the transmission system. In the case of wavelength division multiplexed systems, the invention reduces the effects of jitter induced by collisions between solitons.

Abstract: Apparatus for recovering clock pulses of wavelength division multiplexed optical signals passed therethrough. The apparatus comprises an optically-pumped laser cavity defining a cavity length and comprising a nonlinear medium pumped at a wavelength selected to give efficient parametric amplification within said medium. The cavity length corresponds to an integer multiple of bit periods of at least one of the multiplexed optical signals. The optical signals copropagate through the medium with the pump radiation. The apparatus further comprises an optical path for recirculating a proportion of the output from the laser cavity back through the laser cavity. In this way, idler waves are generated symmetrically about the pump wavelength by four wave mixing with the at least one of the multiplexed optical signals and recirculated through the laser cavity to be amplified by parametric amplification in order to recover wavelength division multiplexed clock pulses.

Abstract: A method for remodulation of a modulated optical signal is disclosed which uses a disturbed line signal and an optical clock signal derived from the undisturbed original line signal modulated with the bitrate frequency feeding both signals in a Raman amplifying fiber connected to at least one Raman pump running the clock signal as Raman pump wavelength for the line signal.

Abstract: A jitter compensator apparatus is provided having a phase modulator for receiving jittered pulses and a clock recovery device for locally recovering a clock signal. The phase modulator is driven in synchronism by the the locally recovered clock signal and is adapted to provide a frequency shift to the jittered pulses proportional to the jitter displacement of each of the jittered pulses.

Abstract: An optical translator that includes an interferometer and a plurality of semiconductor optical amplifiers (SOAs) coupled to the interferometer. The at least two of the SOAs receives data and a clock signal. The data is received by the at least two SOAs at different times. A coupler combines each of a respective output of the at least two SOAs to provide output data. The output data is a retimed and a reshaped signal of the data provided to at least one of the plurality of SOAs.

Abstract: An out of band vehicle for an optical network is used for transporting overhead (OH) data between 3R network elements, irrespective of the format or/and rate of the OH data. At the first 3R network element, the OH data is up-converted at a frequency fch, and the resulting signal is combined with the traffic and transmitted to a second 3R network element. The inverse operation is effected at the second 3R network element by down-converting the combined signal. The frequency fch is selected to be in a null of the traffic spectrum, so as to not interfere with the traffic.

Abstract: When a PLL circuit is used to extract and recover clock component from an information data signal, where an optical receive signal has been converted into an electrical signal, and to monitor the frequency of a recovered clock, a low frequency section frequency detection circuit having a BPF (band-pass filter) where transmission center frequency has been shifted to higher frequency relative to center frequency of the electrical signal and a high frequency section frequency detection circuit having a BPF where the transmission center frequency has been shifted to lower frequency are provided in parallel. Utilizing a slope on one side of each transmission characteristic of the BPF makes it possible to set detection frequency freely and accurately. Therefore, a frequency detection circuit without using a special device in an optical transmitter/receiver, capable of easily detecting accurate frequency shift of f0±&Dgr;f or more, and of low price and high performance, can be obtained.