Opto-Acoustic Oscillator Using Silicon Mems Optical Modulator

We show operation of a silicon MEMS based narrow-band optical modulator with large modulation depth by improving the electro-mechanical transducer. We demonstrate an application of the narrowband optical modulator as both the filter and optical modulator in an opto-electronic oscillator loop to obtain a 236.22 MHz Opto-Acoustic Oscillator (OAO) with phase noise of -68 dBc/Hz at 1 kHz offset

Electrostatic actuation of silicon optomechanical resonators

Optomechanical systems offer one of the most sensitive methods for detecting mechanical motion using shifts in the optical resonance frequency of the optomechanical resonator . Presently, these systems are used for measuring mechanical thermal noise displacement or mechanical motion actuated by optical forces. Electrostatic capacitive actuation and detection have been shown previously for silicon micro electro mechanical resonators for application in filters and oscillators. Here, we demonstrate monolithic integration of electrostatic capacitive actuation with optical sensing using silicon optomechanical disk resonators and waveguides. The electrically excited mechanical motion is observed as an optical intensity modulation when the input electrical signal is at a frequency of 235MHz corresponding to the radial vibrational mode of the silicon microdisk

Resource-use Efficiency of Paddy Cultivation in Peechi Command Area of Thrissur District of Kerala: An Economic Analysis

This study undertaken in the Peechi Command Area of Thrissur district in the Kerala state, has examined the resource productivity and allocative as well as the technical efficiency of paddy production. The study has used the primary data collected from 71 rice farmers of the command area using the stratified random sampling. The cost of cultivation of paddy in the command area has been found as Rs 21603/ha, resulting in a BC ratio of 1.34. The elasticity coefficients for chemical fertilizers, farmyard manure and human labour have been observed significant and positive. The allocative efficiency has indicated that marginal return per one rupee increase under these heads would be Rs 2.83, Rs 1.57 and Rs 1.17, respectively. The average technical efficiency of the paddy farmers in the command area has been found as 66.8 per cent. Education of the farmer and supplementary irrigation provided during the water-stress days have been identified as the factors which could enhance the technical efficiency. The study has called for an equitable distribution of canal water and enhanced extension services for resource management in the area.Agricultural and Food Policy,

A Monolithic Radiation-Pressure Driven, Low Phase Noise Silicon Nitride Opto-Mechanical Oscillator

Cavity opto-mechanics enabled radiation pressure (RP) driven oscillators shown in the past offer an all optical Radio Frequency (RF) source without the need for external electrical feedback. However these oscillators require external tapered fiber or prism coupling and non-standard fabrication processes. In this work, we present a CMOS compatible fabrication process to design high optical quality factor opto-mechanical resonators in silicon nitride. The ring resonators designed in this process demonstrate low phase noise RP driven oscillations. Using integrated grating couplers and waveguide to couple light to the micro-resonator eliminates 1/f^3 and other higher order phase noise slopes at close-to-carrier frequencies present in previous demonstrations. We present an RP driven OMO operating at 41.97MHz with a signal power of -11dBm and phase noise of -85dBc/Hz at 1kHz offset with only 1/f^2 noise down to 10Hz offset from carrier

Trends, Determinants and Constraints of Temporary Sheep Migration in Rajasthan — An Economic Analysis

The study has analysed the temporary migration of sheep as a response to the demand-supply disequilibrium of fodder and water and has explored its trends, determinants and constraints by using the data collected from rural areas of semi-arid Rajasthan. About 32 per cent of the farmers in the study area undertake temporary sheep migration. The migrating farmers have higher holding size of sheep, goat and buffaloes and are better in terms of adoption of improved sheep management practices than non-migrant farmers. The flock size, potential household labour supply and credit absorption behaviour have been reported to positively affect the odds of migration. The farmers face various en-route problems during migration, the major ones being increased morbidity, non-availability of veterinary medicines, resistance from local persons, theft and missing of sheep. The net return per animal per year has been found slightly higher in case of the non-migrant sheep flocks. The study has argued that migration of livestock is to be viewed as a method of production and adaptive mechanism evolved over the years. Efforts to sendentarise migrants without providing alternate fodder sources or productive assets of gainful employment may not be fruitful. In order to sustain the livelihood of the sheep farmers, institutional intervention to enhance accessibility to fodder and feed, veterinary services and strengthening of the extension services is needed.Sheep migration, Rajasthan, Sheep farming, Agricultural and Food Policy, Q11,