I want to drive a 1550 nm laser diode, 5 mW output, <150 mA of current, at a modulation frequency of 1-2 MHz. The WLD3343 will do this fine, right? At 1 or 2 MHz mod, what modulation depth do you typically see with the WLD? The next step will be to go to a 10 MHz modulation frequency, will the WLD be OK? We want the best modulation depth we can get. Will we see 100% depth at 1 MHz, and do you have a feeling for the modulation depth we would get at 10 MHz?
The WLD will go to 2 MHz in constant current mode and will have a depth of modulation of 100% at 1 MHz or more. It starts to roll off once one gets past 1.8 MHz, it drops 5-10% at 2 MHz and holds there well with a 2 MHz square wave. It will perform slightly better with a sine wave. But 10 MHz will roll off significantly and probably will not be usable. The output signal rolls off to zero at about 6 to 7 MHz; depending on the amount of current needed, it might work up to this range.