Photonic Analog-to-Digital Converter for High-Speed Optical Processing

Technology #16055

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Researchers
Henry Zmuda
Nickolas P. DiRocco
Managed By
Richard Croley
Assistant Director 352-392-8929

High-Bandwidth, High-Resolution to Operate at Speeds That Outperform Commercial Electronic Converters

This high-bandwidth device uses photonic processing to implement a high-speed, high-resolution analog-to-digital converter. An analog-to-digital converter converts an analog voltage level into an n-bit binary word. In an all-digital era, the trend is to replace all conventional analog electronic systems with digital processors. However, the ability to obtain a high level of resolution for large bandwidth systems is presently limited by the conversion speed and resolution, or effective number of bits, of the analog-to-digital converter. To overcome these limitations of analog-to-digital converter systems performance, existing technologies use complicated subsystems. Researchers at the University of Florida have developed a photonic analog-to-digital converter with the potential to operate at speeds significantly faster than existing photonic or electronic ADCs while still upholding a simple design. The device is readily amenable for implementation as a silicon-based, photonic integrate circuit for electronic devices; it could serve as the basis for software-defined radio, digital communication and control for microwave systems, and more efficient digital measuring equipment. Additionally, this architecture can be employed in digital signal processing systems.

Application

High-speed, high-resolution, photonic-based analog-to-digital converter for improved optical and digital processing

Advantages

  • Feedforward technology retains high-resolution of signal, increasing efficiency levels in analog-to-digital converter performance
  • Simplistic photonic base decreases analog-to-digital converter volume, improving converter compatibility and versatility
  • High bandwidth analog-to-digital converter system improves speed and structure of existing ADC technology, enhancing marketability while reducing manufacturing cost

Technology

This analog-to-digital converter system employs an optical modulator to alter the state of polarization of a single light source. The approach used here uses one high-speed modulator driven by the signal to be digitized to avoid the problem of distributing exact replicas of the digitized signal to multiple modulators. Standard optical components then determine the state of polarization and generate a binary word that represents the amplitude of the analog voltage level. High speed is achieved by taking advantage of the fundamental property of a Pockels Cell to control linear wave polarization using the electro-optic effect. In a further aspect, once a bit is determined, its state is fed forward to the next least significant bit to aid in determination of the next lower bit. This nonlinear feedforward aspect of the analog-to-digital converter provides simplicity of its architecture.