Cisco Technology, Inc.

Pirelli Cavi E Sistemi S.p.a.

Corning O.t.i. Spa

Silvia Turolla

Giovanni Marenco

Claudio Crognale

Fausto Meli

Fabrizio Di Pasquale

Giovanni Sacchi

Maurizio Di Vizio

Stefano Piciaccia

Gianpaolo Barozzi

Davide Sirtori

Stefano Aina

Alberto Zermani

Methods for configuring an optical link in which a distribution of transmission data rates and line rates are configured for a predetermined amount of optical bandwidth to maximize transmission capacity. In these methods, a controller of an optical network obtains input parameters that include a signal-to-noise ratio (SNR) for optical signals and an allocated bandwidth of the optical link, further obtains, for each line rate, a mapping of transmission data rates along a frequency spectrum of the allocated bandwidth compatible with the SNR, and generates a channel plan in which a number of traffic modes and a distribution of a plurality of channels in the allocated bandwidth are set to maximize transmission capacity. The plurality of channels is used for transmitting the signals on the optical link. The controller configures at least one optical network element in the optical network to establish the optical link based on the channel plan.

Optical channel plan process

Methods for configuring an optical link with an optimized spectral efficiency are provided. In these methods, a controller of an optical network obtains a baseline configuration that includes a traffic mode that uses a predetermined channel spacing of a plurality of channels in a frequency spectrum. The plurality of channels is used for transmitting optical signals on an optical link in the optical network. The controller further converts the SNR-margin to a Q-margin threshold value associated with a Q-margin as a performance parameter and while maintaining the performance parameter with a predetermined range of the Q-margin threshold value, varies at least one transmission parameter to reduce channel spacing. The controller also generates a spectral frequency map in which the channel spacing is reduced with respect to the baseline configuration and configures, via an optical network element in the optical network, the optical link based on the spectral frequency map.

Bisection searching algorithm to derive optimum baud rate with maximum spectral efficiency exploiting Q-margin-to-SNR-margin conversion

An optical amplifying unit ( ) for amplifying optical signals in an optical transmission system has an amplification wavelength band with a lower wavelength limit greater than 1570 nm and includes an input ( ) for the input of optical signals, an output ( ) for the output of optical signals and an optical amplifier ( ) interposed between the input ( ) and the output ( ) to amplify the optical signals. The optical amplifier ( ) includes an amplification fiber ( ) co-doped with erbium and ytterbium, at least a pump source ( ) to generate pump radiation and at least an optical coupler ( ) optically coupling the pump sources ( ) to the amplification fiber ( ). The optical amplifying unit has a power gain of at least 31 dB when the optical signals have an input power of at least &minus;10.5 dBm and wavelengths within the amplification wavelength band.

Optical amplifying unit and optical transmission system

An approach for minimizing four-wave mixing (FWM) cross-talk (XT) in a WDM (wavelength division multiplexing) optical communication system is disclosed. An Erbium doped Fiber Amplifier (EDFA) includes a pre-amplifier that receives an input optical signal and outputs an amplified input optical signal. The pre-amplifier includes the following components: a first active fiber that carries WDM signals corresponding to a particular operating band (e.g., L-band); a co-propagating pump laser that induces high inversion in a portion of the first active fiber; a filter that is coupled to the first active fiber and slightly inverts the gain tilt of the WDM signals and suppresses the amplified spontaneous emission (ASE) lights accumulated at wavelengths shorter than the signal bandwidth; a second active fiber that is coupled to the filter; and a counter-propagating pump laser that induces high inversion in a portion of the second active fiber. An optical unit (e.g., an optical add/drop module, a gain equalizing filter (GEF), or a dispersion compensating fiber (DCF)) may be coupled to the pre-amplifier and receives the amplified input signal, in which the optical unit introduces a prescribed loss to the WDM system. A booster amplifier is coupled to the optical unit and is configured to amplify a signal that is output from the optical unit. An automatic optical gain control (AOGC) mechanism of the EDFA provides nearly constant gain that is independent of the number of channels utilized in the WDM system and also minimizes system penalties due to fast relaxation oscillations induced by adding/dropping of channels.

All-optical gain controlled L-band EDFA structure with reduced four-wave mixing cross-talk

An optical transmission system has been designed to optimize the use of the spectral emission range of rare-earth-doped fiber amplifiers. The system includes a wide band of channels in the spectral emission range of erbium-doped fiber amplifiers, which is split into two sub-bands, a low sub-band corresponding to the low end of the range and a high sub-band corresponding to the high end of the range. The two sub-bands are separately amplified and optimized, and then recombined without significant competition between the two sub-bands. In addition, an equalizing filter, such as a specialized Bragg filter or interferential filter, is applied to the low sub-band instead of the entire band of channels, thus greatly reducing any equalization need or unequalization effects. In an optical line amplifier for the system, the wide band is amplified in a first stage of a fiber amplifier that operates in a linear condition, the wide band is split into the two sub-bands, and one or the two sub-bands is amplified with the second stage of the fiber amplifier that operates in a saturation condition.

Multi-band amplification system for dense wavelength division multiplexing

Growing community of inventors

Seriate, Italy

Silvia Turolla