| 摘要 |
A control ( 20 ) and a method of controlling a tunable laser having a gain section ( 4 ), a phase change section ( 5 ) and a segmented Bragg grating reflector section ( 6 ) comprising a series of grating units ( 9 - 17 ) each of a different pitch, and an electrode ( 9 a- 17 a) associated with each grating so that an electrical current is applicable to each individual grating. The control ( 20 ) includes a plurality of digitally controlled sources ( 31, 32 ) of electrical current which are each connected to switch means ( 33 or 35, 36 ) operable to independently connect each of said sources ( 31, 32 ) to a respective electrode (e.g. 11 a or 12 a) associated with a grating (e.g. 11 or 12 ) which is one of a subset of consecutive gratings (e.g. 11 & 12 ) selected from said series of grating units ( 9 - 17 ).
|
