Fabrication of digital planar holograms into high refractive index waveguide core for spectroscopy-on-chip applications

Abstract

Fabrication and optical measurements of germanium-doped silica ridge waveguides using a colloidal suspension approach Appl. Phys. Lett. 87, 121114 (2005); 10.1063/1.2037863Plasma silicon oxide-silica xerogel based planar optical waveguides A novel class of large-bandwidth wavelength demultiplexers, based on digital planar holography for on-chip spectroscopy applications, was fabricated in high refractive index contrast SiO 2 /Si 3 N 4 planar waveguides. The devices consist of computer-generated digital planar holograms (DPHs) encoding the transfer function of the demultiplexers, engraved on the core layer of the optical waveguide. An optimized fabrication process has been developed to produce DPHs with an etching depth as low as 10 nm in Si 3 N 4 . The first spectrometer devices exhibit overall bandwidths as large as 98 nm and spectral channel spacings down to 0.3 nm/channel.

Holographic planar lightwave circuit for on-chip spectroscopy

“…27. A micro-objective system is used to project the demagnified image of the output fiber from the light source to the input of the DPH chip.…”

“…39 After the lithography step, the chip is covered with a 2-mm-thick SiO 2 upper cladding that is deposited by plasma enhanced chemical vapor deposition at 350 6 C to protect the DPH structure and minimize light scattering. 27 …”

“…We have previously reported the fabrication of the DPH in different waveguide core (SiO 2 Ge x , HfO 2 and Si 3 N 4 ) in order to demultiplex the light in the visible wavelength range. [26][27][28][29][30] Over the years, we have demonstrated that one single planar hologram can reach a high resolution (down to 0.015 nm) in a very narrow spectral range 28 (1 nm) or be designed to work over multiple narrow bands 26 (up to 4). Here, we extend these results and demonstrate for the first time that DPHs can be used to build up a high-resolution, broadband spectrometer-on-chip with performance that are similar to conventional spectrometers.…”

Printable planar lightwave circuits with a high refractive index

“…These values of shrinkage need to be taken into consideration when designing the photonic components and can be used advantageously to minimize the residual layer thickness (RLT) underneath the imprinted components to create smaller feature sizes. We have designed a PLC integrating several components: multimode RWGs, Y-splitters [33], and digital planar holograms (DPH) [34,35]. RWGs and their bending are simulated with the beam propagation method (BPM) [36], and show that 95% of the fundamental mode can be transmitted through 90°t urn for radiuses larger than 900 μm.…”

High-Resolution, Low-Cost Spectrometer-on-Chip

“…3) Ensure the LED status in the camera is green and is blinking slowly. 4) In Matlab, Open and Run the script provided by aBeam Technologies Inc. by clicking on the RUN button in the upper bar. 5) If an error appears in the command window, refer to paragraph 5 to troubleshoot the issue.…”