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nano amps to several amps VCSEL driver circuit

Hi,

I'm a graduate student in optical sciences. I encounter some problems in designing a VCSEL driver circuit. 

We need to design a VCSEL driver circuit to drive and modulate a VCSEL by the current. Modulation requirements are as follow:

1. Pulse current of which peak value is around 45 amps

2. Pulse train reptition rate is 1kHZ

3. Pulse duration is around 1 nanosecond. Duty cycle is super small 1ns/1ms. Rise and fall time is 1ns respectively.


We have a 10nA-1000nA (100 levels, 10nA step) current source right now. It can meet the requirements 2 and 3. But the amplitude is ultra low. 

So I was wondering if I can have a suitable amplifier to amplify this nano-amp to 45 amps? The difficulty is although the duty cycle is super small, the rise and fall time of each pulse is nanosecond scale. The amplifier should be fast enough. Also, our input current should be adjustable. For example, 10nA corresponds to 45A, 20nA corresponds to 46A, 30nA corresponds to 47A, etc.