Ciena Corporation

James E DeGrange, Jr

Sridhar Balakrishnan

Balakrishnan Sridhar

Michael George Taylor

Jun Bao

Clark Scrandis

A method of coordinating channel power information in a wavelength division multiplexed (WDM) optical communication system is disclosed. The method determines weighting values for each channel of the WDM signal based on channel launch powers. A source data object may used to transmit the channel weights and channel information from network elements having channel sources such as transmitters to downstream network elements. Block data objects may be used to identify channel blocks in the system and are also transmitted downstream. The source and block objects may be correlated to determine which channels are in-view at a particular point in the network and thereby determine which of the channel weights should be used as a basis for managing the network at that point. A WDM system is also disclosed which may actively control channel launch powers and feed the adjusted launch powers into the method of coordinating channel power information.

Method and system for coordinating and utilizing channel power information in an optical communications network

The invention includes a method for controlling amplifier output power in an optical communications network having channel add/drop capability. A first transmission parameter and a second transmission parameter are determined at a first amplifier. In an exemplary embodiment, the first transmission parameter is a composite express signal-to-noise ratio and the second transmission parameter is a composite signal-to-noise ratio. The total output power of a downstream amplifier is adjusted in response to the first transmission parameter and second transmission parameter. A system for implementing the method is also disclosed.

Method and system for controlling amplifier power in an optical communications network having add/drop capability

To improve a power balance of an optical add multiplexer, an add amplifier is optically coupled to an add path of an optical add module. A through loss associated with a signal passing through the add module, and an add loss associated with a signal travelling an add path of the add module are known or otherwise calibrated values. An input power measurement of the signal input to the add module is used in conjunction with the through loss, add loss, and number of added channels to determine an add path amplification value. The gain of the add amplifier is controlled according to add path amplification value so that the power level of added channel(s) substantially matches the power level of the WDM signal output from the add multiplexer. Furthermore, the gain profile of the add amplifier preferably matches a gain profile of a signal input to the add module. In this way, the power level and gain profile of the added channel(s) can be controlled to match the power level and gain profile of the signal passing through the add module. These same techniques may also be applied to an optical add/drop multiplexer that not dropping any channels but is adding at least one channel.

Power balanced optical add multiplexer and power balancing methods therefore

A three stage optical amplifier is disclosed having a substantially flat gain profile. The amplifier includes a variable optical attenuator coupled between second and third stages of the amplifier and a dispersion compensating element. The attenuation of the optical attenuator is adjusted in accordance with the loss across dispersion compensating element and the optical power input to the amplifier to thereby obtain a substantially flattened gain profile. An offset value can also be used to refine the variable optical attenuator control and minimize nonflatness. The first and second stages are preferably pumped to provide high gain and a low noise figure and the third stage is preferably pumped to provide a high optical conversion efficiency. In an additional example, received optical powers associated with each of the channels in a WDM system are monitored and the attenuators within each amplifier in the system are controlled so that the received powers are substantially equal.

Three-stage optical amplifier having flat spectral gain

To improve a power balance of an optical add/drop multiplexer, an add amplifier is optically coupled to an add path of an optical add/drop module. A through loss associated with a signal passing through the add/drop module, a drop loss associated with a signal travelling a drop path of the add/drop module, and an add loss associated with a signal travelling an add path of the add/drop module are known or otherwise calibrated values. A dropped channel power measurement is used in conjunction with the through loss, add loss, drop loss, number of dropped channels and number of added channels to determine an add path amplification value. The gain of the add amplifier is controlled according to add path amplification value so that the power level of the added channel(s) substantially matches the power level of the WDM signal output from the add/drop multiplexer. Furthermore, the gain profile of the add amplifier preferably matches a gain profile of a signal input to the add/drop module. In this way, the power level and gain profile of the added channel(s) can be controlled to match the power level and gain profile of the signal passing through the add/drop module.

Power balanced optical add/drop multiplexer and power balancing methods therefore

The invention includes a method for controlling amplifier output power in an optical communications network. A first transmission parameter is determined at a first amplifier. In an exemplary embodiment, the first transmission parameter is a composite express signal to noise ratio. The total output power of a downstream amplifier is adjusted in response to the first transmission parameter. A system for implementing the method is also disclosed.

Method and system for controlling amplifier power in an optical communications network

The invention includes a method for determining channel power in an optical communications network. The method includes determining at least one transmission parameter for a channel. Exemplary transmission parameters include transmission rate and transmission format. A number of channel units is determined in response to the transmission parameter. Channel power is then determined for the channel in response to the number of channel units. A system for implementing the method is also disclosed.

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Glen Burnie, MD, United States of America

James E DeGrange, Jr