Hybrid 2D–3D optical devices for integrated optics by direct laser writing

Abstract

Integrated optical chips have already been established for application in optical communication. They also offer interesting future perspectives for integrated quantum optics on a chip. At present, however, they are mostly fabricated using essentially planar fabrication approaches like electron-beam lithography or UV optical lithography. Many further design options would arise if one had complete fabrication freedom in regard to the third dimension normal to the chip without having to give up the virtues and the know-how of existing planar fabrication technologies. As a step in this direction, we here use three-dimensional dip-in direct-laser-writing optical lithography to fabricate three-dimensional polymeric functional devices on pre-fabricated planar optical chips containing Si 3 N 4 waveguides as well as grating couplers made by standard electron-beam lithography. The first example is a polymeric dielectric rectangular-shaped waveguide which is connected to Si 3 N 4 waveguides and that is adiabatically twisted along its axis to achieve geometrical rotation of linear polarization on the chip. The rotator's broadband performance at around 1550 nm wavelength is verified by polarization-dependent grating couplers. Such polarization rotation on the optical chip cannot easily be achieved by other means. The second example is a whispering-gallery-mode optical resonator connected to Si 3 N 4 waveguides on the chip via polymeric waveguides. By mechanically connecting the latter to the disk, we can control the coupling to the resonator and, at the same time, guarantee mechanical stability of the three-dimensional architecture on the chip.

Multi-criteria optimization in CO2 laser ablation of multimode polymer waveguides

“…For instance, it is noted by Yoon [28] that insertion loss of multimode polymer waveguide is significantly influenced by the sidewall roughness and the insertion loss decreases linearly as surface roughness improves. However, here the overall effect of surface roughness on the insertion loss of the fabricated waveguides was not investigated [29][30][31]. Moreover relevant experimental dataset pertaining to effect of sidewall roughness along with considered parameters was not available for GRA.…”

Vortex-MEMS filters for wavelength-selective orbital-angular-momentum beam generation

“…10 The SPP is fabricated utilizing direct laser writing of polymers (Photonic Professional GT with IP-Dip photoresist, nanoscribe GmbH, Germany) in dip-in configuration to enable integration directly on the surface of the finished MEMS device. First, the chip is fully covered by the liquid dip-in photoresist.…”

Employment of fluorescence for autofocusing in direct laser writing micro-/nano-lithography

“…This allows fundamentally unlimited integration and packaging of diverse functional microdevices. [42][43][44][45][46][47][48][49][50] It should be mentioned that such structures can serve as 3D templates for infiltration of another media with desired properties which cannot be nanofabricated in 3D by DLW. [51][52][53] Lastly, usage of ultrashort pulses enables avoidance of photosensitization [54][55][56] which is an arising issue and might be limiting factor to optical and biological applications due to its light absorption and toxicity.…”