I have to set up a connection from a BIDI SFP to a unidirectional SFP. Any idea how this i even possible? is there an intermediary device that can aggregate the Tx and Rx of one fibre and output only into one line?
Short answer: NO
The bidirectional (single wire) SFPs come in pairs because they use different frequencies in each direction. Even if you did split the fiber, the TX and RX wavelengths would (a) be different, and (b) not likely to conform to any standard SR/LR optics. You'll need some form of "media converter" (aka: two port switch) that can take the matching SFP and convert it to whatever standard you want.