A step-and-repeat nanoimprint lithography (SR-NIL) process on a pre-spin-coated film is employed for the fabrication of an integrated optical device for on-chip spectroscopy. The complex device geometry has a footprint of about 3 cm2 and comprises several integrated optical components with different pattern size and density. Here, a new resist formulation for SR-NIL was tested for the first time and proved effective at dramatically reducing the occurrence of systematic defects due to film dewetting, trapped bubbles, and resist peel-off. A batch of 180 dies were imprinted, and statistics on the imprint success rate is discussed. Devices were optically characterized and benchmarked to an identical chip that was fabricated by electron-beam lithography. The overall performance of the imprinted nanospectrometers is well-aligned with that of the reference chip, which demonstrates the great potential of our SR-NIL for the low-cost manufacturing of integrated optical devices.
High power (HP) laser diodes with apertures around 100um pump solid state and fiber lasers, used for material
processing. The necessity for the second stage lasers originates from the well-known limitation of brightness of laser
diodes with the aperture increase due to appearance of multiple lateral modes. For the first time we report suppression of
lateral modes of 100um wide laser diodes by digital planar holograms. Digital planar hologram narrows spectrum of
laser diodes, similar to simple gratings, used in DFB and DBR lasers.
Digital Planar Holography (DPH) has arrived due to progress in microlithography, planar waveguide fabrication, and theoretical physics. A computer-generated hologram can be written by microlithography means on the surface of a planar waveguide. DPH combines flexibility of digital holograms, superposition property of volume (thick) holograms, and convenience of microlithographic mass production. DPH is a powerful passive light processor, and could be used to connect multiple optical devices in planar lightwave circuits (PLCs), and if combined with active elements on the same chip, may perform not only analog operations but also logical ones. A DPH implementation of a multiplexer/demultiplexer with discrete dispersion is proposed and demonstrated, avoiding communication signal distortion inherent in multiplexers/demultiplexers with continuous dispersion. The concept of discrete dispersion leads to a device with a flat top transfer function without a loss penalty. The dispersion is created with custom-designed bandgaps for specific directions. A DPH hologram resembles a poly-crystal with long-range correlations, and it exhibits the properties of a quasi-crystal. Unlike photonic crystals, light in quasi-crystal may propagate in almost any direction. Single mode planar waveguides are specially designed to suppress parasitic reflections that appear due to mixture of TE-modes, TM-modes, and cladding modes. Demultiplexers with 2-32 channels were demonstrated on planar waveguides with binary single-layer lithography.
A novel concept of Photonic Bandgap Quasi-Crystal (PBQC) as a platform for planar integrated WDM optical devices is proposed. The PBQC can be lithographically fabricated in a planar waveguide as a computer-generated two-dimensional hologram. In this approach the spectral selectivity of Bragg gratings, focusing properties of elliptical mirrors, superposition properties of thick holograms, photonic bandgaps of periodic structures, and flexibility of lithography on planar waveguides are combined. In distinction to conventional combination of independent planar Bragg gratings, in PBQC we create multiple bandgaps by synthesizing a synergetic super-grating of a number of individual sub-gratings. The device spectral selectivity is determined by those of the sub-gratings. The super-grating comprises million(s) of dashes etched on an interface of a planar waveguide. Each dash is a binary feature placed by a computer program to serve simultaneously many channels. For realization of PBQC devices the software for generating super-gratings (GDS-II format) and 2-D simulation of its transfer function was developed. Direct e-beam writing and photolithography were used for manufacturing PBQC structures. For verification of the ideas behind the concept a number of multichannel MUX/DEMUX devices have been manufactured and experimentally tested. The results of detailed experimental study of 4- and 16-channel devices will be presented. Channel isolation ~30 dB was achieved in the 4-channel devices. The applications of PBQC platform for integrated light wave circuits are discussed.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.