39 the ends of fibers 32 can be flush with the edge of connector block 51 this configuration protects the fiber ends from damage during production and assembly without the micro lenses the fiber ends would have to protrude beyond the edge of block 51 and extend through openings 38 this sort of solution is fragile problematic and therefore costly thus the optical properties of micro lenses 39 e g focal length working distance spot size are typically designed depending on the layout and mechanical tolerances of the module elements e g depending on the length of openings 38 i e the thickness of pcb 34 pcb 34 typically comprises circuit traces for carrying electrical signals between the optical transducers e g vcsels and or pds and other electronic components not shown the other components may be mounted on pcb 34 or elsewhere such components may comprise for example drivers that drive the vcsels with electrical signals to be converted to optical signals trans impedance amplifiers tias that amplify the electrical signals produced by the pds in response to received optical signals control circuitry or any other suitable components the use of pcb 34 in the configuration of fig1 and 2 enables very short electrical paths between the transducers and the additional components e g from the drivers to the vcsels and from the pds to the tias in one example embodiment these electrical paths have a length on the order of 0 7 mm which enables high.