Future Wei Technologies, Inc.

Huawei Technologies Co., Limited

Jian Zhong

Zhiping Jiang

Yan Cui

Rui Bang He

The application provides a method for measuring a dispersion coefficient of an optical fiber. A network device sends a first optical supervisory channel (OSC) measurement signal and a second OSC measurement signal, where wavelengths of the first OSC measurement signal and the second OSC measurement signal are different. The network device receives the returned first OSC measurement signal and second OSC measurement signal, where the first OSC measurement signal and the second OSC measurement signal are transmitted through a first optical fiber and a second optical fiber to return to the network device, and the first optical fiber and the second optical fiber are a to-be-tested optical fiber. The network device determines a delay difference between the received first OSC measurement signal and second OSC measurement signal. The network device determines a dispersion coefficient of the to-be-tested optical fiber based on the delay difference.

Method for measuring dispersion coefficient of optical fiber and network device

An apparatus comprising a processor configured to calculate a noise figure of an optical amplifier for a plurality of selected wavelength channels in a partial-fill scenario that accounts for channel loading. The noise figure is calculated using a plurality of corresponding noise figure correction values at a plurality of wavelengths based on an effective number of channels.

Apparatus and method to calculate a noise figure of an optical amplifier for wavelength channels in a partial-fill scenario to account for channel loading

System, apparatus, and method embodiments are provided for suppressing the stimulated Raman scattering (SRS) crosstalk in multiple wavelength channel signals propagating in fiber links, such as in WDM/DWDM or other optical communications systems. The SRS is reduced or suppressed by separating the channels into two sets of different channels, such as even and odd channels, and then performing subtraction of signal amplitudes between the two sets of channels. The channels are separated by an interleaver into the two sets. Alternatively, a wavelength selective switch (WSS) is used to separate the channels into the two sets on which the subtraction of signal amplitudes is then performed. In an embodiment, the signals are low frequency modulation signals used for channel monitoring for optical communications systems.

System and method for reducing the stimulated Raman scattering crosstalk in channel monitoring

Embodiments are provided for applying pilot tone modulations to optical signals by introducing bias bits to data frames carried on the optical signals. Since the modulation is done by modifying data, the modulation depth is accurate, and there is no need for calibration or feedback control, which can improve power monitoring accuracy and simplify implementation. In an embodiment, a transmitter determines a period of a pilot tone modulation for tracking or identifying an optical channel. The transmitter inserts a sequence of bias bits, periodically according to the determined period, in a plurality of frames comprising original data bits. The amplitudes of the optical signals carrying the frames are modulated at a higher frequency than the pilot tone modulation. The optical signals are then transmitted including the bias bits within the frames.

System and method for pilot tone modulation by data bias

An apparatus comprising a plurality of switches coupled to a plurality of corresponding colorless laser transmitters, an odd channel coupler coupled to each of the switches, an even channel coupler coupled to each of the switches, and an interleaver coupled to the odd channel coupler and the even channel coupler. Also disclosed is an apparatus comprising a coupler coupled to a plurality of colorless laser transmitters, a first interleaver coupled to the coupler, and a second interleaver coupled to the first interleaver. Also disclosed is an apparatus comprising an odd channel coupler coupled to a plurality of first laser transmitters, an even channel coupler coupled to a plurality of second laser transmitters, and an interleaver coupled to the odd channel coupler and the even channel coupler.

Method and apparatus for colorless add

An apparatus comprising one or more optical amplifiers coupled to an optical link and configured to amplify a plurality of Wavelength Division Multiplexing (WDM) channels that are transmitted at a plurality of wavelengths on the optical link, and a processor coupled to the optical link and configured to add, delete, or both a plurality of WDM channels in the optical link based on an allowed power ratio indication for the WDM channels, wherein the allowed power ratio indication is calculated based on a plurality of gain change representations for the WDM channels at a plurality of power ratios and on a link budget requirement for the optical link.

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Kanata, Canada

Jian Zhong