Broadband Feedforward Photonic Linearization Circuit for High Dynamic Range RF Links

Pharad is teaming with the Applied Physics Laboratory of The Johns Hopkins University to propose and investigate the feasibility of a novel, broadband photonic linearization circuit based on a feedforward technique for airborne military communication platforms. The circuit will have the ability to achieve all-order distortion and noise suppression and be suitable for both directly and externally modulated laser diode analog optical links. The proposed architecture is inherently broadband to allow wide instantaneous bandwidth and/or multi-spectral signals with a target bandwidth of sub-100 MHz to 20 GHz. It also offers the capability to be real-time adaptable to retain maximum effectiveness in response to the presence of dynamic input signals and drift due to environmental effects. The photonic circuit could be easily implemented in a wavelength division multiplexed (WDM) network, with each WDM transmitter module containing identical photonic linearization circuits with software selectable control to optimize the particular RF signal(s) carried on the WDM channel. We will both model and experimentally demonstrate an implementation of the feedforward linearization architecture using COTS components in order to complete a feasibility study for meeting the performance requirements. Our investigation will include an analysis of suitable operating parameters where our broadband feedforward architecture will excel.