scholarly journals Refractive Index of Heavily Germanium-Doped Gallium Nitride Measured by Spectral Reflectometry and Ellipsometry

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7364
Author(s):  
Dario Schiavon ◽  
Robert Mroczyński ◽  
Anna Kafar ◽  
Grzegorz Kamler ◽  
Iryna Levchenko ◽  
...  
Keyword(s):  
Refractive Index ◽  
Gallium Nitride ◽  
Production Process ◽  
Laser Diodes ◽  
Index Of Refraction ◽  
Aluminium Gallium Nitride ◽  
Process Yield ◽  
Index Contrast ◽  
Cladding Layers ◽  
Lattice Matched

Gallium nitride (GaN) doped with germanium at a level of 1020 cm−3 is proposed as a viable material for cladding layers in blue- and green-emitting laser diodes. Spectral reflectometry and ellipsometry are used to provide evidence of a reduced index of refraction in such layers. The refractive-index contrast to undoped GaN is about 0.990, which is comparable to undoped aluminium gallium nitride (AlGaN) with an aluminium composition of 6%. Germanium-doped GaN layers are lattice-matched to native GaN substrates; therefore, they introduce no strain, cracks, and wafer bowing. Their use, in place of strained AlGaN layers, will enable significant improvements to the production process yield.

scholarly journals Introducing SiOC as novel dielectric platform for photonic integration

2020 ◽  
Vol 16 (1) ◽  
pp. 81-84
Author(s):  
Faisal Ahmed Memon ◽  
Imran Ali Qureshi ◽  
Abdul Latif Memon ◽  
Erum Saba
Keyword(s):  
Thin Films ◽  
Refractive Index ◽  
Large Scale ◽  
Rf Sputtering ◽  
Silicon Oxycarbide ◽  
Index Of Refraction ◽  
Photonic Integration ◽  
Index Contrast ◽  
Photonic Waveguides ◽  
First Time

In this paper, we explore the potential of silicon oxycarbide (SiOC) as a novel dielectric platform for integrated photonics and present photonic waveguides. The interesting features of SiOC are its wide tunable window of refractive index and low absorption, that are considered key for large scale photonic integration. It is possible to tune SiOC refractive index from silica glass (1.45) to silicon carbide (3.2) that allows to realize a myriad of photonic passive devices. We have prepared SiOC thin films by employing reactive RF sputtering technique and examined their structural and optical properties using several techniques such as SEM, AFM, ellipsometry, profilometry, and prism coupling. For the first time, SiOC thin films with index of refraction of 1.554 at the standard telecom wavelength 1.55 μm are exploited for the fabrication of photonic waveguides and the propagation losses around 0.37 dB/mm are measured. SiOC photonic waveguides exhibit relatively higher index contrast with silica cladding when compared to traditional Ge-doped silica platform.

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.

scholarly journals Optical Sensitivity of Waveguides Inscribed in Nanoporous Silicate Framework

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 123
Author(s):  
Zhong Lijing ◽  
Roman A. Zakoldaev ◽  
Maksim M. Sergeev ◽  
Andrey B. Petrov ◽  
Vadim P. Veiko ◽  
...  
Keyword(s):  
Refractive Index ◽  
Near Field ◽  
Experimental Studies ◽  
Laser Pulses ◽  
Femtosecond Laser Pulses ◽  
Direct Writing ◽  
Sensor Applications ◽  
Refractive Index Contrast ◽  
Optical Sensitivity ◽  
Index Contrast

Laser direct writing technique in glass is a powerful tool for various waveguides’ fabrication that highly develop the element base for designing photonic devices. We apply this technique to fabricate waveguides in porous glass (PG). Nanoporous optical materials for the inscription can elevate the sensing ability of such waveguides to higher standards. The waveguides were fabricated by a single-scan approach with femtosecond laser pulses in the densification mode, which resulted in the formation of a core and cladding. Experimental studies revealed three types of waveguides and quantified the refractive index contrast (up to Δn = 1.2·10−2) accompanied with ~1.2 dB/cm insertion losses. The waveguides demonstrated the sensitivity to small objects captured by the nanoporous framework. We noticed that the deposited ethanol molecules (3 µL) on the PG surface influence the waveguide optical properties indicating the penetration of the molecule to its cladding. Continuous monitoring of the output near field intensity distribution allowed us to determine the response time (6 s) of the waveguide buried at 400 µm below the glass surface. We found that the minimum distinguishable change of the refractive index contrast is 2 × 10−4. The results obtained pave the way to consider the waveguides inscribed into PG as primary transducers for sensor applications.

Integrated platform based on high refractive index contrast waveguide for optical guiding and sorting

2010 ◽  
Author(s):  
Balpreet Singh Ahluwalia ◽  
Olav Gaute Hellesø ◽  
Ananth Z. Subramanian ◽  
James S. Wilkinson ◽  
Jie Chen ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Refractive Index ◽  
Refractive Index Contrast ◽  
Integrated Platform ◽  
Index Contrast

scholarly journals Air-trench splitters for ultra-compact ring resonators in low refractive index contrast waveguides

2008 ◽  
Vol 16 (1) ◽  
pp. 456 ◽  
Author(s):  
Nazli Rahmanian ◽  
Seunghyun Kim ◽  
Yongbin Lin ◽  
Gregory P. Nordin
Keyword(s):  
Refractive Index ◽  
Ring Resonators ◽  
Compact Ring ◽  
Refractive Index Contrast ◽  
Index Contrast ◽  
Low Refractive Index

Direct laser writing and applications of dielectric microstructures with low refractive index contrast

2011 ◽  
Author(s):  
Vygantas Mizeikis ◽  
Vytautas Purlys ◽  
Lina Maigyte ◽  
Kestutis Staliunas ◽  
Saulius Juodkazis
Keyword(s):  
Refractive Index ◽  
Direct Laser Writing ◽  
Laser Writing ◽  
Refractive Index Contrast ◽  
Direct Laser ◽  
Index Contrast ◽  
Low Refractive Index

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.

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