Detection of Fast Transient Events in a Noisy Background

Transient signals accompanied by a high noise level pose both basic and practical detection challenges. Disciplines that range from communication and astronomy to molecular physics face a very similar detection problem. When phenomena of interest are repetitive, different averaging techniques can be applied in order to elevate the signal above the detection threshold. In contrast, nonrepetitive signals, commonly occurring in communication and astronomy, cannot be processed using averaging techniques. With the advent of near-noiseless replication techniques, single-instance signal separation from noise has become possible. Here, we demonstrate that a single-instance signal can be mapped to 300 optical carrier frequencies and detected with low-bandwidth receivers to generate detection gains of 24 dB with respect to a single integrating receiver with the same bandwidth. The spectral-replicating receiver was used to detect a single-instance signal with power that was four times lower than the accompanying noise level.