Jonathan S. Maikisch

Optimization of anisotropically etched silicon surface-relief gratings for substrate-mode optical interconnects.

The optimum profiles of right-angle-face anisotropically etched silicon surface-relief gratings illuminated at normal incidence for substrate-mode optical interconnects are determined for TE, TM, and random linear (RL) polarizations. A simulated annealing algorithm in conjunction with the rigorous coupled-wave analysis is used. The optimum diffraction efficiencies of the -1 forward-diffracted order are 37.3%, 67.1%, and 51.2% for TE-, TM-, and RL-polarization-optimized profiles, respectively. Also, the sensitivities to grating thickness, slant angle, and incident angle of the optimized profiles are presented.

Optimum parallel-face slanted surface-relief gratings

Using a combination of rigorous coupled-wave analysis and simulated annealing, parallel-face slanted surface-relief gratings (PFSSRGs) are optimized. For substrate-mode optical interconnects, profiles are presented for both polymer and silicon PFSSRGs for both TE and TM polarizations at normal incidence with grating periods designed to give a 45 degrees output angle in the negative-first forward-diffracted order. The resulting diffraction efficiencies range from 70% to 99%, with a majority of the optimized profiles yielding over 90%. Optimized polymer profiles for TE and TM polarizations exhibit similar high diffraction efficiencies, but the TM profiles generally require greater groove depths. Silicon profiles optimized for TM polarization have greater diffraction efficiencies than those for TE polarization. Profiles that can feasibly be fabricated are identified, and sensitivities to groove depth, filling factor, slant angle, and incident angle are shown to be modest.

Compact silicon diffractive sensor: design, fabrication, and prototype.

An in-plane constant-efficiency variable-diffraction-angle grating and an in-plane high-angular-selectivity grating are combined to enable a new compact silicon diffractive sensor. This sensor is fabricated in silicon-on-insulator and uses telecommunications wavelengths. A single sensor element has a micron-scale device size and uses intensity-based (as opposed to spectral-based) detection for increased integrability. In-plane diffraction gratings provide an intrinsic splitting mechanism to enable a two-dimensional sensor array. Detection of the relative values of diffracted and transmitted intensities is independent of attenuation and is thus robust. The sensor prototype measures refractive index changes of 10(-4). Simulations indicate that this sensor configuration may be capable of measuring refractive index changes three or four orders of magnitude smaller. The characteristics of this sensor type make it promising for lab-on-a-chip applications.

Functional demonstration of a compact silicon diffractive sensor for toluene.

A compact silicon diffractive sensor detecting toluene in solution is demonstrated. This sensor is fabricated in silicon-on-insulator and utilizes a standard telecommunications wavelength. In-plane diffraction gratings enable micrometer-scale device sizes and intensity-based (as opposed to spectral-based) detection for increased integrability. Precise grating design enables 2-D sensor arrays without the addition of separate optical splitters. Detection of the relative diffracted and transmitted intensities is independent of attenuation and is thus robust. This proof-of-concept sensor is shown to measure toluene concentrations as low as 100 parts per million, corresponding to a refractive index change of 3×10(-4). In addition, a linear sensor array with individual sensor addressability and 2-D array capability is demonstrated. The characteristics of this sensor type make it promising for field-deployable lab-on-a-chip applications.

Compact Silicon Diffractive Sensor for Toluene

A compact silicon diffractive sensor for toluene is experimentally demonstrated. A linear portion of a two-dimensional sensor array is prototyped. The configuration features micron-scale device sizes and attenuation-independent intensity-based measurement (as opposed to spectral-based).

Compact Silicon Diffractive Sensor Performance

Simulation, fabrication, and experimental results for the compact silicon diffractive sensor platform are presented. This configuration is independent of interaction length and attenuation and capable of measuring refractive index changes of 10-8without spectral measurement.

Compact Silicon-on-Insulator Diffractive Sensor Design

A compact, integrated silicon-on-insulator optical sensor design based on in-plane diffraction gratings for microfluidic detection of analytes is presented and analyzed. Optimization, characterization, and sensitivity analysis are performed. Preliminary experimental and fabrication results are presented.

A Compact Integrated Chemical/Biological Sensor

A compact, integrated silicon-on-insulator optical sensor design based on in-plane diffraction gratings for microfluidic detection of gaseous and liquid analytes is presented and analyzed. Optimization, characterization, and sensitivity analysis are performed with rigorous coupled-wave analysis.

Optimization of Anisotropically Etched Silicon Surface-Relief Gratings for Substrate-Mode Optical Interconnects

A simulated annealing algorithm in conjunction with the rigorous coupled-wave analysis (RCWA) is applied to determine the optimum profiles of right-angle-face anisotropically etched silicon (Si) gratings. The sensitivities of the optimized profiles are presented.