Coherent Radar waveform Generation and IF signal detection using single laser source for Multi band Sensor Network Applications

The presence of multiband sensors boosts the capabilities of a sensor network in multiple folds. In this kind of applications, the coherency between the sensors is mandatory for real time data fusion. Photonics based solutions are capable of generating coherent multiband Radio Frequency (RF) signals and detecting its Intermediate frequency (IF) signals using a single hardware configuration. This is possible due to the wide bandwidth capability of photonic components up to mmwave range of frequencies. This helps in reducing the hardware complexity of sensor network architecture in comparison with RF counterparts with the generation of coherent multiband signals. This work brings out an architecture of a sensor network consisting of radars operating in different frequency bands. These radars generate transmit signals from an Intermediate Frequency signal and retrieve the signal back using a photonics based coherent radar transmitter-receiver. Heterodyning of various frequency modes of a single laser source along with a photo detector results in the generation of multiband RF signals. Conventionally this is achieved with different hardware for different frequency signal generation and detection using respective mixers with local oscillator signals. The usage of coherent transmitter-receiver block enables the data fusion of receive echo signals from multiband radar systems efficiently in comparison with conventional systems. In addition, the usage of fiber links allows to carry both transmit and receive signals for longer distance with less attenuation. The work is supported with modeling and experimental results of multiband RF signal generation, both carrier and chirped signals with its IF signal detection.