Optical Modulation Analyzers
With bandwidth demand growing exponentially worldwide, the transmission rates of optical networks are increasing to 40 Gbit/s and, in the near future, to 100 Gbit/s. Thanks to advanced modulation schemes, ultra-high network speeds can be achieved using existing DWDM channel spacing, while maintaining resilience to chromatic and polarization dispersion phenomena. Full characterization of this ultra-high-speed encoding represents a significant challenge. This is where EXFO’s PSO-200 comes in.
Based on a unique optical sampling approach, the PSO-200 Optical Modulation Analyzer eliminates almost all the limitations typically found in electrical sampling oscilloscopes. To do so, narrow sampling pulses open a sampling gate that generates a time-stretched version of the measured signal. The optical samples are then converted to electrical signals, which can be easily detected by low-speed electronics and digitally processed.
Data coding in multilevel phase and amplitude formats increases the total capacity of optical transmission systems. Aside from the traditional on-off keying (OOK) format, differential phase-shift keying (DPSK) and differential quadrature phase-shift keying (DQPSK) with direct detection are the most frequently used formats, which leads to an increasing demand for intensity and, most importantly, optical-phase measurement techniques. One of the best ways to do so is through a sampling system displaying phase constellation diagrams that are not constrained to single pulses or short data patterns.