Ultrafast optical signal measurement using optoelectronic techniques

A novel ultrafast optical signal measurement technique is proposed that uses a fast photodetector and electrooptic (EO) sampling. The technique can satisfy three requirements for the measurement: large bandwidth, high sensitivity, and polarization independence. The measurement systems are demonstrated using two kinds of EO sampling configurations. One system uses direct EO sampling. It affords a larger bandwidth. The system can discern 100-Gbit s^-1 return-to-zero (RZ) optical pulse-pattern signals with an on-off ratio of 22 dB. The other system uses a waveguide intensity modulator in EO sampling. It affords higher sesitivity and can measure an 80-Gbit s^-1 RZ optical eye diagram. It is theoretically expected that the sensitivity of our system is higher than that of the all-optical technique.