This paper presents the modeling, design, fabrication, and characterization of ultra-low loss 3D optical waveguides integrated on a glass photonic substrate. A novel, single-step process was developed using moving mask lithography to fabricate a single mode optical waveguide with a built-in turning mirror capable of making 40° or 45° turns for vertical grating couplers or photodetectors, respectively. Planar alignment of the waveguide to fiber interfaces enable passive alignment, contributing to system cost reduction. An optical path with 1.1 dB loss from fiber to die was obtained from optical modeling, while the fabrication of single mode waveguides with built-in mirrors at <1° angular control was demonstrated.
High-Efficiency SOI Fiber-to-Chip Grating Couplers and Low-Loss Waveguides for the Short-Wave Infrared
