Abstract: A system and method for in-service optical dispersion determination are provided. Optical dispersion is determined by splitting a first optical signal into two components, introducing a time delay between the two components such that corresponding pulses of the two components partially overlap, combining the two components to generate a combined optical signal comprising a first component and a second component, determining power of the combined optical signal while applying a plurality of dispersion compensation values, in order to determine a dispersion compensation value that results in a minimum detected power of the combined optical signal. Polarization Mode Dispersion is determined by adjusting the time delay that is introduced until the power of the combined optical signal is substantially equal for all of the plurality of dispersion compensation values.

Abstract: An optical amplifier has a pump and an “anti-pump” for reducing a variation of the amplifier gain with the input optical power. The wavelength of “anti-pump” light is longer than the wavelength of the optical signal being amplified, so that the optical signal serves as a pump for the “anti-pump” light, whereby an optical loss variation with the signal power at the signal wavelength is created, which reduces optical gain variation with the signal power. To compensate for gain loss due to the anti-pump light, two and three stages of amplification can be used.

Abstract: A system and method for in-service optical dispersion determination are provided. Optical dispersion is determined by splitting a first optical signal into two components, introducing a time delay between the two components such that corresponding pulses of the two components partially overlap, combining the two components to generate a combined optical signal comprising a first component and a second component, determining power of the combined optical signal while applying a plurality of dispersion compensation values, in order to determine a dispersion compensation value that results in a minimum detected power of the combined optical signal. Polarization Mode Dispersion is determined by adjusting the time delay that is introduced until the power of the combined optical signal is substantially equal for all of the plurality of dispersion compensation values.

Abstract: A system and method for in-service optical dispersion determination are provided. Optical dispersion is determined by splitting a first optical signal into two components, introducing a time delay between the two components such that corresponding pulses of the two components partially overlap, combining the two components to generate a combined optical signal comprising a first component and a second component, determining power of the combined optical signal while applying a plurality of dispersion compensation values, in order to determine a dispersion compensation value that results in a minimum detected power of the combined optical signal. Polarization Mode Dispersion is determined by adjusting the time delay that is introduced until the power of the combined optical signal is substantially equal for all of the plurality of dispersion compensation values.

Abstract: An optical amplifier has a pump and an “anti-pump” for reducing a variation of the amplifier gain with the input optical power. The wavelength of “anti-pump” light is longer than the wavelength of the optical signal being amplified, so that the optical signal serves as a pump for the “anti-pump” light, whereby an optical loss variation with the signal power at the signal wavelength is created, which reduces optical gain variation with the signal power. To compensate for gain loss due to the anti-pump light, two and three stages of amplification can be used.

Abstract: A system and method for in-service optical dispersion determination are provided. Optical dispersion is determined by splitting a first optical signal into two components, introducing a time delay between the two components such that corresponding pulses of the two components partially overlap, combining the two components to generate a combined optical signal comprising a first component and a second component, determining power of the combined optical signal while applying a plurality of dispersion compensation values, in order to determine a dispersion compensation value that results in a minimum detected power of the combined optical signal. Polarization Mode Dispersion is determined by adjusting the time delay that is introduced until the power of the combined optical signal is substantially equal for all of the plurality of dispersion compensation values.

Abstract: An arrangement has a WDT (Wavelength-Dependent Tap) coupled in an OCS (Optical Communication System) and an OPM (Optical Performance Monitoring) function coupled to the WDT. The WDT is adapted to receive from the OCS an input optical signal having noise and channels at respective channel wavelengths. The WDT couples to an output some of the input optical signal at the channel wavelengths and most of a noise power at wavelengths between the channel wavelengths, and couples a remaining portion of the input optical signal back into the optical communication system. The optical performance monitoring function determines a power characteristic of the input optical signal as a function of a power from the output. The power characteristic may be an OSNR (Optical Signal-to-Noise Ratio) determined as a function of a signal power and a noise power of the output optical signal.

