Platinum (Pt) thin film heaters are deposited by a focused ion beam for semiconductor manufacturing of thermally tunable distributed feedback lasers. An exemplar 1.3 .mu.m InGaAsP/InP laser is integrated with a tuning element having a wide wavelength tuning range of 4.9 nm, that is, 857 GHz, with a small heater current of 13.0 mA.