Single-photon counting has found broad applications within quantum technologies, such as quantum sensing, quantum information, and quantum communication. Recently it was proposed that low jitter single-photon detectors could be used to realize optical random sampling scopes with a bandwidth well beyond 100 GHz, a range not accessible with existing measurement instrumentation. This technique is suitable to support research on mode-locked lasers and next-generation electro-optical devices such as EOMs and VCSELs. Moreover, the optical sampling technique does not require the transmission of extreme fast electric signals over metal wires, which introduce increasing signal distortions and attenuation for high bandwidth signals. In the Swabian Instruments application note, we showcase a proof-of-principle measurement and characterize commercial SFP+ modules using both Single-Photon Avalanche Detectors (SPADs) and Superconducting Nanowire Single-Photon Detectors (SNSPDs). With the jitter of current SNSPDs reaching a few picoseconds, the method promises a measurement bandwidth well beyond 100 GHz.
For more technical details, please take a look at our application note.