Effects Of Out-Coupling In Fiber Lasers

An analysis of out-coupling in a laser shows an optimum way of subtracting more output power by choosing an appropriate cavity arrangement from a high-power fiber laser. This investigation consisted in resolving analytically the effect of different cavities in our laser system and one thing that outcome was to know that a fiber laser can operate with high efficiency even with high losses in one end of the cavity (e.g. at an external diffraction grating), only if the feedback in the out-coupling end is low. Moreover, it was also found that is possible to improve the output power by reducing the feedback in the out-coupling end. Parameters considered in this resolved method are 0.1 NA, 10 μm diameter core, 200 μm inner-cladding diameter and 10 dB small-signal absorption. The fiber laser was doped with ytterbium and lases at 1080 nm, when pumped at 915 nm. The maximum pump power was set to 10 W

Multimode Interference Effects In Optical Fiber For Pressure Sensing Applications

Applications of Multimode Interference (MMI) effects in optical devices have been increased today due their excellent properties and easy fabrication. Incorporation of these effects in optical fiber has been achieved through a single-mode - multimode - single-mode (SMS) fiber structure showing high sensitivity to bending-loss phenomenon. The latter has been efficiently implemented in pressure sensing application such as is presented in this work. Basically, the SMS structure is embedded in a pressure-sensitive membrane to convert pressure in a mechanical displacement resulting in an attenuation of the transmitted intensity proportionally to the applied pressure. Under this configuration, an all-fiber pressure sensor with high sensitivity and repeatability is obtained into a pressure range from -13 psi to +13 psi. The max pressure range can be varied to 140 psi with our configuration when the membrane thickness is changed. Important features of the proposed all-fiber MMI pressure sensor are its easy-fabrication and low-cost since an inexpensive instrumentation is required. © 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE)

Design Of A Pressure Sensor Of 0-7 Bar In Fiber Optic Using Mmi Methodology

This research shows the possibility of measuring pressure in the range of 0-7 bar and the comparison against 2 commercial sensors. The technique used is based on the multimodal interference in a fiber optic singlemode-multimode- singlemode (SMS) to 1550 nm. The fiber optic is mounted on a plate of stainless steel AISI 316, where the bending of the plate will generate a curvature on the part of the multimodal fiber generating a decoupling of modes and this generates a low intensity to the output of the system. © 2013 Elsevier GmbH. All rights reserved

Integrated Multimode Interference Sensor For Bio/Chemical Applications

A novel fiber based MMI optical sensor for bio/chemical applications is demonstrated. The operating mechanism is based on the self-imaging phenomena that occurs in multimode fibers (MMF). However, the MMI sensor is highly wavelength dependent since there is D2 dependence on the wavelength response of the sensor. Therefore, using a specialty fiber, when the fiber is immersed in liquids with different refractive indexes the effective diameter is increased and the MMI response is modified. We show sensitivities on the order of 10-5, which is ideal for label-free bio/chemical sensing applications. © 2009 CBMS

Fiber Optic Pressure Sensor Using Multimode Interference

Based on the theory of multimode interference (MMI) and self-image formation, we developed a novel intrinsic optical fiber pressure sensor. The sensing element consists of a section of multimode fiber (MMF) without cladding spliced between two single mode fibers (SMF). The MMI pressure sensor is based on the intensity changes that occur in the transmitted light when the effective refractive index of the MMF is changed. Basically, a thick layer of Polydimethylsiloxane (PDMS) is placed in direct contact with the MMF section, such that the contact area between the PDMS and the fiber will change proportionally with the applied pressure, which results in a variation of the transmitted light intensity. Using this configuration, a good correlation between the measured intensity variations and the applied pressure is obtained. The sensitivity of the sensor is 3 μV/psi, for a range of 0-60 psi, and the maximum resolution of our system is 0.25 psi. Good repeatability is also observed with a standard deviation of 0.0019. The key feature of the proposed pressure sensor is its low fabrication cost, since the cost of the MMF is minimal

Optical Fiber Sensor For Pressure Based On Multimode Interference As Sensitive Element

The experimental results of applications on a novel intrinsic fiber optic pressure sensor based on multimode interference are presented. The sensitive element consists in a SM-MM-SM (MMI) fiber structure embedded in a membrane. © 2010 Optical Society of America

Intrinsic Fiber Optic Pressure Sensor Based On Multimode Interference Device As Sensitive Element

Experimental results of applications on a novel intrinsic fiber optic pressure sensor based on multimode interference are presented. The sensitive element consists in a single-mode - multimode - single-mode fiber structure embedded in a membrane pressure. © 2010 OSA /FiO/LS 2010

Intrinsic Fiber Optic Pressure Sensor Based On Multimode Interference Device As Sensitive Element

Experimental results of applications on a novel intrinsic fiber optic pressure sensor based on multimode interference are presented. The sensitive element consists in a single-mode - multimode - single-mode fiber structure embedded in a membrane pressure. © 2010 OSA /FiO/LS 2010

Integrated Fiber Based Multimode Interference Bio/Chemical Sensor

Here we designed, fabricated and tested a novel optical sensor for bio/chemical applications based on multimode interference (MMI) effects in a no-core multimode fiber that is integrated with singlemode fiber sections and PDMS microfluidic channels. © 2009 Optical Society of America

Zmanjšanje mase in napetosti v gumijastem nosilcu motorja pod vplivom mehanskih vibracij

A rubber engine mount (EM) is a mechanical coupling between the engine and the chassis, and its main function is to diminish, in the chassis, the amplitude of vibrations caused for the engine operation. Such vibrations cause discomfort for vehicle passengers and reduce the EM lifetime. To increase the comfort of vehicle passengers and the lifetime of the EM, this paper presents an EM optimization by means of reducing three main criteria: the EM mass, the displacements transmitted to the chassis, and the mechanical stress in the EM rubber core. For carrying out the EM optimization, the optimum global determination by linking and interchanging kindred evaluators (GODLIKE), assisted by artificial neural networks (ANN) and finite element method (FEM), was used. Because of the optimization process, a reduction greater than 10 % was achieved in the three criteria in comparison with a baseline design. The frequency responses were compared and showed that although the optimization was carried out for the range of 5 Hz to 30 Hz the trend of reduced responses continues beyond this range. These results increased the comfort of vehicle passengers and the lifetime of the EMin addition, the reduction of mass diminishes its production costs