In this paper a subwavelength ring resonator based on array of silicon nanowire is proposed. Silicon-on-Insulator (SOI) based structure is employed to couple resonance wavelength from one waveguide to another waveguide in opposite direction via ring waveguide structure. Silicon nanowire waveguide having standard SOI height technology of 220nm is considered for designing of proposed ring resonator structure. Replacing silicon nanowire technology with conventional integrated optics takes the photonics to a new level, where the cavity between nanowires serves as a nice optical confinement region. The advantage of using silicon nanowire over ring resonator can be seen in the narrowness of the filtered wavelength ranges and hence the sharpness of the filtering process. This structure finds its application as a notch filter to filter out the C-band wavelengths by adjusting waveguide geometrical parameters.
Structure of a curve slot waveguide based on the Si3N4- SiO2 index contrast is demonstrated by using full vectorial Finite Element Method (FEM). Modal analysis of the device has been performed in quasi TM mode at 1550nm wavelength. Confinement factor and birefringence property of curve slot waveguide has been discussed for variations in slot width. Effective refractive index of the device has also been calculated for the large wavelength range. The waveguide is designed with silicon nitride in complementary to silicon, so it provides low loss due to roughness of wall in large bandwidth range. Photonic Integrated Circuit (PIC) based curve slot waveguide is found a good configuration of waveguide to confine the light in slot region and in terms of material integration and fabrication.
In this paper a subwavelength waveguide-to-fiber coupler based on two dimensional periodic grating is proposed. In this approach Silicon-On-Insulator (SOI) based structure is employed to couple the radiated mode field inside the core of optical fiber. Rectangular photonic integrated circuit (PIC) waveguide having standard SOI height technology of 220 nm is considered for guiding optical field inside on chip waveguide.
A highly sensitive and high resolution Interrogation setup for Fiber Bragg Grating (FBG) based sensing to measure low strain variation (i.e ~100με) effectively is being proposed in this manuscript. This system uses edge detection interrogation scheme using two optical signals generated through carrier compressed modulation scheme. Here, Dual Drive Mach-Zehnder Modulator (DD-MZM) is employed to generate carrier suppressed first order sidebands, which are then used as two optical signals and detected on two different power meters. Differential power measurement technique is used to calculate change in wavelength or applied strain at detector end. This system can provide system sensitivity as high as 0.3193 dBm.με-1 and resolution upto 31.31nε in term of strain or 37.2fm in terms of wavelength. Which is much higher than present commercially available interrogation system (~0.8με). The proposed interrogation system can be employed in biomedical sensing to monitor cardiac and respiratory activity even during Magnetic Resonance Imaging (MRI) scanning condition as they are not prone to any electromagnetic interference.
Detection of DNA hybridization by Silicon Nanowire Optical Rectangular Waveguide (SNORW) using full vectorial finite element method is presented. Waveguide is designed to detect DNA hybridization through change in refractive index of single strand and double strand DNA. SNORW having high surface to volume ratio with optical confinement inside low index region permits a compact sensor. Waveguide sensing characteristics such as change in effective refractive index, waveguide sensitivity and power confinement is evaluated for optimized silicon wired waveguide.
A silicon nanowire waveguide based glucose sensor has been proposed and analyzed. It uses minimal invasive approach to measure the glucose level in a very small blood sample, where, Ethylene-diamine-tetraacetic acid (EDTA) as an anticoagulant, sodium fluoride as preservative and blood sample measurand are added in the ratio of 8:1:1. As the glucose concentration in the blood sample varies, the refractive index (RI) of blood changes, accordingly the refractive index of the solution with 10% blood also gets altered, which in turn to deviated response of the biosensor. The prediction of glucose level is affirmed by taking this solution as a cladding measurand of waveguide. Silicon Nanowire Optical Rectangular Waveguide (SNORW) is proposed for the first time in bio-sensing application for the detection of blood glucose. It works on the principle of detecting changes in refractive index for various concentrations of glucose level ranging from 10 mg/dl to 200 mg/dl. Additionally, SNORW sensor characteristics are compared accordingly with the slot waveguide sensors.