Laser rapid prototyping of photonic integrated circuits

Abstract

In this paper, we will describe our work at Columbia in developing a laser prototyping system, in conjunction with computer simulation, to design, fabricate, and test novel waveguide circuits. The system is also useful for manufacturing small-run circuit designs. The fundamental technique uses a laser-induced photoelectrochemical process for etching GaAs and other III-V compounds. The technique is maskless and discretionary. The computer-controlled apparatus can be programmed with any desired circuit pattern, and prototype waveguide circuits can be produced within a day. The waveguides and passive components produced with this technique include linear waveguides, tapered waveguides, abrupt and smoothly curved bends, Y-branches, asymmetric splitters, directional couplers, and optical delay lines. The passive devices are single-mode and low-loss. The technique also has the ability to vary the effective index of refraction along the device by grading the etch depth. In addition to passive devices, we have recently shown that active switching components can be prototyped by combining passive structures with laser-patterned metal electrodes. These electrodes are produced masklessly using standard metal deposition techniques coupled with laser- patterning of photoresist. In addition, metal can be deposited directly using laser-induced selective metallorgainic CVD.