nanosecond electronic pulser circuit - up to 100MHz
Taking a risk on misunderstanding your load, I'd suggest the following



simulate this circuit &ndash; Schematic created using CircuitLab
If your output is a laser diode, then your drive to it should be a current source. You can use slower, higher current transistors in the output than your suggested BRF92, which is too weedy for your output, and too lively to be used as an emitter follower. Connected like this, you will get most of the advertised ft out of the transistors. Choose R1 with the supply voltage to set your load current.
The use of PECL (that is, ECL driven from +5 V instead of -5 V) in the pulse-forming stage has a number of advantages. It's about the right speed for your use. The LTC6752 is a bit slow for your suggested output pulse lengths. ECL is fairly tame when driven with delays like the RC shown. If you don't like the idea of a slow edge into the next gate, then as your delay is only a few nS, you could replace the RC with two or three feet of transmission line (with appropriate termination) to get the delay, RG178 is nice and thin, or a synthetic delay line from a few Ls and Cs. PECL has the right output voltage to directly drive the output current switch. Each positive going input edge will produce a positive going pulse.
U1 is some complementary ECL output gate, perhaps a TTL to PECL converter/level shifter.