This article presents a programmable device for plantar pressure measurement using fiber Bragg grating (FBG) sensors, integrated with a Python-based interface for data visualization, foot classification, and report generation. The device measures pressure at five key foot locations, classifying feet into categories such as normal, flat, pronated, supinated, and abnormal. The system demonstrates high sensitivity (355.98pm/kPa for left foot, 384.60 pm/kPa for right foot) and operates efficiently with a calibration factor of 6.4474. The interface features data storage, email functionality, and pdf report generation, making it suitable for clinical and healthcare applications. The study includes calibration and experimental validation with 70 subjects, and discusses potential future integrations, such as screen mounting for enhanced usability.

We present a quarter-phase grating cavity integrated on a silicon-on-insulator (SOI) substrate, exhibiting a high-quality factor in the optical L-band. The structure comprises a submicron grating and a quarter-phase cavity. The device was theoretically analyzed and modeled using coupled mode theory, and the spectral response was validated through finite-difference time-domain (FDTD) simulations. The fabricated device exhibited a cavity resonance at 1600 nm with a bandwidth of 20 pm, corresponding to a quality factor on the order of 1.25 & times;105. The high-quality factor was achieved through optimization of the device parameters during fabrication, where the intrinsic quality factor (QI) and the loss-limited quality factor (QL) were carefully balanced and maintained approximately equal to maximize the overall quality factor. To address fabrication challenges arising from pattern dimensions varying from 50 to 610 nm, a balanced and hybrid electron-beam lithography (EBL) patterning strategy combining conventional EBL and fixed-beam moving-stage (FBMS) approaches was adopted, minimizing fabrication-related issues at the institute level. In addition, MATLAB-based curve fitting of the experimental wavelength response was employed as an alternative characterization approach to estimate the loss parameter, coupling coefficient, and quality factor of the fabricated device, providing a useful benchmark for future device design and fabrication. Furthermore, the effects of variations in grating length, cavity length, and surrounding cladding material on the transmission spectrum were systematically investigated, offering valuable insight into the precise control of fabrication parameters required for achieving very high-Q photonic devices.

A silicon-on-insulator substrate hosts a broadband wavelength filter featuring perturbed Bragg gratings. This perturbation is induced by strategically placing waveguides near the gratings. The use of smaller grating corrugation widths leads to a larger coupling coefficient, thereby significantly improving the grating reflectivity. Theoretical analysis of this compact device reveals a simplified circuit design, which is further corroborated by finite difference time domain simulation results. The achieved broadband filter boasts a bandwidth of approximately 40 nm, coupled with an impressive extinction ratio of around 39 dB, all achieved with a modest grating length of only 20 mu m. The rate of change of the Bragg wavelength concerning the width of the perturbed waveguide is approximately 0.0625. It is noteworthy that this achievement is attained by maintaining fixed waveguide and grating parameters while selectively altering the width of the perturbed waveguide.

We demonstrate quarter phase grating cavity in SOI Substrate showing High quality factor. Grating period of 290 nm repeated 862 times with a cavity in between of length 145 nm integrated in SOI waveguide was theoretically plotted in MATLAB and the spectral result was compared with Finite Differential Time Domain simulation. The wavelength characteristic of the device showed a cavity resonant wavelength at 1608 nm with 21 pm bandwidth, resulting in the quality factor in the order of 10 ^4 .

A slow-wave structure based on a pair of an interdigital capacitor and a stepped meander line is demonstrated. The proposed structure provides not only a high slow-wave factor (SWF) but also a sharp transmission zero near passband. SWF of the structure is investigated and compared with the traditional line. SWF of the proposed structure is increased by a minimum of 177

. A nested ring resonator structure has been devised on a silicon-on-insulator platform, incorporating a feedback path through the addition of a port to the device. This design selectively enhances resonant wavelengths while effectively suppressing numerous consecutive resonant wavelengths by similar to 30dB. Consequently, it significantly expands the free spectral range (FSR) by over 85 nm, exceeding 20 times the FSR achieved without the feedback path. The resonant peak wavelength can be tuned by similar to 40nm/mu m change in the feedback path, offering a broader range for refractive index sensing. The impact of the additional phase control parameter length in the feedback path was investigated. Theoretical analysis was followed by finite differential time domain simulations to validate the results. Various device parameters were systematically adjusted to observe a substantial increase in the FSR and improved controllability over peak transmission.

It has been shown that a fundamental mode adiabatically launched into a multimode SOI waveguide with submicron grating offers well-defined flat-top bandpass filter characteristics in transmission. The transmitted spectral bandwidth is controlled by adjusting both waveguide and grating design parameters. The bandwidth is further narrowed down by cascading two gratings with detuned parameters. A semi-analytical model is used to analyze the filter characteristics (1500  nm≤λ≤1650  nm) of the device operating in transverse-electric polarization. The proposed devices were fabricated with an optimized set of design parameters in a SOI substrate with a device layer thickness of 250 nm. The pass bandwidth of waveguide devices integrated with single-stage gratings are measured to be ∼24  nm, whereas the device with two cascaded gratings with slightly detuned periods (ΔΛ=2  nm) exhibits a pass bandwidth down to ∼10  nm.

A filter device with a flat-top passband of Δλ pb > 40 nm is demonstrated using multi-mode SOI waveguide with a side-wall grating. The passband is bounded by highly extinguished sidebands of Δλ sb > 10 nm.

An integrated optical design of a rectangular-edge filter device in 250-nm silicon-on-insulator platform is proposed and demonstrated experimentally. The device is designed with a multimode waveguide (supporting at least two modes) with asymmetric side-wall grating, which is adiabatically interfaced with input/output single-mode waveguides. The input/output access waveguides are terminated with grating couplers for optical characterizations. Design parameters are optimized for a sharp-edge or nearly rectangular-edge filter response in optical C-band (1530 nm $\leq \lambda _{\text{edge}} \leq $ 1565 nm). The submicron features and the entire footprint of the devices were defined with a single-step e-beam lithography process by using negative-tone resist and subsequent dry etching of $\sim$100 nm by using an inductively coupled reactive ion etching system. All the fabricated devices exhibit a rectangular-edge filter response at $\lambda _{\text{edge}} \sim $ 1560 nm with an edge-extinction of $>$ 40 dB at the rate of 118 dB/nm. The rectangular-edge is followed by a broad pass-band of $\sim $ 40 nm till the first-order Bragg reflected wavelength of $\lambda _B^{00} \sim $ 1600 nm in the transmission characteristics obtained for 1520 nm $\leq \lambda \leq$ 1620 nm. Tunability of a rectangular-edge filter is verified with cladding refractive index change and the observed refractive index sensitivity of the edge is $\sim$18 nm/RIU. The limit of detection for 1-dB transmitted power extinction at $\lambda _{\text{edge}}$ of a typical fabricated device is estimated to be 5.3 $\times\, \text{10}^{-4}$ RIU.