Photonic vector demodulation of 2.5 Gbit/s QAM modulated wireless signals

In this paper, a technique for demodulation of vector modulated signals like QAM, using photonic techniques is presented. The photonic vector demodulator is capable of converting broadband wireless QAM signals into independent inphase and quadrature optical baseband signals. Experimental demonstration of demodulation of 2.5 Gbit/s QAM modulated 20 GHz carrier is presented. Bit error ratio of the demodulated-I and -Q optical baseband signals is measured and an error free demodulation achieved. A receiver sensitivity of -26.5 dBm and -27 dBm were measured for the I and Q signals respectively.