ULTRAHIGH-RESOLUTION CHIRPED DISTRIBUTED-FEEDBACK GRATINGS FABRICATEDBY ELECTRON-BEAM LITHOGRAPHY USING BENT WAVE-GUIDES FOR LOW-COST PHOTONIC COMPONENTS

We present an efficient method to define arbitrarily chirped distribut ed feedback gratings giving differences between neighboring effective distributed feedback pitch lengths in the range of subinteratomic dist ances. Using bent waveguides superimposed on homogeneous distributed f eedback grating fields, distributed feedback gratings with arbitrary c hirping in the axial direction can be generated by appropriate bending functions. The bending functions are generated by high resolution ele ctron-beam lithography on a set of masks which can be frequently reuse d for a low-cost production process. We describe the design principles to enhance the device yield per wafer by defining specific unit cells which are reproduced as often as necessary to obtain full coverage of the wafer. The method can be applied to several crystalline, amorphou s, or polycrystalline solid-state materials such as inorganic or organ ic semiconductors, inorganic or organic dielectrics, glass, and polyme rs. Our method will be demonstrated for distributed feedback grating b ased photonic inorganic semiconductor devices. (C) 1995 American Vacuu m Society.