bluuebunny/crossref_metadata_2025 huggingface dataset:
Wide Range and Linearity of Near-UV Induced Index Change in Hydrogen-Loaded Fibers: Applications for Bragg Grating Fabrication
Authors: Grubsky V. , Starodubov D. S. , Feinberg J.
Published: December 2022

Because of their potential applications in fiber communication systems, there is a considerable interest and possible profit in exploring new techniques for fabricating fiber Bragg gratings. For example, the photosensitivity of Ge-doped fiber to mid-UV (240 nm) light can be substantially improved by loading the fiber with molecular hydrogen before writing [1-3]. However, the strong absorption of 240 nm light in the fiber’s core causes the induced index change across the core to be non-uniform [4]. Also, strong absorption of 240 nm light can heat the core and cause a thermal reaction with molecular hydrogen [3] that saturates the index change and substantially reduces the contrast of the final grating.
Strong Higher-Order Fiber Bragg Gratings Written with an Amplitude Mask
Authors: Wagener J. L. , Espindola R. P. , Vengsarkar A. M.
Published: December 2022

Reflective Bragg gratings have been written in optical fibers using UV induced index changes. Initial work used a standing wave interference pattern set up by light launched down the fiber core.1 The more versatile techniques of side-writing using bulk interferometric fringes2 and phase-masks3 followed. The field of phase-mask-written Bragg gratings in germano-silicate fibers has matured with the use of specially designed high-photosensitivity fiber and hydrogen loading.4 While gratings written with these methods can be precisely tailored in spectral shape, bandwidth and strength, a precise mask, a coherent laser, and very stable alignment during the exposure are needed. Multiple grating applications, including weak pump-diode stabilizers, fiber laser mirrors, and grating sensors may not require the high precision gratings produced with the phase mask method, but would benefit from an inexpensive mass production technique. In this paper we demonstrate an amplitude mask exposure technique to create strong higher order Bragg reflectors with minimal optics.
Rapid Thermal Annealing of Chalcogenide glasses for Photodarkened Waveguide and Grating Applications
Authors: Ramachandran S. , Bishop S. G.
Published: December 2022

Optical elements for applications in communications and interconnections such as waveguides and grating devices can be patterned in chalcogenide glasses by illumination with above band gap light, which causes photodarkening1. Photodarkening is a photo-induced red shift of the optical absorption edge and is accompanied by an increase in the index of refraction in the transparent spectral range below the absorption edge. A configurational model2 describes photodarkening as an illumination induced transformation from a stable configuration to a quasi-stable configuration via an electronically excited state. Annealing close to the glass transition temperature (Tg) causes a direct structural relaxation from the quasi-stable to stable state.
Long-period fiber-grating devices based on leaky cladding mode coupling
Authors: Stegall D. B. , Erdogan T.
Published: December 2022

Fiber gratings allow great flexibility in the design of all-fiber devices by enabling control over the wavelength, direction, polarization, and mode characteristics of light. In particular, long-period, or transmission, fiber gratings produce devices based on co-directional mode coupling which naturally result in a desirable transmissive rather than reflective output. In a single-mode fiber, coupling to cladding modes can be utilized for various functions, especially wavelength-dependent loss filtering [1]. In this paper we describe alternative applications of transmission fiber grating devices based on coupling to leaky cladding modes.
New Interferometer for Complete Design of UV-written Fibre Bragg Gratings
Authors: Fonjallaz P.-Y. , Sahlgren B. , Grennberg B. , Stubbe R.
Published: December 2022

Bragg gratings in optical fibres have been the subject of a very intense activity of research since the first demonstration of the side-writing technique with a UV laser by Meltz et al. in 19891. Since then, many improvements have been realised and other techniques have been developed. We present here a novel interferometer which allows a modification of the fringes period by changing only one parameter, the position of two mutually attached mirrors. This new system, in combination with the technique of writing long gratings by the superposition of subgratings while the fibre has an interferometrically controlled motion2, gives complete freedom for the design of gratings.
Short-wavelength, transmission-loss suppression in Fibre Bragg Gratings
Authors: Zervas Mikhail N. , Ibsen Morten , Laming Richard I.
Published: December 2022

Fibre Bragg Gratings (FBG’s) are known to suffer from short-wavelength, transmission losses due to resonant coupling into backward-propagating cladding modes [1,2]. Figure 1 shows a typical transmission spectrum of a 10cm standard FBG. The cladding mode losses increase with grating reflectivity and could eventually impose severe limitations in the use of FBG’s. The problem can be quite acute in the case that FBG wavelength-multiplexing is required. So far, several attempts have been made to eliminate the short-wavelength, transmission losses and improve grating performance [2-5]. In all cases, the resonant coupling of the forward-propagating core mode to the backward-propagating cladding modes is minimised by reducing the coupling strength.
Non-reflecting narrow-band fiber optical Fabry-Perot transmission filter
Authors: Johlen Dietmar , Klose Peter , Ewald Andreas , Brinkmeyer Ernst
Published: December 2022

Tilted Bragg gratings have been used for intermodal conversion in dual-mode fibers [1]. In this paper we demonstrate that such gratings in combined single-mode/dual mode structures are attractive for optical filter design. In particular, this concept is used here to realize narrowband Fabry-Perot transmission filters which - unlike ordinary FP-resonators - do not reflect the incident light at either side of the transmission peak.
Annealing of Long Period Gratings in Standard Hydrogen-Loaded Fiber
Authors: Bakhti F. , Larrey J. , Sansonetti P.
Published: December 2022

Long period gratings (LPG) are commonly fabricated in hydrogen-loaded fibers [1]. As classical Fiber Bragg Gratings (FBGs), LPGs have to be annealed at elevated temperature to stabilize their spectral response. Since a LPG of period λ is coupling the propagating mode with cladding modes (in this paper we focuse on LP01-LP05 coupling), the grating central wavelength λC is varying with the difference of effective indices between the two coupled modes, Δneff, by λC=Δneff Λ. As a consequence, a variation of 2 10-6 on Δneff will induce a variation of about 1nm on λC whereas for FBG, this kind of index variation has negligible effect. Taking into account the specification of the coupling induced by the LPG, we studied its thermal annealing during a long period of time (more than 100 hours) to observe index modulation change in the order of 10-6. In this paper, we present investigations on thermal annealing of LPG at temperature ranging from 110°C to 250°C, and with duration greater than 200h.
Fiber Grating Devices for WDM Communication Systems
Authors: Strasser Thomas A.
Published: December 2022

UV-induced fiber phase gratings [1,2] have become a very active area of research and development in recent years. This interest is in large part due to properties of these devices which make them an enabling technology for numerous high-performance devices. Perhaps the broadest range of devices developed to date is for fiber communications technology, where current and future devices will undoubtedly play a major role in implementing Wavelength Division Multiplexing (WDM) systems, as well as future, complex, optical networks based on such systems.
An All-Fiber, Zero Insertion Loss, Add/Drop Filter for Wavelength Division Multiplexing
Authors: Kewitsch Anthony S. , Rakuljic George A. , Willems Phil A. , Yariv Amnon
Published: December 2022

Numerous optical filter concepts have been proposed for dense wavelength division multiplexing (WDM) applications.(1-7) For the lowest insertion loss and most reliably packaged device, an all-fiber solution is preferred. The present filter is based on grating assisted mode conversion and backwards coupling in the merged region of two dissimilar waveguides formed by adiabatically tapering and strongly fusing two single-mode optical fibers. From the theory of adiabatic following,(8) the modes of the input fibers will evolve on a one-to-one basis into the first two eigenmodes of the merged region. These eigenmodes will propagate through the waist independently of one another, transform back into their original modes, and exit the device through their respective output fibers. This adiabatic mode evolution is lossless and free of optical crosstalk.
Low Crosstalk Optical Add-Drop Multiplexer based on a Planar Silica-on-Silicon Mach-Zehnder Interferometer with UV-induced Bragg Gratings and UV-Trimming.
Authors: Jouanno J.-M. , Zauner D. , Svalgaard M. , Kristensen M.
Published: December 2022

