Characterization of a graded index of refraction separate confinement heterostructure (GRINSCH) laser structure using contactless electroreflectance

1998 ◽  
Vol 84 (4) ◽  
pp. 2229-2235 ◽  
Author(s):  
Wojciech Krystek ◽  
M. Leibovitch ◽  
W. D. Sun ◽  
Fred H. Pollak ◽  
Godfrey Gumbs ◽  
...  
Keyword(s):  
Laser Structure ◽  
Index Of Refraction ◽  
Graded Index

Room Temperature Contactless Electromodulation Characterization of a Wafer-Sized InGaAs/GaAs/GaAlAs Grinsch Laser Structure

1995 ◽  
Vol 406 ◽  
Author(s):  
Wojciech Krystek ◽  
M. Leibovitch ◽  
Fred H. Pollak ◽  
Godfrey Gumbs ◽  
T. Konopelski
Keyword(s):  
Room Temperature ◽  
Heavy Hole ◽  
Index Of Refraction ◽  
Single Quantum Well ◽  
Graded Index ◽  
Hole Level ◽  
Function Calculation ◽  
Lasing Frequency ◽  
Good Agreement

AbstractUsing contactless electroreflectance at 300K we have characterized the complete potential profile of a pseudomorphic 0.98 μm InGaAs/GaAs/GaAlAs graded index of refraction separate confinement heterostructure laser fabricated by molecular beam epitaxy. Signals were detected from all three relevant portions of the sample. Comparison of the observed transitions from the InGaAs single quantum well (SQW) section with an envelope function calculation (including the effects of strain) made it possible to evaluate the In composition and width of SQW. These values were in good agreement with the intended parameters. The energy of 11H, the fundamental conduction to heavy-hole level (which is closely related to the lasing frequency) can easily be determined to less than ± 1 nm at 300K. From the period of the observed Franz-Keldysh oscillations from the graded GaAlAs region it was possible to directly evaluate the built-in electric field in the structure.

TEM characterization of proton-exchanged LiNbO3 optical waveguides

1986 ◽  
Vol 44 ◽  
pp. 480-481
Author(s):  
W. E. Lee
Keyword(s):  
Refractive Index ◽  
Benzoic Acid ◽  
Optical Waveguides ◽  
Total Internal Reflection ◽  
Index Of Refraction ◽  
Optical Measurements ◽  
Lithium Ions ◽  
Wide Channel ◽  
Tem Characterization

An optical waveguide consists of a several-micron wide channel with a slightly different index of refraction than the host substrate; light can be trapped in the channel by total internal reflection.Optical waveguides can be formed from single-crystal LiNbO3 using the proton exhange technique. In this technique, polished specimens are masked with polycrystal1ine chromium in such a way as to leave 3-13 μm wide channels. These are held in benzoic acid at 249°C for 5 minutes allowing protons to exchange for lithium ions within the channels causing an increase in the refractive index of the channel and creating the waveguide. Unfortunately, optical measurements often reveal a loss in waveguiding ability up to several weeks after exchange.

A Simple Method for Prediction of Effective Core Area and Index of Refraction of Single-mode Graded Index Fiber in the Low V Region

2014 ◽  
Vol 35 (4) ◽  
Author(s):  
Angshuman Majumdar ◽  
Satabdi Das ◽  
Sankar Gangopadhyay
Keyword(s):  
Refractive Index ◽  
Single Mode ◽  
Index Of Refraction ◽  
Core Area ◽  
Exact Results ◽  
Simple Method ◽  
Graded Index ◽  
Core Areas ◽  
V Region ◽  
User Friendly

AbstractBased on the simple power series formulation of fundamental mode developed by Chebyshev formalism in the low V region, we prescribe analytical expression for effective core area of graded index fiber. Taking step and parabolic index fibers as examples, we estimate the effective core areas as well as effective refractive index for different normalized frequencies (V number) having low values. We also show that our estimations match excellently with the available exact results. The concerned predictions by our method require little computation. Thus, this simple but accurate formalism will be user friendly for the system engineers.

Spectroscopic Ellipsometry Characterization of La2Ti2O7 Thin Films

1994 ◽  
Vol 361 ◽  
Author(s):  
Bryan D. Dickerson ◽  
Masaya Nagata ◽  
Y.J. Song ◽  
H.D. Nam ◽  
Seshu B. Desu
Keyword(s):  
Thin Films ◽  
Laser Energy ◽  
Pulsed Laser ◽  
Substrate Material ◽  
Index Of Refraction ◽  
Laser Deposition ◽  
Energy Substrate ◽  
Fabrication Parameters ◽  
Cauchy Model

ABSTRACTOptical properties of La2Ti2O7 thin films were investigated by spectroscopie ellipsometry and compared to those of bulk sintered ceramics. Thin films were prepared by pulsed laser deposition (PLD) from bulk targets. To separate the effects of thickness, porosity, and index of refraction on observed Ψ and δspectra in thin films, a Cauchy model for n vs. λ was developed from sintered samples, with known porosity. Assuming the effective bulk index of refraction followed the rule of mixtures, corrected models for La2Ti2O7 without porosity were used to determine thickness and porosity of thin films as a function of fabrication parameters such as laser energy, substrate material and temperature. Ellipsometry models were tested and refined through XRD, EDX, ESCA, and SEM.

Characterization of Boron Carbo-Nitride Films Deposited By Low Temperature Chemical Vapor Deposition

2003 ◽  
Vol 766 ◽  
Author(s):  
E. R. Engbrecht ◽  
C. J. Cilino ◽  
K. H. Junker ◽  
Y.M Sun ◽  
J. M. White ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Low Temperature ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Index Of Refraction ◽  
Amorphous Boron ◽  
Boron Carbonitride ◽  
Nitrogen Incorporation ◽  
Dimethylamine Borane

AbstractThis study reports low temperature chemical vapor deposition of amorphous boron carbonitride films on SiO2 using a dimethylamine borane complex at temperatures ranging from 360 to 500°C and with varying NH3 flow at 360°C. The dielectric constant, k, of the films ranged from 4.11 to 4.83, and increased with temperature while the addition of nitrogen using NH3 decreased k. The index of refraction changed correspondingly with k, ranging from 1.826 to 2.226. Higher substrate temperature caused nitrogen and carbon content to increase with additional bonding to boron. The addition of ammonia increased the N:B ratio to as high as 0.64 and reduced k to 4.11. The higher nitrogen incorporation displaced both boron and carbon in the film, leaving boron bonded primarily to nitrogen and other boron atoms. These films were amorphous with smooth surfaces of RMS roughness ranging from 0.30 nm to 0.53 nm.

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