In this paper, we demonstrate recent progress in graphene-based photonic waveguide devices such as polymer
waveguide polarizer, thermo-optic mode extinction modulator and plasmonic photodetector for graphene-based
photonic integrated circuits.
Micro- and nano-fabrication methods facilitate the use of nanostructures for the separation of collections of particles and nanobio-based optical and electrochemical sensing. We have presented an easy and simple nanopore size reduction method of a low-stressed silicon nitride (SiN ) membrane nanosieve (100×100 μm 2 ) using a nanoimprinting method based on a natural thermal reflow of the contact imprinting polymer, possibly maintaining compatibility with complementary metal-oxide semiconductor integrated circuit processes. The nanopore pattern size of this nanosieve membrane was precisely patterned by a nanoimprinting process using an electron beam patterned silicon master, to about 30-nm diameter. By employing mainly an electron beam resist reflow phenomena after a nanoimprinting process and anisotropic reactive ion etch, the etch holes’ size was fabricated to be the same with nanopatterns on the polymer. The contact imprinting master can be used continually for the generation of nanopore patterns simply and easily. It can endure harsh conditions like high temperature up to 800°C, and it is inert to many aggressive and strong chemicals. Also, this would be a low-cost, simple, and easy fabrication method for the precise and reliable size-reduction control of nanopores for mass production of nanobio sensors or chips.
The hybrid nanocontact printing(HnCP) method is a technology for manufacturing an ultra violet(UV) imprinted silicon substrate from a master and then printing by letting it get in contact with a substrate coated with a metal thin film. It comprises a step in which a master with a nano-pattern is prepared; a step in which the resist is applied to the surface of the silicon substrate; an imprinting step in which the master is let to get in contact with the resist surface, pressurized and then taken off; a step in which the imprinted silicone substrate is manufactured into a nanocontact stamp by curing the resist on the imprinted silicon substrate; a step of inking a self-assembled monolayer on the surface of the imprinted silicone substrate stamp; a step of transferring a printing pattern by letting the imprinted silicone substrate stamp get in contact with the substrate coated with a metal thin film; and a step of forming a desired pattern on the substrate by etching the metal thin film on the substrate to which the printing pattern has been transferred. In case the HnCP method, on which this study is conducted, is used, it enables the stamp manufacturing process to be shortened and optimized, because the nanoocontact printing process is conducted by using an imprinted silicon substrate stamp, and it has the advantage of making the stamp have a large area so that it is possible to produce it in a large quantity through a mass production process. Also, as a hard stamp is used, any error resulting from an ultra micro torsion and mismatching can be prevented in the multi-layering process, and since any deformation or defect is not brought about, the pattern's resolution can be enhanced so that it is possible to embody a pattern of 100nm.
Polymer waveguides have attracted a great deal of attention for their potential applications as optical components in optical communications, optical interconnections and optical sensors because they are easy to manufacture at a low temperature, and they have a low processing cost. Hot embossing is powerful and effective tools to produce a large volume of waveguides and structure high-precision micro/nano patterns of thin polymer films using a stamp for optical applications. In this work, fabrication techniques of hot embossed polymeric optical waveguides for parallel optical interconnection module, multi-channel variable optical attenuator and optical printed circuit boards are demonstrated. The single- and multi-mode waveguides are produced by core filling and UV curing processes. New approaches to fabricating single-mode polymeric waveguides with the high thermal stability in thermosetting polymers and two-dimensional multi-mode polymeric waveguides for high-density parallel optical interconnections as well as a simultaneous fabrication of single-mode polymeric waveguides with micro pedestals for passive fiber alignment are also reported.
The optical interconnection between fibers and optical waveguides has been the most important factor for low-cost packaging of multi-channel PLC-type optical devices. Recently, polymer based PLC-type optical devices have been considered as an alternative fabrication method and are particularly attractive because of their satisfactory light guiding characteristics and easy fabrication process. In this study, a novel micro-mechanical passive alignment method for multi-channel polymer PLC devices has been designed and fabricated using a hot embossing technique. The main design issue is simultaneous fabrication of micro channels for single-mode waveguides and micro-pedestals for passive alignment on a polymer PLC surface in one step by hot embossing. Since the hot embossing process uses wet-etched silicon mould for pedestals, and alignment pits on silicon optical bench (SiOB) are also wet-etched in KOH solution, optical alignment was achieved through the simple insertion of micro pedestals into the alignment pits on SiOB. The hot embossed waveguide and passive alignment pedestals have been shown an accuracy of ± 0.5 μm. The propagation loss of fabricated single-mode polymer PLC was 0.83 dB/cm at a wavelength of 1550 nm, and passively aligned polymer PLC device with an accurate SiOB showed an average 0.67 dB coupling loss.