The Boeing Company

Thomas R Cooper

Daniel Yap

Robert R Hayes

Susan E Bach

Joshua A Conway

Remy O Hiramoto

Suzanne E Kubasek

Alan R Kost

Timothy J Gallagher

A system for equalizing amplitude tilt distortion in a signal includes an amplitude tilt maker and an amplitude tilt sensor. The input signal is split in the amplitude tilt maker between a signal through path and a phase shifted, time delayed signal path. The phase shifted, time delayed signal then passes through a voltage controlled attenuator. Combining the phase shifted, time delayed signal with the signal that travels along the signal through path provides the amplitude tilt. The tilt can be adjusted by changing the control voltage to the attenuator in order to compensate for amplitude tilt distortion in the input signal. The voltage controlled attenuator is controlled by the amplitude tilt sensor, which 'senses' the tilt using a loop signal from the amplitude tilt maker.

Dynamic amplitude tilt equalizer

A digitally controllable nonlinear pre-equalizer system receiving an input signal and generating an output signal, the system including a splitter for dividing the input signal into a first signal path and a second signal path, an attenuator and a time delay element in the first signal path, the attenuator and the time delay element operable to generate a linear signal, a mixer and a vector modulator in the second signal path, the mixer being responsive to a signal from a digital to analog converter coupled to a processor chip providing a digital signal to the digital to analog converter, the mixer and vector modulator operable to generate a nonlinear signal, and a summer for summing the linear signal and the nonlinear signal to generate the output signal.

Digitally controllable nonlinear pre-equalizer

A low voltage optical phase modulator includes a splitter having an input, a first output, and a second output. The input receives an optical signal and is split between the first and second outputs. A phase adjustment element is coupled to the second output and produces a predetermined optical shift in the optical signal to produce a phase-shifted optical signal. A first electroabsorptive element is coupled to the first output and blocks transmission of the optical signal when the first electroabsorptive element is activated with a low voltage. A second electroabsorptive element is coupled to the phase adjustment element and blocks transmission of the phase-shifted optical signal when the second electroabsorptive element is activated using the low voltage. An optical combiner having a first combiner input, a second combiner input, and a combiner output is coupled to the first and second electroabsorptive elements and receives the optical signal and the phase-shifted optical signal. The combiner combines these optical signals to produce a binary encoded optical signal. The present invention thus achieves an improved low voltage optical phase modulator. The present invention is advantageous in that substantially larger than 180 degrees phase shift can be achieved with the same low voltage by using optical paths having longer lengths.

Low voltage, optical phase modulator

A high power optical combiner ( ) is provided for amplifying an optical signal. The combiner ( ) includes a splitter ( ) having a splitter input ( )and two splitter outputs ( ). The splitter input ( ) receives an optical signal which the splitter divides ( ) into two sub-signals. The splitter outputs ( ) have respectively coupled thereto a reference arm ( ) and a dither arm ( ). Both arms ( ) receive the sub-signals from the respective splitter outputs ( ) and transmit the sub-signals in parallel. Each arm ( ) has an amplifier ( ) integrated therein for amplifying the sub-signals in parallel thereby producing amplified sub-signals. The high power optical combiner ( ) further includes a combining coupler ( ) connected to both arms ( ). The combining coupler ( ) has two coupler inputs ( ), and a coupler output ( ). The coupler inputs ( ) receive the amplified sub-signals from the arms ( ). The combining coupler ( ) constructively combines the amplified sub-signals to produce a primary amplified signal that is transmitted through the coupler output ( ). The coupler output ( ) has a dither tap coupler ( ) attached thereto for drawing a secondary amplified signal from the primary amplified signal. The secondary amplified signal is coupled to a phase controller ( ) and a polarization controller ( ), both of which are coupled to the dither arm ( ) between the splitter ( ) and the amplifier ( ). These controllers ( ) respectively adjust the phase and the polarization of the sub-signal in the dither arm ( ) to allow for efficient combination of the amplified sub-signals.

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Torrance, CA, United States of America

Thomas R Cooper