the following is intended as gently as possible
read the instructions and specifications of your DFB laser
do some research on how to produce the voltages/currents/power you need
do some research on the appropriate modulation methods
sketch out a circuit that may do the job
simulate the circuit
in short, put in some effort on your project, then ask questions
this forum is about answering questions, not providing turnkey solutions
you have to pay for those, but not here.