The output of the operational amplifier is proportional to the incident light provided {TAIL ~ the intensity} on {HEAD ~ each photodiode} are proportional to each other 
The output of the operational amplifier is proportional to the incident light provided { TAIL ~ the intensity } on { HEAD ~ each photodiode } are proportional to each other
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH