Influence of depth of intermediate layer on optical power distribution in W-type optical fibers

2012 ◽  
Vol 51 (20) ◽  
pp. 4896 ◽  
Author(s):  
Ana Simović ◽  
Alexandar Djordjevich ◽  
Svetislav Savović
Keyword(s):  
Optical Fibers ◽  
Power Distribution ◽  
Intermediate Layer ◽  
Optical Power

Use of various keratometry data (ring and zone) in trifocal IOL calculation

2021 ◽  
pp. 53-56
Author(s):  
A.D. Loginova ◽  
◽  
S.V. Shukhaev ◽  
S.S. Kudlakhmedov ◽  
E.V. Boiko ◽  
...  
Keyword(s):  
Power Distribution ◽  
Optical Power ◽  
Iol Implantation ◽  
Universal Formula ◽  
Significant Difference ◽  
Trifocal Iol ◽  
Iol Calculation ◽  
Km Value ◽  
Tomographic Data ◽  
Corneal Refractive Power

Purpose. To compare the results of trifocal IOL calculation using various corneal tomographic data (ring and zone). Methods. This retrospective study involved 46 patients (46 eyes), underwent cataract surgery with trifocal IOL implantation (AcrySof IQ PanOptix). The calculation was performed using Tomey OA-2000 according to 2 formulas (Barrett II Universal, Olsen). Keratometry values included Km (the average of two main meridians of a cornea) provided by Pentacam HR Power Distribution Apex map, which describes total corneal refractive power (TCRP) with diameter of 3.0, 4.0 and 5.0 mm on a ring and zone. Mean (MAE) and median (MedAE) predicted postoperative refraction errors were assessed after surgery. Results. Mean Km value on 3 mm zone and ring was: 42.75±1,46 D and 42,91±1,43 D, respectively (p<0,0001). Mean Km on 4 mm zone and ring was: 42.6±1.5 D and 43.3 ± 1.5 D, respectively (p <0.005). Mean Km value on 5 mm zone and ring was: 43,09±1,5 D and 43,55±1,48 D, respectively (p<0,0001). Calculations using the Barrett II Universal formula revealed significant difference between MAE and MedAE of the predicted postoperative refraction on 5mm zone and ring (p=0.045). When using the Olsen formula in the calculations, significant difference was revealed using the Km data with a diameter of 3 mm and 5 mm (p=0.001 и p=0.009, respectively). The calculation on 3 mm ring was more accurate than for 3 mm zone. With a 5 mm diameter, the calculation is more accurate according to the zone data. Conclusion. Mean Km value on Power Distribution Apex map according to ring is significantly greater then according to zone. 1) The calculation of the trifocal IOL based on the TCRP zone data is reliably more accurate than the ring data according to both formulas (Barrett II Universal and Olsen) with a diameter of 5 mm. 2) According to the Olsen formula with a diameter of 3 mm, the calculation of the optical power of trifocal IOL based on TCRP ring data is more accurate. Key words: IOL calculation, Trifocal IOL, corneal topography

scholarly journals EQUILIBRIUM MODE DISTRIBUTION IN W-TYPE GLASS OPTICAL FIBERS

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Svetislav Savović ◽  
Ana Simović ◽  
Aleksandar Djordjevich ◽  
Aco Janićijević
Keyword(s):  
Optical Fibers ◽  
Coupling Strength ◽  
Intermediate Layer ◽  
Power Flow ◽  
Flow Equation ◽  
Coupling Length ◽  
Modal Dispersion ◽  
Equilibrium Mode ◽  
Bending Loss

Power flow equation is used to calculate equilibrium mode distribution in W-type glass optical fibers. It has been shown how the coupling length for achieving the equilibrium mode distribution in W-type glass optical fibers varies with the depth and width of the intermediate layer and coupling strength for different widths of launch beam distribution. W-type optical fibers have shown effectiveness in reducing modal dispersion and bending loss.

scholarly journals Macrobending Loss Analysis on Singlemode-Multimode-Singlemode Fiber Optic Core

2019 ◽  
Vol 9 (2) ◽  
pp. 11-15
Author(s):  
Sisca Arisya Harry Andhina
Keyword(s):  
Light Source ◽  
Optical Fibers ◽  
Fiber Optic ◽  
Optical Power ◽  
Single Mode ◽  
Fiber Optic Cable ◽  
Power Meter ◽  
Loss Analysis ◽  
Measurement Results ◽  
Source Test

Macrobending often occurs in optical fibers that embedded in the ground due to shifting of soil or rocks in the ground causing interference in transmission. In this study used single-mode-multimode-singlemode fiber optic cable connected manually and axially measured using a light source test equipment and optical power meter and the results will be compared. The measurement results obtained the greater  value of macrobending losses with the smaller the diameter of the winding, and the greater the number of turns. The highest value of macrobending losses in multimode cables is -1.48dB at 0.5cm diameter with 5 turns, highest value of macrobending losses on single mode cables is -12.73dB at 0.5cm diameter with 5 turns,  lowest value of macrobending losses for multimode cables is -0.44dB at 5cm diameter with 1 twist, lowest macrobending losses in singlemode cables is -1.69dB at 5cm diameter with 1 twist. While the value of macrobending losses on axially connected SMS cables shows the highest value of macrobending losses on multimode cables is -1.12dB in diameter of 0.5cm with 5 turns,  highest value of macrobending losses on singlemode cables is -1.18dB at diameter of 0.5cm with 5 turns,  lowest value for macrobending losses on multimode cables is -0.66dB at 5cm in diameter with 1 twist, the smallest value for macrobending losses on singlemode cables is -0.27dB at 5cm diameter with 1 twist . The measurement results also showed that the macrobending losses of manually connected SMS cables were greater than the macrobending losses of axially connected SMS cables.

scholarly journals Global characterization of optical power propagation in step-index plastic optical fibers

2006 ◽  
Vol 14 (20) ◽  
pp. 9028 ◽  
Author(s):  
Javier Mateo ◽  
M. Angeles Losada ◽  
Ignacio Garcés ◽  
Joseba Zubia
Keyword(s):  
Optical Fibers ◽  
Optical Power ◽  
Step Index ◽  
Plastic Optical Fibers

scholarly journals Characterization of a Y-Coupler and Its Impact on the Performance of Plastic Optical Fiber Links

Fibers ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 96 ◽  
Author(s):  
Alicia López ◽  
M. Losada ◽  
Javier Mateo ◽  
N. Antoniades ◽  
Xin Jiang ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Power Distribution ◽  
Glass Fibers ◽  
Single Mode ◽  
Transmission Properties ◽  
Modal Power ◽  
Custom Made ◽  
Plastic Optical Fibers ◽  
The Impact

Couplers and splitters are common devices in single-mode and multi-mode glass fibers applications, where they perform a variety of functions. However, when switching to plastic optical fibers (POFs), there is a shortage of commercial devices, which are usually custom-made. The problem with these devices is that modal power distribution in POFs is easily modified by spatial disturbances that produce a localized strong power transfer between modes, thus changing their transmission properties. In this work, a commercial Y-coupler designed for POFs is experimentally characterized. Measurements of its spectral, spatial and temporal characteristics have been performed, including insertion loss as a function of wavelength, angular power distribution, and frequency response. The obtained results show that this device has an equalizing effect over the power spatial distribution that reduces the fiber bandwidth, demonstrating the importance of considering the impact of this type of devices on the transmission properties of any POF system.

Coupling. Non-Symmetric Behaviour of a Joint Between Multimode Fibers

1984 ◽  
Vol 5 (3) ◽  
Author(s):  
G. Cancellieri ◽  
U. Ravaioli
Keyword(s):  
Power Distribution ◽  
Dispersion Compensation ◽  
Coupling Efficiency ◽  
Optical Power ◽  
Optical Source ◽  
Multimode Fibers ◽  
Intermodal Dispersion ◽  
Intentional Mode ◽  
Different Characteristics ◽  
Mode Mixing

SummaryWhen two different multimode fibers are jointed together, mode mixing and mode filtering take place, with different characteristics in the two directions, leading to a non-symmetric behaviour. A detailed analysis of the power transitions among the guided modes at the joint is presented here. Explicit formulas for coupling efficiency and intermodal dispersion compensation are derived. The intentional mode mixing which is produced by suitable beam-launchers, in order to reach an optical power distribution independent of that of the optical source, is also investigated.

A rigorous analysis of the power distribution in plastic clad annular core optical fibers

Optik ◽  
2002 ◽  
Vol 113 (11) ◽  
pp. 481-488 ◽  
Author(s):  
P.K. Choudhury ◽  
Toshihiko Yoshino
Keyword(s):  
Optical Fibers ◽  
Power Distribution ◽  
Rigorous Analysis

scholarly journals Design of a Four-Branch Optical Power Splitter Based on Gallium-Nitride Using Rectangular Waveguide Coupling for Telecommunication Links

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Retno W. Purnamaningsih ◽  
Nji R. Poespawati ◽  
Elhadj Dogheche
Keyword(s):  
Gallium Nitride ◽  
Power Distribution ◽  
Optical Power ◽  
Power Input ◽  
Input Power ◽  
Propagation Length ◽  
Power Splitter ◽  
Excess Loss ◽  
Total Input ◽  
Rectangular Waveguides

This paper reports design of a simple four-branch optical power splitter using five parallel rectangular waveguides coupling in a gallium-nitride (GaN) semiconductor/sapphire for telecommunication links. The optimisation was conducted using the 3D FD-BPM method for long wavelength optical communication. The result shows that, at propagation length of 925 μm, the optical power input was successfully split into four uniform output beams, each with 24% of total input power. It is also shown that the relative output power distribution is almost stable through the C-band range. At the operating wavelength of 1.55 μm, the proposed power splitter has an excess loss lower than 0.2 dB. This study demonstrates the opportunity to develop optical interconnections from UV-Visible to near IR wavelengths.

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