Patent ID: 8861559

Claim:
A method to drive a semiconductor laser diode (LD) by supplying a bias current determined by an auto-power control (APC) loop and a modulation current Im calculated from the bias current based on a linear dependence of Im=α×Ib+β, the method comprising steps of: preparing a look-up-table (LUT) by procedures including, evaluating a plurality of sets of two parameters, (α, β) i (i=1 to n), at respective temperatures T i (i=1 to n), evaluating a first linear dependence of one of parameters, α i (i=1 to n), against temperatures to determine a slope and a y-intercept, a α and b α , of the first linear dependence, respectively and a second linear dependence of another of parameters, β i (i=1 to n), against temperatures to determine a slope and a y-intercept, a β and b β , of the second linear dependence, respectively, storing two slopes, a α and a β , and other two y-intercepts, b α and b β , in the LUT; sensing a current temperature T of the LD; calculating a set of parameters (α, β) T by referring to two slopes, a α and a β and two y-intercepts, b α and b β in the LUT, according to equations of: α T =a α ×T+b α , and β T =a β ×T+b β .