The model 280 photodiode test system introduced by dBm Optics Inc. enables PIN and avalanche photodiode suppliers to characterize the parametric performance of their components in R&D, quality assurance and production. Measurement noise of <200 fA results in accurate dark current characterization. Complete characterization of a photodiode, including responsivity and polarization dependency over a wavelength, is performed in <8 s. Real-time referencing eliminates traditional errors in responsivity measurement. The system can test one photodiode or hundreds in one system. The company says that it is accurate, fast and inexpensive.