Consideration of direct bit‐rate measuring method based on extracting envelope signal

Abstract

SUMMARYWe previously developed an optical sampling oscilloscope (EDT-OSO) based on an envelope detection triggering method. This EDT-OSO can stably measure eye-diagram waveforms of signals exceeding 100 Gbps without an external high-frequency clock signal. However, far-end waveform measurements over a long distance could not be performed because the EDT-OSO requires the linkage of 10-MHz time bases in the EDT-OSO and a light under test (LUT) generator for synchronizing. To overcome this drawback we developed a direct bit-rate measuring method for synchronizing both 10-MHz time bases virtually and a self-synchronized EDT-OSO (SSEDT-OSO) based on this method. We confirmed that the bit-rate measurement repeatability of the SSEDT-OSO was from 10 -9 to 10 -8 by evaluating the standard deviation, and showed that the SSEDT-OSO can measure an eye diagram without linking to 10-MHz time bases. This paper explains the basic principle for measuring the bit-rate of the LUT directly. We also describe the configuration of the SSEDT-OSO and present evaluation results.