Problem with sensitivity in a laser distance measurement system

some one help me i am trying to design a laser distance measurement system, i am faced with a problem of sensitivity i am using IR led and photodiode, but i am not getting sharp signals for the receiver end. what should i do to better the receivng circuotry, should i use planoconvx lense in front end of receiver, fix a transimpedance amp or wattttttt? please help

Are you talking about a laser or an IR diode?

IR diode: pump it with short >1A pulses while keeping an 1 to 10%
duty cycle.

Laser diode: use TOF (time of flight) measurement method.
There are many distance sensors schemes on the net.