AFE4404EVM: dealing with very low signal values

Hello,

I am currently working with a AFE4404 EVM - Kit. In my Application (both emitter and detector are butt-coupled to a fiber each and then imaged to a sample) i have to deal with very low signal values. I already use the highest Emitter current values and the highest possible Gain. In this Setup i am only able to achive 4% of FS at best.

Is there a way to integrate the LED signal over a longer period of time to get a higher ADC reading? Or is there another option (except changing the optics/fibers/emitter/detector-parts) to get a higher reading.

Regards

Alex