Optium Corporation

Lucent Technologies Inc.

At+t Corp.

Finisar Corporation

Uniphase Corporation

Stephen Bradley Krasulick

Thomas R Frederiksen, Jr

Thomas Francis Strelchun

Paul Kit Lai Yu

Terence D Grenda

Anthony J Wiencek

Christopher Robert Stook

Kenneth L Cockerham

Paul K Tallat-Kelpsa

Paul Yu

An integrated laser device includes a pre-distortion circuit. The pre-distortion circuit receives an electrical modulation signal and generates a pre-distorted modulation signal. A laser is integral with the pre-distortion circuit. The laser includes an electrical modulation input that is connected to the output of the pre-distortion circuit. The laser modulates an optical signal with the pre-distorted modulation signal. The pre-distorted modulation signal causes at least some vector cancellation of distortion signals generated when the laser modulates the optical signal.

Modulated laser with integral pre-distortion circuit

An optical transmitter and methods of generating an optical signal having SBS suppression are described. An optical transmitter having SBS suppression according to the present invention includes a signal generator that generates a SBS suppression signal. A laser generates a line width broadened optical signal having AM noise. A signal processor generates a modified SBS suppression signal from the SBS suppression signal. A modulator modulates the line width broadened optical signal having the AM noise with a payload modulation signal and with the modified SBS suppression signal to generate a payload modulated optical signal having SBS suppression and reduced AM noise.

Optical transmitter with SBS suppression

Apparatus and methods for linearizing an optical transmitter are described. A linearized optical transmitter according to the present invention includes a modulator bias voltage supply that biases an optical modulator. The optical modulator modulates an optical signal with a payload modulation signal. A feedback circuit receives electrical distortion signals generated by the modulator and generates a control signal in response to at least one of the electrical distortion signals. The control signal changes the bias voltage generated by the modulator bias voltage supply so as to reduce the at least one electrical distortion signal.

Linearized Optical Transmitter Using Feedback Control

An electra-absorption modulator and electra-absorption modulated laser are described that include a semiconductor layer having an electrically controllable absorption. The material composition of the semiconductor layer is chosen so that the semiconductor layer is substantially transparent to light propagating through the semiconductor layer when a substantially zero or a reverse bias voltage is applied across the semiconductor layer at operating temperatures of the electro-absorption modulator that are substantially greater than 25 degrees Celsius.

Electro-absorption modulated laser with high operating temperature tolerance

A predistortion arrangement is described for using an input signal to drive a nonlinear device having a drive input. Initially, first means sample a portion of the input signal. The sampled portion of the input signal is introduced to at least one predistortion path including a mixer responsive to the sampled portion of the input signal for producing at least second order intermodulation products of the input signal. The second order intermodulation products are conditioned. Combining means then combine the conditioned second order intermodulation products with the sampled input signal in a way which produces a predistorted drive signal compensated for second order distortion for use in driving the drive input of the nonlinear device. In one aspect, the sampling means and the combining means may be provided using resistive networks. The use of the resistive networks eliminates the need for directional couplers incorporating magnetic components. Accordingly, the predistortion arrangement including the mixer and the resistive networks may be provided in the form of an integrated circuit.

Predistortion arrangement using mixers in nonlinear electro-optical applications

In a test configuration for a pre-distortion board configured with an analog laser, a test operator adjusts the settings for one or more components (e.g., potentiometers) on the pre-distortion board, e.g., to optimize the linearity of the analog laser, relying on information contained in a graphical display presented on a computer monitor. In one embodiment, a signal generator generates electrical signals, the pre-distortion board distorts the electrical signals, the analog laser converts the distorted electrical signals into optical signals, an optical receiver converts the optical signals back into electrical signals, a band-pass filter filters the converted electrical signals, an RF spectrum analyzer generates amplitude vs. frequency data from the filtered electrical signals, and a computer generates the graphical display from the amplitude vs. frequency data, wherein the graphical display has a bar graph that graphically and textually indicates the current distortion level of the analog laser relative to a distortion requirement level and an extreme distortion level for the current test.

Pre-distortion tuning for analog lasers

A circuit housed in a semiconductor laser package for interfacing a semiconductor laser with an external laser drive source. The circuit having a transformer with primary and secondary windings for matching the impedance of the laser drive source and the semiconductor laser. The circuit further includes a tilt circuit for compensating the negative sloping effects of the transformer.

Growing community of inventors

Fogelsville, PA, United States of America

Stephen Bradley Krasulick