Abstract: In embodiments, an apparatus to predict failure of a laser is presented. The apparatus may include a memory to store a reference model of bias current change for a laser as a function of time and temperature, one or more sensors to detect: temperature, elapsed operating time and bias current of the laser, and a processor communicatively coupled to the memory and to the one or more sensors. The processor may be to calculate an actual bias current change ?IA at a current laser temperature, and an expected bias current change ?IE, based at least in part on the reference model and an average operating temperature, subtract ?IE from ?IA, and if the difference is greater than a pre-defined value ?, output a signal. Related methods and non-transitory computer-readable media may also be presented.

Abstract: In embodiments, an apparatus to predict failure of a laser is presented. The apparatus may include a memory to store a reference model of bias current change for a laser as a function of time and temperature, one or more sensors to detect: temperature, elapsed operating time and bias current of the laser, and a processor communicatively coupled to the memory and to the one or more sensors. The processor may be to calculate an actual bias current change ?IA at a current laser temperature, and an expected bias current change ?IE, based at least in part on the reference model and an average operating temperature, subtract ?IE from ?IA, and if the difference is greater than a pre-defined value a, output a signal. Related methods and non-transitory computer-readable media may also be presented.

Abstract: Adaptive power setting techniques for optical transceivers are provided. Optical signals are received at a first optical transceiver device that are transmitted from a second optical transceiver device. A receive power of the optical signals received at the first optical transceiver device from the second optical transceiver device is determined. A characteristic of optical signals transmitted by the first optical transceiver device to the second optical transceiver device is modulated to indicate to the second optical transceiver device a disparity of the receive power with respect to a target receive power level at the first optical transceiver device. Conversely, the first optical transceiver device adjusts a power level of optical signals transmitted by the first optical transceiver device to the second optical transceiver device based on a characteristic of the optical signals received at the first optical transceiver device.

Abstract: Adaptive power setting techniques for optical transceivers are provided. Optical signals are received at a first optical transceiver device that are transmitted from a second optical transceiver device. A receive power of the optical signals received at the first optical transceiver device from the second optical transceiver device is determined. A characteristic of optical signals transmitted by the first optical transceiver device to the second optical transceiver device is modulated to indicate to the second optical transceiver device a disparity of the receive power with respect to a target receive power level at the first optical transceiver device. Conversely, the first optical transceiver device adjusts a power level of optical signals transmitted by the first optical transceiver device to the second optical transceiver device based on a characteristic of the optical signals received at the first optical transceiver device.

Abstract: A repeater node for an optical transmission system provides amplification of optical signals and uses a modulated pump signal to transfer status information about the repeater node to a control system via an optical supervisory signal. The pump signal supplied by a pump source to an optical amplifier is modulated with one or more tones that are indicative of status in the repeater node. In a transmission fiber coupled to the output of the optical amplifier, the modulation of the pump signal is transferred to the supervisory signal of the optical transmission system as a result of Raman effect. More specifically, the pump wavelength and the supervisory signal wavelength are such that the modulated tone on the shorter wavelength pump signal is transferred to the longer wavelength supervisory signal. The tone can then be extracted from the supervisory signal and processed at another node in the system.

Abstract: A method and apparatus for controlling transients in an optical signal propagating along an optical fiber path interconnecting a plurality of network elements employs a power threshold to determine an appropriate response given a change in optical signal power.

Abstract: A method, apparatus and system for reducing gain ripple in a Raman-amplified WDM system includes determining a gain profile of an optical signal transported via a first Raman amplification span in a Raman-amplified WDM system, comparing the determined gain profile to a gain profile of an optical signal transported via a second Raman amplification span, determining, from the comparison, an amount of wavelength adjustment required for a plurality of Raman pumps comprising at least one Raman pump block of the second Raman amplification span to alter the gain profile of an optical signal transported via the second Raman amplification span, such that a cumulative gain profile of an optical signal transported via the first and the second Raman amplification spans approaches a desired gain profile, and generating a control signal suitable for adjusting the wavelengths of the plurality of Raman pumps of the at least one Raman pump block an amount consistent with the determined amount.

Abstract: A repeater node for an optical transmission system provides amplification of optical signals and uses a modulated pump signal to transfer status information about the repeater node to a control system via an optical supervisory signal. The pump signal supplied by a pump source to an optical amplifier is modulated with one or more tones that are indicative of status in the repeater node. In a transmission fiber coupled to the output of the optical amplifier, the modulation of the pump signal is transferred to the supervisory signal of the optical transmission system as a result of Raman effect. More specifically, the pump wavelength and the supervisory signal wavelength are such that the modulated tone on the shorter wavelength pump signal is transferred to the longer wavelength supervisory signal.

Abstract: A method and apparatus for controlling transients in an optical signal propagating along an optical fiber path interconnecting a plurality of network elements employs a power threshold to determine an appropriate response given a change in optical signal power.

Abstract: A method and apparatus for controlling transients in an optical signal propagating along an optical fiber path interconnecting a plurality of network elements employs a power threshold to determine an appropriate response given a change in optical signal power.

Abstract: A method, apparatus and system for reducing gain ripple in a Raman-amplified WDM system includes determining a gain profile of an optical signal transported via a first Raman amplification span in a Raman-amplified WDM system, comparing the determined gain profile to a gain profile of an optical signal transported via a second Raman amplification span, determining, from the comparison, an amount of wavelength adjustment required for a plurality of Raman pumps comprising at least one Raman pump block of the second Raman amplification span to alter the gain profile of an optical signal transported via the second Raman amplification span, such that a cumulative gain profile of an optical signal transported via the first and the second Raman amplification spans approaches a desired gain profile, and generating a control signal suitable for adjusting the wavelengths of the plurality of Raman pumps of the at least one Raman pump block an amount consistent with the determined amount.

Abstract: A method and apparatus for controlling transients in an optical signal propagating along an optical fiber path interconnecting a plurality of network elements employs a power threshold to determine an appropriate response given a change in optical signal power.

Abstract: A high efficiency, low noise, variable gain and low cost amplifier for use in an optical communication system uses a common pumping scheme for simultaneous Raman and erbium amplification in a single module. The invention can be used with any type of fiber which is doped with Erbium and used as a medium for achieving signal amplification due to simultaneous Raman and erbium amplification mechanisms. It can also be extended to any combination of any type of fiber and an erbium doped fiber, where the combination is used to achieve signal amplification due to simultaneous utilization of Raman and erbium amplification mechanisms.