Real-time detection of femtosecond optical pulse sequences via time-to-space conversion in the lightwave communications band

A spectral nonlinear optics time-to-space converter operating in the lightwave communications band is reported for the first time. We demonstrate serial-to-parallel conversion of short frames of femtosecond pulses, for the first time operating at a conversion efficiency level allowing direct electronic readout at a conversion rate of hundreds of megaframes/s in real time, without signal averaging and with good signal-to-noise ratio. The results demonstrate that applications such as real-time measurements of ultrafast optical data sequences and header recognition in ultrafast optical time-division-multiplexed (OTDM) packet networks are approaching feasibility. Moreover, we analyze tradeoffs between optical powers and data rates from a system perspective, which allows us to assess the challenges for scaling to parallel demultiplexing of bit-interleaved OTDM transmission systems.