boost - Experiments to convert analog 10ns pulse to digital 10ns pulse

My objective :

converting laser pulses from photo diode ranging from 10nA - 100mA (60dB dynamic range of incident power) to digital format, for measuring pulse width exactly

pulse width 10ns and repeating at a rate of 20us

EDIT: Modifications: photo diode current ranging 100nA -10mA

My problem statement

what i tried is a conventional approach using a TIA and limiting excess current at TIA input and using 3 additional opamp stages as i have to see the 10nA as 50mV , so i can fix a threshold of 25mV , i can limit the excess current to avoid saturation of opamps,the problem is the more number of opamp stages, they came because of GBWP as i require atleast 120dB of gain at 100MHz(1/10ns), this is done(simulated model) and i was able to achieve calculation of pulse width, but i did not like this !

My Idea !

what i am thinking is to boost the 10nA current to atleast 1uA and any way current limiting is taken care now i can detect pulse at low gains itself ! and i can overcome the stability problems at high gain

am i thinking wrong ? is boosting such a low current is possible ? any way i should be ready keeping the fact that "this will boost my dark and noise current also " in mind

EDIT:

sorry that i have made some serious claims, may be due to underestimating the design problem

here below i have the schematic and results obtained,and the results were not at all up to the mark as expected in the comments

schematic:

10nA input perfectly output is preserved

1uA input

1mA input

my simulator shows me some noise analysis results which looked impressive, but i have to find out how they are calculated

noise analysis results

At the end the pulse width is not all maintained, my current implementaion failed due to saturation of opamp i believe, any how doors open for the comments and criticism