Interferometric sensing platform with dielectric nanostructured thin films

A new interferometer-based optical sensing platform with nanostructured thin films of ZrO2 or TiO2 as sensing environment has been developed. With the application of an IC compatible Si3N4 waveguide technology, Mach-Zehnder interferometer devices have been fabricated. The application of the glancing angle deposition technique allowed fabrication of nanostructured thin films as the optical sensing environment. Sensing ability of fabricated devices has been demonstrated through the refractive index measurement of a known gas. The transmission spectra and time response measurements have demonstrated a maximum phase shift of ΔΦ=Π/10 and a |ΔPout|=0.65 dBm. Devices with TiO2 film on the sensing region performed much better than devices with ZrO2, with sensitivity twice as high

Optimization of Magnetotransistor Structure in CMOS Texhnology

Experimental results are presented for the comparison of a novel CMOS based magnetic sensor and a lateral magnetotransistor. Results indicating a dramatic increase in sensitivity are given and a linear response is obtained. An improvement in the device sensitivity of four times was measured and a ma

Modeling of photonic crystals using a real-valued transmission line matrix method

A stable real-valued transmission line matrix (TLM) method for simulating periodic photonic structures was presented. The method was the circuit-type implementation of the periodicity (Bloch) condition at the sidewalls of the unit cell under simulation. It was observed that the enforcement of Bloch boundary conditions at the sidewalls while preserving energy, results in a stable TLM scheme free of high-frequency noise

A meshless based solution to vectorial mode fields in optical microstructured waveguides

A meshless solution to vectorial mode fields has been applied to various micro-structured optical waveguides. The Finite Cloud Method (FCM), has been used to solve coupled field equations for both transverse components of the magnetic field as well as the effective index of refraction for the waveguides. Two methods using either a step-index or a graded-index have been implemented and compared. An approximation to the solution is found using a distribution of points and a cloud about each point, with no mesh and minimal geometric linking knowledge between the points. This gives the ability to use a highly irregular point distribution which can be easily modified or tailored to micro-structured fibers in order to accurately represent the vectorial modal solution. In addition, the use of Bayliss-Gunzburger-Turkel-like transparent boundary conditions (TBC) and an iterative process is compared with a perfectly matched layer (PML), both of which allow for the solution of leaky modes for the structures. Results for ridge waveguides and solid core fibers having low index contrast are in high agreement with the solutions from commercial solvers. Further results with high contrast air hole structures are compared with other solution methods giving promising results and highlight this methods versatility, accuracy and efficiency for a wide range of problems

A meshless based solution to vectorial mode fields in optical micro-structured waveguides using leaky boundary conditions

Leaky boundary conditions are implemented in a meshless numerical method to solve vectorial mode fields in optical waveguides which allow for the solution of both guided and leaky modes. The modes are found using an approximating solution, the Finite Cloud Method (FCM), to the coupled field equations of the transverse components of the magnetic field. In this paper we extend the method by implementing two absorbing boundary conditions, Transparent Boundary Conditions (TBC) and Perfectly Matched Layers (PML), to solve the leaky modes for several microstructured air hole waveguides. Presented are methods to further refine the boundary conditions and to stabilize the solutions. A comparison between these methods and previously published results show close agreement. Finally, we conclude that the TBC boundary condition is the superior method due to its robustness and lack of fitting parameters

Floquet analysis of parametric Huygens' metasurfaces

An exact Floquet analysis is proposed to determine the steady-state response a uniform parametric Huygens' metasurface. Under periodic modulation of the resonant frequencies of the Lorentzian surface susceptibilities of the metasurface, the unknown scattered fields are expressed as Floquet series. Using the Floquet form of the fields in conjunction with the Generalized Sheet Transition Conditions (GSTCs), the amplitudes of the new harmonic components are then conveniently determined by solving the resulting set a linear fields equations

Robust simulation of opto-electronic systems by alternating complex envelope representations

The increased use of optics in information processing and transmission systems motivates the development of self-consistent opto-electronic transient simulators. This letter presents a technique to significantly improve the DC and transient convergence behavior of a modified nodal analysis based optoelectronic simulation framework by allowing optical device models to be switched between a linear formulation using real and imaginary fields to a non-linear magnitude and phase representation. Configurable multilayer filters and optical ring modulators are used as examples to demonstrate the effectiveness of this approach in obtaining robust simulation convergence

Finite-difference modeling of broadband Huygens' metasurfaces based on generalized sheet transition conditions

An explicit time-domain finite-difference technique for modeling zero-thickness Huygens' metasurfaces based on generalized sheet transition conditions (GSTCs) is proposed and demonstrated using full-wave simulations. The Huygens' metasurface is modeled using electric and magnetic surface susceptibilities, which are found to follow a double-Lorentz dispersion profile. To solve zero-thickness Huygens' metasurface problems for general broadband excitations, the double-Lorentz dispersion profile is combined with GSTCs, leading to a set of first-order differential fields equations in time domain. Identifying the exact equivalence between Huygens' metasurfaces and coupled RLC oscillator circuits, the field equations are then subsequently solved using standard circuit modeling techniques based on a finite-difference formulation. Several examples, including generalized refraction, are shown to illustrate the temporal evolution of scattered fields from the Huygens' metasurface under plane-wave normal incidence, in both harmonic steady-state and broadband regimes. In particular, due to its inherent time-domain formulation, a significant strength of the methodology is its ability to model time-varying metasurfaces, which is demonstrated with a simple example of a pumped metasurface leading to new frequency generation and wave amplification

Thermal models for optical circuit simulation using a finite cloud method and model reduction techniques

This paper presents a procedure for the creation of versatile and powerful thermal compact models of integrated optical devices and demonstrates their use in an optical circuit level simulator. A detailed 3-D model of the device is first built using a meshless finite cloud method, producing a large linear sparse set of equations. This model is then reduced to a compact representation using a Krylov subspace model reduction (MR) technique. Such a reduced model is described by small dense matrices, but can reproduce the original temperature distribution within acceptable error. Three devices are used as demonstration models for the technique: a microdisc laser and two microring-based devices, a modulator, and an optical switch. All three devices are built in a silicon on oxide platform. Using MR the linear systems describing these models are reduced from thousands of unknowns to systems with less than 100 reduced variables. It is then demonstrated how the reduced compact models can be linked together to describe a complete optical system with solution errors of lower than 1%. Finally, it is shown how this reduced thermal model can be utilized in a circuit level opto-electronic circuit simulator and simulations are presented, demonstrating the effectiveness of the reduced models in speeding up simulation times or enabling otherwise intractable problems