Patent ID: 8787412

Claim:
Method for calibrating and tuning a part wise monotonically, continuously tunable semiconductor laser ( 121 ; 10 ) comprising at least a phase section ( 12 ) and at least a first Bragg reflector section ( 14 a , 14 b ), through which sections a phase current and a first reflector current, respectively, are applied, said method comprising a) a calibration step, comprising firstly obtaining at least two tuning lines ( 301 ) along which tuning lines all combinations of phase and Bragg currents are stable operating points of the laser ( 121 ; 10 ), secondly identifying at least one reference stable operating point along at least a first one of the identified tuning lines ( 301 ) at which operating point the laser ( 121 ; 10 ) emits light at a certain reference frequency, and thirdly storing into a memory the at least one reference stable operating point; and b) a subsequent tuning step, during which the output frequency of the laser ( 121 ; 10 ) in relation to the said reference frequency is controlled to a desired output frequency by translating the operating point of the laser ( 121 ; 10 ) along the said first tuning line according to a known relationship between relative position along the tuning line and relative laser frequency shift, and, whenever said translation from the said reference operating point is or becomes too great for the operating point to fit along the first tuning line, continuing the translation along another one of the identified tuning lines ( 301 ) so as to achieve the desired output frequency.