Suppression of fringe diffraction in localized holographic exposure for DFB laser arrays

A six-wavelength MQW DFB laser array emitting around 1.55 μm realized in a single holographic lithography is described. Fringe-free localized grating isolation is attained using a mask with a novel aperture-edge design. The first-order grating periods as well as the ridge locations can be varied in a large span. The high throughput of holographic lithography is extended to multiwavelength DFB arrays.