Abstract: A method and a system for dynamic compensating polarization mode dispersion (PMD) in an optical communication system. An optical input signal passes through a compensating element first. A splitting device taps a fraction of the optical input signal and sends it to a monitoring element with birefringence properties. The monitoring element separates the fraction into two split signals with orthogonal principal states of polarization. The split signals are detected at photodetectors. An optimised coefficient is obtained from the detected split signals, and used to calculate an angle between a fast axis of the monitoring element and the fast axis of the optical fiber. The compensating element is set according to the determined angle to compensate the PMD. One or both of the monitoring element and the compensating element may be liquid crystal.

Abstract: An optical amplifier system and controller and a method for automatically controlling the usable signal power of an optical amplifier are provided. The method differentiates between the total optical power that includes the amplified spontaneous emission (ASE), and the useful amplified optical signal power at the output of the amplifier. The optical amplifier system comprises an optical amplifier, a first and a second photodetector operable to measure the power of the input and output signals of the optical amplifier and an amplification controller with a control input. The amplification controller is operable to compensate for the ASE power when operating in automatic signal power control mode.

Abstract: An optical amplification apparatus is provided comprising a plurality of fiber amplification media segments which are concatenated in series wherein subsequent to each fiber amplification media segment one or more wavelengths is dropped so as to exploit a gain versus fiber amplification media physical length characteristic. By exploiting the gain versus fiber amplification media physical length characteristic in such a manner it is possible to achieve a substantially flat gain response for a multi-wavelength output of the optical amplification apparatus. Some embodiments of the invention combine noise suppression and additional gain flattening on one or more wavelengths. Embodiments of the optical amplification apparatus can be used in red-band wavelength range applications of coarse wavelength division multiplexing (CWDM). Some embodiments of the invention also provide that the optical amplification apparatus can be used as a hybrid dense wavelength division multiplexing (DWDM) and CWDM optical amplifier.

Abstract: An optical amplifier system and controller and a method for automatically controlling the usable signal power of an optical amplifier are provided. The method differentiates between the total optical power that includes the amplified spontaneous emission (ASE), and the useful amplified optical signal power at the output of the amplifier. The optical amplifier system comprises an optical amplifier, a first and a second photodetector operable to measure the power of the input and output signals of the optical amplifier and an amplification controller with a control input. The amplification controller is operable to compensate for the ASE power when operating in automatic signal power control mode.

Abstract: An arrangement has a WDT (Wavelength-Dependent Tap) coupled in an OCS (Optical Communication System) and an OPM (Optical Performance Monitoring) function coupled to the WDT. The WDT is adapted to receive from the OCS an input optical signal having noise and channels at respective channel wavelengths. The WDT couples to an output some of the input optical signal at the channel wavelengths and most of a noise power at wavelengths between the channel wavelengths, and couples a remaining portion of the input optical signal back into the optical communication system. The optical performance monitoring function determines a power characteristic of the input optical signal as a function of a power from the output. The power characteristic may be an OSNR (Optical Signal-to-Noise Ratio) determined as a function of a signal power and a noise power of the output optical signal.

Abstract: An optical amplification apparatus is provided comprising a plurality of fiber amplification media segments which are concatenated in series wherein subsequent to each fiber amplification media segment one or more wavelengths is dropped so as to exploit a gain versus fiber amplification media physical length characteristic. By exploiting the gain versus fiber amplification media physical length characteristic in such a manner it is possible to achieve a substantially flat gain response for a multi-wavelength output of the optical amplification apparatus. Some embodiments of the invention combine noise suppression and additional gain flattening on one or more wavelengths. Embodiments of the optical amplification apparatus can be used in red-band wavelength range applications of coarse wavelength division multiplexing (CWDM). Some embodiments of the invention also provide that the optical amplification apparatus can be used as a hybrid dense wavelength division multiplexing (DWDM) and CWDM optical amplifier.