All phase sensing systems will reach a point where the system, or sensor(s) within the system, will “overscale” or saturate. In systems that rely on a measurement of phase change, overscale will occur when the sampling rate (or bandwidth) of the phase sensing system is insufficient to keep up with the rate of phase change caused by the incoming signal.

High fidelity signal reconstruction The proprietary OASiS™ approach provides a unique solution to the overscale problem for phase sensing systems, allowing complete high-fidelity reconstruction of even very large amplitude signals while still utilising efficient, highly multiplexed, architectures. This is a key feature that enables the Fosar system to require only a small number of fibres and a comparatively small number of lasers for a large seabed seismic array. High dynamic range With OASiS, the Fosar system has an effective dynamic range of 180dB – 1,000 times greater than typical electrical systems – so can handle even the largest airgun arrays at close proximity to the sensor.