Infinera Corporation

Jeffrey Bostak

Ting-Kuang Chiang

Vincent G Dominic

Michael Timothy Kauffman

Parmijit Samra

James Edward Stewart

Alan C Nilsson

Vassili Kireev

Paul Nathan Freeman

Fu-Tai An

Huan-Shang Tsai

Xinghua Yang

A scaling apparatus and method for compensating nonlinearity due to the finite output impedance of current sources in current-steering digital-to-analog converters (DACs) are disclosed herein. In an example, a DAC may receive a digital input signal. The DAC may determine an output current weight for each of a plurality of unit cells, based on an output impedance of the unit cell. Further, the DAC may generate an analog output signal by applying the plurality of output current weights to the digital input signal. Then, the DAC may output the analog output signal. The analog output signal may be a high frequency analog output signal, which may be an optical high frequency analog output signal. In an example, a transfer curve of the analog output signal may be linear in terms of analog output signal voltage versus digital input code. The output current weights may include one or more polynomial terms.

Scaling apparatus and method for compensating nonlinearity due to the finite output impedance of current sources in current-steering digital-to-analog converters

Consistent with the present disclosure, clock-and-data recovery (CDR) circuitry and driver circuitry are provided on a chip that is separate from the driver circuitry, thereby reducing the amount of power consumed by the driver circuitry and simplifying system design. In one example, timing of the ERZ signals is controlled by a feedback loop that adjusts the phase of a data carrying signal relative to a clock signal, such that the phase has a desired value. Timing of the ERZ signals may thus be adjusted to minimize errors.

Electrical return-to-zero (ERZ) driver circuit

Embodiments of the present invention provide arrays of electrical circuits having one or more chirped elements or components for providing output signals to corresponding arrays of electro-optic devices. Certain embodiments of the present invention include a plurality of modulator driver circuits, each of the plurality of driver circuits configured to be substantially identical to each other and provide a corresponding one of a plurality of modulator drive signals to a respective one of a plurality of electro-optic modulators, each of the plurality of modulator driver circuits being chirped to provide a desired output to the corresponding electro-optic modulator for enhanced operation. Each of the plurality of modulator driver circuits comprises a plurality of electrical components, at least one of the electrical components being chirped such that a design or operating parameter of the electrical component differs from an electrical component having a similar function in at least one of the remaining modulator driver circuits of the plurality of driver circuit. In certain embodiments, each of the plurality of modulator driver circuits is provided on a common substrate.

Modulator driver circuit having chirped components

A modulator drive circuit provides a modulator drive signal to modulate an optical signal for transport across a network infrastructure. The modulator drive circuit powered by an adjustable voltage source, such that the modulator drive signal is generated from a data signal and the adjustable voltage source, an AC component of the modulator drive signal being derived from the data signal while a DC component of the modulator drive signal being derived from the adjustable voltage source. An array of such modulator drive circuits are provided on a single substrate.

Optical modulator drive circuit with integrated low power output bias voltage control

An optical modulator drive circuit provides a different approach to driving an optical modulator than presently employed, resulting in a reduction in power dissipation of the drive circuit by as much as 80%. Therefore, this invention dissipates as little as 20% of power of the present drive circuits known in the art. The optical modulator may be a semiconductor electro-absorption modulator but the principle of the invention can be applied any other type of electro-optic modulator that relies on a voltage to modulate an optical signal.

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San Martin, CA, United States of America

Jeffrey Bostak