Research On Gratings Preparation Of 2μm Antimonide Distributed Feedback Laser Diode

In the wave band of 2~5μm, there are two particular “ antmospheric window ”, which located in 2~2.5μm and 3.5 ~5μm. Laser in those two particular band possess the property of lower scattering and absorbability, which make it’s application prospect in areas like Spatial point to point communication, ladar or the indication of military targey quiet promising. Due to the grant development in fiber communications, seminconducter lazar( with tinner linning borad) has become major device in high-speed, long-distance communications and coherent communication, which makes DFB-LD become primary light source. Since antimonide semiconductor laser’s maser wavelength can be adjustable between 1.7 μm~4.5μm, antimonide marterial has become the first choice in crafting the mid infrared semiconductor lasers.So this paper focus on theoretically anaylsis of 2μm antimonide DFB-LD and the design aim to better laser structure. Which let to finer design in cycle, series, depth and duty cycle of the built-in Bragg grating and then the analytical experiment of the macheanism of both the antimonide dry etching and wet etching finally dry etch the 2μm DFB-LD built-in Bragg grating though holographic lithographically.With built-in Bragg grating rating 2, rating cycle 528 nm, duty cycle 0.25, depth 109 nm, the 2μm DFB-LD shows uniformity and close to rectangular grating. And though testing grating’s cycle, depth, duty cycle and surface topography by SEM and AFM, the graphic shows a ideal sinusoid with perfect surface topography, favourable continuity and uniformity, which means the grating built meets the need of second epitaxial growth and as such holds grave importance in building DFB semiconductor laser.