DFB laser array with first order gratings fabricated by X-ray lithography

X-ray lithography was used to fabricate a first-order grating with a lambda /4 phase shift for a DFB (distributed feedback) laser array. The grating fabrication process is shown. Pulsed operation results are shown for a ridge-type laser array, which was designed with 7.5-A wavelength variation from laser to laser and a spacing of 125 mu m.<>