Analog predistortion linearization for optical fiber communication links
AssigneeThe Regents of the University of California
InventorsJames F. Buckwalter, Navid Hosseinzadeh, Aditya Jain, Roger Helkey
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Abstract
A predistorter for an electro-optical converter includes a plurality of low noise RF amplifiers distributed along a transmission line that receive an RF input. Second order intermodulation injection (IM2) circuitry includes an inductively-degenerated frequency doubler to square and filter IM2 products of the RF input. A Mach-Zehnder Modulator (MZM) is used for electro-optical conversion. Feed forward circuitry injects IM2 to independently propagate RF intermodulation components with velocity matching to the MZM. At least one driver injects the RF input and RF intermodulation components into the MZM.
Claims15
A predistorter for an electro-optical converter, comprising:
- a plurality of low noise RF amplifiers distributed along a transmission line that receive an RF input;
- second order intermodulation injection (IM2) circuitry comprising an inductively-degenerated frequency doubler to square and filter IM2 products of the RF input;
- a Mach-Zehnder Modulator (MZM);
- and
- feed forward circuitry for injection of IM2 to independently propagate RF intermodulation components with velocity matching to the MZM;
- and at least one driver to inject the RF input and RF intermodulation components into the MZM.
A method for linearizing an electro-optical conversion, the method comprising steps of:
- receiving a radio frequency (RF) signal;
- distributing amplification along a single-ended transmission line, wherein a delay of the transmission line is matched to group velocity of light in a Mach-Zehnder Modulator (MZM), and
- generating second order intermodulation injection (IM2), independently propagating RF intermodulation components to with velocity matching with the MZM and injecting the RF signal and the RF intermodulation components into the MZM.
Dependencies are inferred from the claim text.