In this paper, we discuss the use of MicroPhotonic processors to control the optical power distribution in photonic signal processing structures, achieving adaptive photonic RF filtering with arbitrary transfer functions. A new MicroPhotonics-based photonic signal processing architecture is presented, in which fibre collimator arrays, Opto-VLSI processors, and a WDM combiner are integrated within an optical substrate to control the gains and weights of numerous active fibre Bragg grating cavities of different lengths. MicroPhotonic technology provides a cost-efficient and reliable means for controlling the gains and the input power of the Bragg cavities. Simulation results show that a reconfigured 64-cavity photonic filter structure can generate arbitrary transfer characteristics at RF frequencies.