Patent ID: 6826203
Filing Date: 2004-11-30
Classification: H01S

Abstract:
A method of testing a distributed feedback (DFB) laser to determine whether a gain margin value of the DFB laser exceeds a minimum gain margin value, wherein said testing is based on a threshold current value measured in the DFB laser, the method comprising:determining a maximum threshold current value, said determining comprising: calculating a corresponding gain margin value and threshold current value for each of a plurality of DFB lasers; identifying, from among the plurality of DFS lasers, a subset of DFB lasers for which the corresponding calculated gain margin value is less than the minimum gain margin value; identifying, from among the calculated threshold current values of the subset of DFB lasers, a lowest calculated threshold current value; and setting the maximum threshold current value to the lowest calculated threshold current value; measuring a threshold current value of a DFB laser under test; and determining that a gain margin value of the DFB laser under test exceeds the minimum gain margin value when the measured threshold current value does not exceed the maximum threshold current value.