Design Rule of Mach-Zehnder Interferometer Sensors for Ultra-High Sensitivity

A design rule for a Mach-Zehnder interferometer (MZI) sensor is presented, allowing tunable sensitivity by appropriately choosing the MZI arm lengths according to the formula given in this paper. The present MZI sensor designed by this method can achieve an ultra-high sensitivity, which is much higher than any other traditional MZI sensors. An example is given with silicon-on-insulator (SOI) nanowires and the device sensitivity is as high as 106 nm/refractive-index -unit (or even higher), by choosing the MZI arms appropriately. This makes it possible for one to realize a low-cost optical sensing system with a detection limit as high as 10−6 refractive-index-unit, even when a cheap optical spectrum analyzer with low-resolution (e.g., 1 nm) is used for the wavelength-shift measurement.

Perancangan dan Simulasi Microring Resonator Optik dengan Variasi Indeks Bias Cladding untuk Aplikasi Sensor Amonia pada Air Tambak

Kualitas air merupakan faktor yang sangat penting dalam budidaya perikanan. Salah satu faktor yang mempengaruhi kualitas air adalah konsentrasi amonia. Oleh karena itu dalam budi daya perikanan dibutuhkan sensor amonia untuk memantau konsentrasi amonia. Sensor berbasis optical microring resonator optik (MRRO) telah menarik banyak perhatian karena ukurannya yang sangat kecil dan sensitifitasnya yang lebih tinggi dibandingkan sensor lain. Dalam penelitian ini telah dirancang dan disimulasikan sensor amonia berbasis MRRO dengan jari-jari ring 5 μm, lebar waveguide 0,1 μm dan gap 0,1 μm. Sensor menunjukkan linearitas yang sangat baik dengan sensitifitas sensor sebesar 168,82 nm/RIU (refractive index unit) dan 0,0973 nm/% amonia dalam air, dan batas deteksi 0,1% konsentrasi amonia dalam air.Water quality is a very important factor in aquaculture. One of the factor that determines water quality is ammonia concentration. Therefore, in aquaculture ammonia sensor is needed to monitor ammonia concentration. Optical microring-resonator(OMRR)-based sensors have gained a lot of interest because of it’s small size and higher sensitivity compared to other sensors. In this research, an OMRR-based ammonia sensor with ring radius of 5 μm, waveguide width of 0,1 μm, and gap of 0,1 μm has been designed and simulated. The sensor showing a very good linearity with sensor’s sensitivity of 168,82 nm/RIU (refractive index unit) and 0,0973 nm/% ammonia in the water, and detection limit of 0,1% ammonia on the water.

A Compact Robust OWLS System for Biosensing of Multiple Samples

A compact multichannel and portable OWLS (Optical Waveguide Light Mode Spectroscopy) biosensor will be presented. With a sensitivity of 16.3°/RIU (degrees per refractive index unit) it incorporates on-line reference and high potential for further miniaturization.

Garnets from the Eilat area, southern Israel

SummaryGarnets from twenty-eight pegmatites, schists, and gneisses from the crystalline massif of Eilat have been examined. Refractive index, unit-cell edge, MnO and FeO content were determined in 19 samples. Three chemical analyses are given. The garnets fall into two distinct groups, the pegmatite garnets (spessartine-rich, almandine to spessartine) and metamorphic garnets (nearly pure almandine). Garnets occurring in pegmatite-like granitoid veins cutting through the schists are shown to belong to the second (metamorphic) group. The pegmatite garnets again fall into two groups of different spessartine content.