Ciena Corporation

Robert Corwin

Steven W Cornelius

Stephen B Alexander

Donald J Miller

Cecil D Smith

Roy C Litz

Prasad Dasika

John H Brownlee

Donald T Newman

John L Shanton, Iii

Todd Appleton

A receiver node includes an optical amplifier optically coupled to the input of a receiving device such as a PIN photodiode. A controller inputs received power level values from the receiver to perform gain control. The input signal of an optical receiving device is pre-amplified by an optical amplifier such that the amplified signal is within a dynamic range of the receiving device. Upon the occurrence of a LOS (loss of signal) event, the controller sets the gain to a Home Gain value. Thus, when the signal is reestablished, a strong signal will not be over amplified and damage the receiver. Gain control is reestablished when the LOS event is over. Various methods are used to declare LOS including comparing the received power level or commanded pump power against a threshold. The LOS declaration may also be received from an external device or service channel.

Optical pre-amplifier apparatus and method for receiver performing gain control according to LOS declaration

An optical amplifier is added to the input of a photodetector to perform optical pre-amplification of an input optical signal before it is converted to an electrical signal by the photodetector. A controller utilizes a received power level to control a pump power level of a pump injecting pumping light into the optical amplifier. The pump power level is controlled in order to control the optical gain of the optical amplifier. The received power level may be measured by a receiving device that includes the photodetector and a power measuring device. The pump output power level may also be fed back to the controller to monitor the pump. A dual pass EDFA may be used as the optical amplifier and coupled to a selector to save space and reduce noise.

Gain controlled optically pre-amplified receiver apparatus and method

A receiver node includes an optical amplifier optically coupled to the input of a receiving device such as a PIN photodiode. A controller inputs received power level values from the receiver to perform gain control. The input signal of an optical receiving device is pre-amplified by an optical amplifier such that the amplified signal is within a dynamic range of the receiving device. Windows are utilized to trigger the gain control algorithm such that when the received power level is inside a first window the gain control is turned off. When the received power level is outside the second window, the gain control is turned on. Additional windows may be used to adjust the rate of gain change. The rate of gain change is decreased as the magnitude of the difference between the current received power level and the target received power level decreases. Pump power levels may be fed back to the controller such that a soft limit may be imposed on to limit he maximum pump power and thereby prevent receiver damage.

Optical pre-amplifier apparatus and method for receiver performing windowed and gain change rate control

The present invention provides a system and method for intelligently shutting down an optical energy source in a communication system having optical amplifiers upon detection of a system failure.

System and method for shutting off an optical energy source in a communication system having optical amplifiers

Growing community of inventors

Finksburg, MD, United States of America

Robert Corwin