Linear electro-optic effect applied to a radio astronomy correlator

Authors

  • N. Ross Price,

  • Philipp P. Kronberg,

  • Keigo Iizuka,

  • Alois P. Freundorfer


Abstract

Studies of weak millimeter-wave cosmic radio sources in the next generation of millimeter interferometers will, for optimal sensitivity to continuum radio sources, require continuum cross correlators with an input passband of approximately 10 GHz, in comparison to the 500 MHz devices presently installed. We have designed and tested an optoelectronic continuum correlator which can achieve such high bandwidths using integrated optic Mach-Zehnder interferometric modulators (to convert the IF signals from the radio telescope receivers to optical signals) and photoreceivers (to convert the optical signals back to electrical signals). A prototype real-channel continuum correlator of this type is described. It performs with an overall efficiency of 81 ± 3%, which compares favorably with typical electronic digital and analogue correlators currently used in radio astronomy.