Novel Nanofabricated InP Photonic Integrated Circuits Devices

Indium Phosphide (InP) is a crucial semiconductor material for photonic integrated circuits (PICs), yet its nanoscale fabrication is challenging. We present several novel InP PIC devices with nanoscale fabrication achieved at JWNC, realizing sub-100 nm fabrication in laser gratings, asymmetric waveguides, and photonic crystals, demonstrating world-class InP fabrication technology.

InP Nanoscale Sidewall Grating (fig 1)

Achieving smooth and vertical gratings is essential for sidewall DFB lasers. We present a fabrication recipe for InP grating waveguides with a grating period of 240 nm and a ridge height of 1.92 μm, yielding an aspect ratio of 1:8. The sidewall grating structure is applicable in semiconductor lasers, microcavity filters, and slow-light effect devices. Tools: E-beam lithography, ICP etching, and HSQ resist.

Asymmetric InP waveguide (fig 2)

Asymmetric waveguides are effective for optical mode conversion. We present a polarization mode converter utilizing a step-stage asymmetric waveguide, achieving a 98% conversion efficiency from TE to TM polarization. The primary application of these asymmetric waveguides lies in polarization mode modulation in free-space optical communication. Tools: E-beam, ICP etching and HSQ resist.

Topological photonic crystal based on InP (fig 3)

Photonic crystals (PhCs) have wide applications in lasers, slow-light effects, and nonlinear optics. We developed a process for fabricating 100 nm-scale 1550 nm valley-topological photonic crystals on InP. PC hole sizes range from 80-150 nm, with hole gaps as small as 35 nm. These structures are applicable in photonic crystal lasers and topological PhC waveguides. Tools: E-beam lithography, ICP etching, and PECVD.

Photonic crystal on ridge waveguide (fig 4)

We combined a dense PC array on ridge waveguides with depths of 3.5 μm and 3.3 μm. The PC holes have a 90 nm diameter and a 1.92 μm depth, yielding an aspect ratio of 1:21. These structures are applicable in photonic filters and multiplexers, lasers, and biosensors. Tools: E-beam lithography, ICP Cobra etching, and PECVD.

+++