Optical sensing sheets, based on Fibre Bragg Grating (FBG) sensing elements embedded in
siloxane (PDMS), are produced and tested. The device shows promise in pressure mapping and tactile applications, in fields such as robotics and rehabilitation. FBGs inscribed in highly-birefringent photonic crystal fibres,
reflecting two Bragg peaks, are used, and the potential to discriminate pressure and temperature is explored.
The prototypes were produced by moulding technology and PDMS was cured at room temperature. One sample
with FBGs embedded in the middle layer of a 2 mm thick PDMS sheet exhibited a linear pressure sensitivity
of about 2:6 pm/kPa over the range of 0 - 250 kPa. Another sample was proposed and tested for temperature
insensitive measurements, by realising local stress concentration at FBG sections of the embedded fibre.
To realize a high density matrix of pressure sensors, mainly electrical approaches are reported. The proposed highdensity
optical pressure sensor is based on a matrix of 2 stacked layers of crossing multimode waveguides. When
pressure is applied on a crossing point, the distance between the waveguides from the upper and lower layer will
decrease and power is transmitted between these waveguides. The sensor consists of polymer waveguides embedded in
polydimethylsiloxane (PDMS) which is a very flexible material. Therefore, it is ideally suited to be applied on irregular
or moving surfaces especially for applications which require covering small areas with high density pressure sensors.