Externally-Modulated Electro-Optically Coupled Detector Architecture for Nuclear Physics Instrumentation

• Published in: IEEE transactions on nuclear science Vol. 61; no. 3; pp. 1333 - 1339
• Main Authors: Wenze Xi, McKisson, J. E., Weisenberger, Andrew G., Shukui Zhang, Zorn, Carl
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-06-2014; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Arrayed waveguide grating; Detectors; electro-optical coupling; external-modulation; lasers; magnetic field; multiplexing; nuclear physics instrumentation; Optical crosstalk; Optical modulation; Optical pulses; Optical waveguides; radiation; radiation detectors; Wavelength division multiplexing
• ISSN: 0018-9499; 1558-1578
• DOI: 10.1109/TNS.2014.2322519

A new laser-based externally-modulated electro-optically coupled detector (EOCD) architecture is being developed to enable high-density readout for radiation detectors with accurate analog radiation pulse shape and timing preservation. Unlike digital conversion before electro-optical modulation, the EOCD implements complete analog optical signal modulation and multiplexing in its detector front-end. The result is a compact, high performance detector readout that can be both radiation tolerant and immune to magnetic fields. In this work, the feasibility of EOCD was explored by constructing a two-wavelength laser-based externally-modulated EOCD, and testing analog pulse shape preservation and wavelength-division multiplexing (WDM) crosstalk. Comparisons were first made between the corresponding initial pulses and the electro-optically coupled analog pulses. This confirmed an excellent analog pulse preservation over ~ 29% of the modulator's switching voltage range. Optical spectrum analysis revealed less than -14 dB crosstalk with 1.2 nm WDM wavelength bandgap, and provided insight on experimental conditions that could lead to increased inter-wavelength crosstalk. Further discussions and previous research on the radiation tolerance and magnetic field immunity of the candidate materials were also given, and quantitative device testing is proposed in the future.