Cisco Technology, Inc.

Carlo Tosetti

Damiano Rossetti

Carlo Mariotti

Federico Fontanella

Giuseppe Pietro Ravasio

Gilberto Loprieno

Marco Mazzini

Alessandro Cavaciuti

Gianpaolo Barozzi

A method of measuring lengths of optical fibers on forward and return paths is provided in order to synchronize clocks of optical nodes connected by asymmetrical optical fiber paths. The method includes calculating, by a first optical network device, a first propagation delay of a first optical signal transmitted at a first wavelength on a first optical fiber to the first optical network device from a second optical network device and a second propagation delay of a second optical signal transmitted at a second wavelength on the first optical fiber to the first optical network device from the second optical network device. The second wavelength is different from the first wavelength. The method further includes determining, by the first optical network device, a first length of the first optical fiber based on the first propagation delay and the second propagation delay.

Optimizing clock synchronization of optical nodes connected by asymmetric optical fibers

A method is provided to lower the overall power consumption of small form-factor pluggable (SFP) transceivers. The method includes receiving an indication to operate the SFP transceiver in a low power mode, and setting the SFP transceiver to a low power mode in response to the indication by at least switching off a thermal electric cooler (TEC) that controls a temperature of a laser diode of the SFP transceiver. The proposed method may be implemented whenever a reach is not more than a predetermined distance, for example, 65 kilometers. At such reduced distances, the TEC of the SFP transceiver can be switched off while still guaranteeing link functionality. The instant low power mode has the benefit of reducing the power consumption of the SFP transceiver so that, for example, host platforms with lower power delivery budgets can support the SFP transceiver for at least some applications.

Low power consumption small form-factor pluggable transceiver

Method and apparatus for operating for operating an optical network including a shared laser array are disclosed. An example apparatus includes include a first plurality of N lasers. Each laser of the first plurality of N lasers is configured to output a respective optical seed signal having a respective wavelength. The example apparatus further includes a first optical coupler coupled with the first plurality of N lasers. In the example embodiment, the first optical coupler is configured to multiplex the respective optical seed signals of the first plurality of N lasers onto a plurality of N optical fibers. In this example, each optical fiber of first plurality of N optical fibers transmits each of the respective optical seed signals produced by the plurality of N lasers to a respective distribution node for distribution to N respective optical network units, where the optical network units use the optical seed signals to seed respective optical transmitters located at the N optical network units.

Optical network with shared laser array

An apparatus for connecting a host device to an optical network, and to provide a bi-directional electro-optic interface to the host device. The apparatus comprises at least one optical network port for connection to the optical network, and a transceiver circuit configured to generate optical transmit signals for transmission via the at least one network port. The transceiver circuit is further configured to process optical receive signals received via the network port. The apparatus further comprises an optical connector configured to provide bi-directional transfer of optical data signals with the host device.

Pluggable module with bi-directional host-module optical interface

Various example embodiments are disclosed. According to an example embodiment, a dual split passive optical network (PON) may be provided that includes an optical splitting device, and a first and second distribution fibers connected to the optical splitting device. A first cyclic AWG may be coupled to the optical splitting device via the first distribution fiber and a second cyclic AWG may be coupled to the optical splitting device via the second distribution fiber. In other example embodiments, an asymmetric power splitting ratio may be used for the splitting device, or optical seeds and/or optical data signals may be allocated to each of the cyclic AWGs based on a performance of the optical data signals and/or power loss/attenuation of the respective distribution fibers.

Split/smart channel allocated WDM-PON architecture

A link probe for multimode fibers in optical networks is provided. An optical test probe signal is sent over a multimode fiber of an optical network link and a receiver converts the optical signal into an electronic signal with a trigger generated by the clock recovery section of an EDC (electronic dispersion compensation) unit. The digital signal is processed by a modified IEEE algorithm to determine a TWDP (Transmitter and Waveform Dispersion Penalty) parameter which quantifies the transmission quality of the multimode fiber and link suitability to LRM transmission.

Multimode fiber link probe

Various example embodiments are disclosed. According to one example embodiment, a method may include transmitting a semiconductor laser-generated optical signal from a first end of a multi-mode fiber (MMF) optical link to a second end of the link. The optical signal may have a reference bandwidth at the first end of the link. The method may further include converting the optical signal to an electrical signal. The method may further include analyzing the electrical signal with an electronic dispersion compensator to determine an effective modal bandwidth (EMBW) of the received optical signal. The method may further include analyzing the electrical signal with an electronic dispersion compensator to determine an intersymbol interference (ISI) penalty of the optical link. The method may further include comparing the EMBW and the ISI penalty to predetermined threshold values of a tolerable EMBW and a tolerable ISI penalty, respectively, to characterize the optical link as acceptable or unacceptable for use as a communications link with a predetermined communications protocol.

Optical link characterization

Methods and apparatus for supporting a plurality of modulation formats using a single transmitter are disclosed. According to one aspect of the present invention, a transmitter arrangement that provides a signal to a modulator that creates an optical data stream from the signal includes an encoder and a switching/filtering arrangement. The encoder has a state that is varied between first and second encoder states. If the state is the first encoder state, the encoder encodes the signal in a format associated with an optical duobinary (ODB) modulation format. Otherwise, the encoder does not encode the signal in the format associated with the ODB modulation format. The switching/filtering arrangement receives the signal from the encoder, and provides the signal to the modulator. If the variable state of the encoder is the first encoder state, the switching/filtering arrangement has a low bandpass configuration. Otherwise, the switching/filtering arrangement has a high bandpass configuration.

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Sondrio, Italy

Carlo Tosetti