Optical transponder test for multi gigabit rate

Testing optical transponders for multi gigabit rate is demanding but to do so for production volumes requires novel approaches to high-speed data verification and processing is at the limits of instrument technology. Conventional sampling oscilloscopes are limited in such volume-production environment, and their ability to process data by virtue of digital signal processing DSP. Digital signal processing of sampled data is possible when the sampling rate is greater than twice the spectral content in the signal, this is not possible to perform for multi gigabit rate signals, based on the physical limitations of the today´s state of the art sampling technology that uses e.g., gallium arsenide semiconductor technology. In the vector sampling method developed here, the amplitude, phase, and history of each sample are used to reconstruct the original signal and enable digital processing of various parameters of the signal that include jitter, spectral characteristics, digital low pass filtering for specific bit rate, and other critical parameters that affect the quality of signal transmission and the error rate. The reconstructed waveform in continuous discrete time enables are then processed and enable the same measurement capabilities of high speed sampling scopes with the advantage of the higher bandwidth. Performance examples of various test functions of jitter and eye diagrams will be given for comparison with conventional techniques.