A 1.5 mu m DFB laser array with a 1 AA channel spacing set by monolithically integrated heaters

A laser array of four DFB (distributed feedback) lasers with a wavelength spacing as small as 1 AA has been demonstrated. The wavelength spacing is coarsely set by the built-in grating periods and is fine-tuned by a heater array integrated with the laser array. A tuning range of 14 AA and a channel spacing of 1 AA have been achieved. It is shown that both thermal crosstalk and RF crosstalk can be very low. It is noted that the integrated thermally tuned DFB laser array will be very useful in optical frequency division multiplexing systems.<>