A magneto-optical fibre transducer

A modified optical circulator with a combined permanent and tuneable electromagnet with a coupled RF Bluetooth receiver is used as a simple, low-cost magneto-optical transducer to couple generic sensor signal outputs into optical fibres. As proof of concept, a simple remote wireless smoke detector is interrogated through 2 km of optical fibre using this device. The threshold applied voltage needed in this demonstration is <i>V</i> = 0.35V and the measured response time <i>t</i> = 6 <i>&mu;</i>s.