Fiber photometry is a technique of growing popularity in neuroscience research. It is widely used to infer brain activity by recording calcium dynamics in genetically defined populations of neurons. Aside from the wide variety of calcium indicators, other genetically encoded biosensors have recently been engineered to measure membrane potential, neurotransmitter release, pH, or various cellular metabolites, such as ATP or cAMP. Due to the spectral characteristics of these tools, different assemblies of optical hardware are usually needed to reveal the full potential of various biosensors. In addition, combining multiple sensors in one experiment often requires investment in more complex equipment, which limits the flexibility of the experimental design. Such constraints often hamper a straightforward implementation of new molecular tools, evaluation of their performance in vivo, and construction of new experimental paradigms – especially if the financial budget is a limiting factor. Recently, we proposed a novel approach for fiber photometry recordings and optogenetic manipulation, Fused Fiber Photometry (FFP). Our approach offers remarkable flexibility in experimental design and facilitates the implication of new molecular tools in vivo at minimal cost. Here, we present a second-generation FFP system based on a novel fiber optic device, namely a wideband multimode circulator, with improved sensitivity that allows new experimental configurations.