Corning Incorporated

Avanex Corporation

Kevin S Gerrish

Muhidin A Lelic

Aravanan Gurusami

David R Peters

Scott T Hilbert

A synthesized digital filter and method for synthesizing the digital filter are described herein. In one embodiment of the present invention, the digital filter is made using analog RF components. In another embodiment of the present invention, the digital filter is made using optical components which enables an optical signal to be manipulated in an optical domain without needing to convert the optical signal into an electrical domain.

Synthesized high speed digital filters

An amplifier characterized by gain and output power comprises: (i) at least one gain medium; (ii) at least one pump supplying optical power into the gain medium; and (iii) a controller controlling the gain and the output power of the amplifier. The controller includes a signal compression circuit to cover a wide dynamic range for optical input and output signals, so that resolution for low optical signals is better than resolution for high optical signals.

Universal controller for an optical amplifier that operates over a wide dynamic range of optical signals and optical amplifiers utilizing such controllers

A monitoring system useful for monitoring the state of a fiber communication channel in which a portion of the fiber signal is tapped and detected by a photodiode. The dark current of the photodiode and other DC offsets of the system may be compensated by passing a known signal through the photodiode and extracting the component due to the known signal. The known signal may be a locally generated optical signal having a predetermined harmonic signature. Optionally, the fiber signal may be selectively attenuated before being combined with the known signal so only the known signal is detected. The known signal may also be a dark signal induced by selectively attenuating the fiber signal. The system may include a temperature sensor which allows the compensation to be performed against stored temperature dependent compensation values while the fiber signal is not attenuated.

Automatic dark current compensation

A method for compensating for ASE in gain control mode while controlling gain of an optical amplifier, the method including the following steps: (i) obtaining value for input and output power electronic circuitry DC offset; (ii) selecting the following set point values: power set point&equals;0.0, gain set point&equals;desired gain, (iii) obtaining digital value representing signal input value and subtracting input power electronic circuitry DC offset to produce adjusted input power value; (iv) obtaining digital value representing signal output value and subtracting output power electronic circuitry DC offset to produce adjusted output power value; (v) obtaining the ASE content of the adjusted input power value by either utilizing a lookup table or a formula and subtract ASE content from the adjusted input power value to produce ASE adjusted output power value; (vi) either multiplying the gain setpoint by the obtained ASE adjusted input power value and subtracting this from the ASE adjusted output power value, or dividing the ASE adjusted input power to obtain gain control error signal; (vii) subtracting the gain control error signal from any number to produce a controller input signal; (viii) transforming the controller input signal into digital representation of at least one pump control signal by a control algorithm; (xi) transforming said digital representation of said at least one pump control signal into at least one corresponding analog pump control signal; and (x) applying the at least one analog pump control signal to at least one pump via driver circuitry.

Method for controlling performance of optical amplifiers

An optical fiber amplifier includes an optical system and an electronic controller. The optical system includes: an optical gain medium; at least one pump source coupled to the optical gain medium; an input port for in-coming signal; and an output port for an out-going signal. It also includes an input optical signal tap coupled to a first optical detector; and an output optical signal tap coupled to a second optical detector. The electronic controller is adapted to utilize inputs received from the tabs to control optical power provided by the pump source. The controller includes a user interface that allows a user to control at least one of the following available functions: desired amplifier gain value; amplifier output power value; ASE noise compensation.

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Elmira, NY, United States of America

Kevin S Gerrish