Ultra simple low-power RF signal detection based on an optoelectronic feedback DFB laser

An ultra simple and low cost method to detect low-power RF signal is proposed and experimentally demonstrated based on optoelectronic feedback DFB semiconductor laser. To our knowledge, according to public reports, this is the simplest photonics-assisted method which avoids using high sensitive optical modulators and narrow bandwidth optical filters. The RF signal, which matches the oscillation mode at the relaxation oscillation peak of the DFB laser, is amplified based on optoelectronic feedback. The RF signal from 1 to 4.5 GHz can be detected by adjusting the frequency of relaxation oscillation which is related to the laser bias current. The system provides a maximum gain of 15 dB for the low-power RF signal. The sensitivity of the system can reach up to as high as -97 dBm. Considering the real application of the detection system, the properties like dynamic range, resistance to large signals and performance for detecting modulated RF signal are also investigated.