Arpit Khandelwal

Bio: Arpit Khandelwal is an academic researcher from Indian Institute of Technology, Jodhpur. The author has contributed to research in topics: Gyroscope & Semiconductor ring laser. The author has an hindex of 4, co-authored 22 publications receiving 57 citations. Previous affiliations of Arpit Khandelwal include Birla Institute of Technology and Science & International Institute of Information Technology, Hyderabad.

Mathematical model of nonlinear coupling and its effect on rotation sensitivity of semiconductor ring laser gyroscope

Abstract: The moving population inversion gratings formed due to spatial hole burning inside a semiconductor ring laser gyroscope causes nonlinear coupling of the counter-traveling modes. We mathematically demonstrate this phenomenon using Perturbation Theory and calculate the limit imposed by it on the sensitivity of inertial rotation.

Suppression of Lock-in in Integrated Semiconductor Ring Laser Gyroscope Using Conservative Coupling

Abstract: Conservative coupling of modes in an integrated external-cavity semiconductor ring laser is used to suppress lock-in in an inertial rotation sensor. Extent of suppression is dependent on refractive index difference between active and passive cavities.

Effect of Nonlinearities on Directed Optical Logic Gates Using Integrated Semiconductor Ring Lasers

Abstract: Nonlinearities in the semiconductor ring laser (SRL) are incorporated in the analysis of directed optical logic gates and their effects on the output are studied. The paper discusses the effects of gain medium linewidth, internal quantum efficiency and self and cross gain saturation on the output of directed optical NOT gate implemented using SRLs.

Lock-in elimination by orthogonal polarization in semiconductor Ring Laser Gyroscope

Abstract: We propose a novel method to eliminate the lock-in in a Semiconductor Fiber Ring Laser Gyroscope by orthogonally polarizing the counter-traveling waves in the ring cavity. Orthogonal polarization reduces the coupling between the waves which prevents them from locking.

On the Mechanistic Origins of Toughness in Bone

Abstract: One of the most intriguing protein materials found in nature is bone, a material composed of assemblies of tropocollagen molecules and tiny hydroxyapatite mineral crystals that form an extremely tough, yet lightweight, adaptive and multifunctional material. Bone has evolved to provide structural support to organisms, and therefore its mechanical properties are of great physiological relevance. In this article, we review the structure and properties of bone, focusing on mechanical deformation and fracture behavior from the perspective of the multidimensional hierarchical nature of its structure. In fact, bone derives its resistance to fracture with a multitude of deformation and toughening mechanisms at many size scales ranging from the nanoscale structure of its protein molecules to the macroscopic physiological scale.

Recent advances in miniaturized optical gyroscopes

Abstract: Low-cost chip-scale optoelectronic gyroscopes having a resolution ≤ 10 °/h and a good reliability also in harsh environments could have a strong impact on the medium/high performance gyro market, which is currently dominated by well-established bulk optical angular velocity sensors. The R&D activity aiming at the demonstration of those miniaturized sensors is crucial for aerospace/defense industry, and thus it is attracting an increasing research effort and notably funds. In this paper the recent technological advances on the compact optoelectronic gyroscopes with low weight and high energy saving are reviewed. Attention is paid to both the so-called gyroscope-on-a-chip, which is a novel sensor, at the infantile stage, whose optical components are monolithically integrated on a single indium phosphide chip, and to a new ultra-high Q ring resonator for gyro applications with a configuration including a 1D photonic crystal in the resonant path. The emerging field of the gyros based on passive ring cavities, which have already shown performance comparable with that of optical fiber gyros, is also discussed.

Laser gyro at quantum limit

Abstract: We show that a certain fundamental limit applies to the accuracy of all optical rotation sensors which use laser light as a probe. We derive this fundamental rotation-rate uncertainty from the Heisenberg uncertainty relations and Glauber's minimum uncertainty states. The same relationship is obtained from a spontaneous-emission noise formulation. We present experimental data on a (nondithered) four-frequency ring laser gyroscope for which this limit is attained.