Laser-beam lithography for large-area optical integrated circuits

There has recently been remarkable Interest in making an optical IC having the function of complicated optical signal processing by combining several guided-wave devices on a common substrate. Since each device is usually at least 5 mm, the total length of such an optical IC becomes >30 mm. Large- area waveguide patterning, therefore, is required. For this requirement, laser-beam lithography Is more suitable than existing photo-beam and electron-beam lithographies, as already pointed out by some researchers who used a simple experimental setup comprising manually controlled translation stages and appropriate focusing optics.1,2 We recently developed a computer-controlled laser-beam lithographic system to make large-area optical ICs.3 The laser-beam lithography for two different types of practical optical IC, used for velocity measurement, is demonstrated to discuss performance of the developed system.