Statistical Characterization of High-Speed Oscilloscopes and Photodiodes

SED staff began a collaboration with the EEEL Optoelectronics Division staff in 1998 to develop statistical signal processing methods for analysis of time-domain optoelectronic response measurements. Optoelectronic devices are critical for high bandwidth measurements of high performance optical fiber systems. A photodiode converts an optical signal into an electrical signal. This electrical signal is detected with a high speed equivalent time sampling oscilloscope. Both the photodiode and oscilloscope have impulse response functions which distort the signal of interest.

As part of a interdisciplinary team including staff from the Optoelectronics and the Radio Frequency Technology Divisions of EEEL, SED staff are developing statistical methods and associated software for calibration of high-speed digital sampling oscilloscopes and characterizing the impulse response of photodiodes. Statistical tasks include:

• development of estimation methods and algorithms for timebase distortion estimation and correction,
• drift estimation,
• signal alignment, and
• timing jitter estimation.

Industries that will benefit from this work are involved in the following technologies: Gigabit Ethernet networks, Fibre Channel, CATV, satellite TV, tethered microwave antennaes, optical telecommunications, optical components and test equipment, SONET/SDH (synchronous optical network/synchronous digital hierarchy industry) and Wireless.

The following publications are related to this project.

Wang, C. M., Hale, P. D., and Coakley, K. J., "Least-squares estimation of time-base distortion of sampling oscilloscopes", IEEE Transactions on Instrumentation and Measurement, 48 (6), 1999, pp. 1324-1332.

Hale, P. D., Clement, T. S., Coakley, K. J., Wang, C. M., DeGroot, D. C., and Verdoni, A. P., "Estimating the magnitude and phase response of a 50 GHz sampling oscilloscope using the nose-to-nose method", Proceedings of the International Microwave Symposium Automatic RF Techniques Group, June 2000.

Coakley K.J. and Hale P. D., "Alignment of noisy signals", in revision for IEEE Transactions on Instrumentation and Measurement.

Hale, P. D. and Wang, C. M., "Heterodyne system at 850 nm for measuring photoreceiver frequency response", Proceedings of Optical Fiber Measurement Symposium, September 2000.

Clement, T. S., Hale, P. D., Coakley, K. J., and Wang, C. M., "Time-domain measurement of the frequency response of high-speed photoreceivers to 50 GHz", Proceedings of Optical Fiber Measurement Symposium, September 2000.

Wang, C. M., Hale, P. D., and Coakley, K. J., and Clement, T. S., "Uncertainty of oscilloscope timebase distortion estimate", submitted to IEEE Transactions on Instrumentation and Measurement.