Optical Add-Drop Multiplexers (OADM) are key-components of multi-wavelength optical networks. Several techniques and designs may be used in order to achieve this function [1]. UV-induced Bragg gratings are of great interest since they enable construction of compact devices, and when written in the arms of a planar Mach-Zehnder interferometer they realise an OADM device with potentially low crosstalk. Moreover this device drops one channel without altering the other ones enabling cascading of several OADM's. Silica-on-Silicon planar OADM devices based on Mach-Zehnder interferometers have already been reported by other groups [2-5] but they were all limited by a low grating strength leading to a ratio between the -30 dB bandwidth in transmission and the -20 dB bandwidth in reflection, the so-called Bandwidth Utilisation parameter (BWU) [6], equal to zero and therefore a high intra-channel crosstalk. We present in this paper a planar OADM with a positive BWU obtained by writing strong gratings in waveguides [7].
Application of photosensitivity in planar silica-on-silicon optical waveguides
Authors: Hibino Yoshinori
Published: December 2022

Planar lightwave circuit (PLC) devices such as splitters, Mach-Zehnder interferometers and arrayed-waveguide grating (AWG) multiplexers, have been developed using GeO2-SiO2 waveguides on Si substrates. Such devices typically have low propagation and fiber-connection losses. Advanced optical communication systems, such as wavelength division multiplexing (WDM) systems, optical switching systems, and optical access networks[1] uses PLC devices. These silica-based planar waveguides are photosensitive[2]. This property can be used to make new types of PLC devices. For instance, photo-induced refractive index changes have been used for trimming the spectral response in the PLCs and forming Bragg gratings in the same way as used for optical fibers [3].
Self-writing in photosensitive materials: theory and experiment
Authors: Monro Tanya M. , Moss D. , de Sterke C. Martijn , Poladian L.
Published: December 2022

Theoretical models predict that a channel waveguide can be self-written in a planar photosensitive material using a beam of light.1,2 We present here the first experimental observation consistent with this self-writing process in germano-silicate glass, and de scribe the theoretical analysis of the process.
An Ion Exchange Model for Extended-Duration Thermal Poling of Bulk Fused Silica
Authors: Alley Thomas G. , Myers Richard A. , Brueck S. R. J.
Published: December 2022

Thermal poling induces a strong second-order nonlinearity in bulk fused silica.1 The non-linearity occurs on the anode side of the poled glass; various measurements have shown that the nonlinear region is ~ 5 to 15 μm thick; and that the nonlinearity scales linearly with the applied poling voltage. The formation of the nonlinearity is a dynamic process involving mobile ionic charge carriers.2 We present experimental observations of additional aspects of this dynamic process along with a model that demonstrates that ion exchange can play a role in the formation of the nonlinearity.
Absolute Prism-Assisted Maker Fringe Measurements of the Nonlinear Profile in Thermally Poled Silica
Authors: Pureur D. , Liu A. C. , Digonnet M. J. F. , Kino G. S.
Published: December 2022

Since the first measurements of a sizeable nonlinearity in thermally poled silica [1] were reported, there has been considerable interest in developing silica-based frequency converters and electrooptic devices. It is generally well accepted that the nonlinearity in thermally poled silica is confined to a thin (1-15 μm) layer on the glass sample that was exposed to the anode side during poling. However, reports differ markedly as to the shape (exponential [1], or Gaussian [2]) and thickness (a few to 10 μm and even 700 μm) [1-3] of this nonlinear region. In practical waveguide devices, a precise knowledge of these parameters is critical to understand and maximize the spatial overlap between this region and the optical mode. Yet to date, no standard method is available to measure these quantities reliably. Earlier, we made initial measurements of the nonlinearity using a prism pair [4]. Difficulties with the homogeneity of the poled region limited the maximum angle that could be explored, and a profile could not be definitively inferred. In this paper we describe 1) improvements in this prism-assisted Maker fringe technique and 2) a theoretical analysis that permits the first absolute measurement of the nonlinearity profile in poled silica.
Seeding and all-optical patterning of polymers
Authors: Nunzi J.-M. , Fiorini C. , Etilé A.-C. , Raimond P. , Charra F.
Published: December 2022

A key issue in the field of nonlinear optical polymers for second-order process is the achievement of a non-centrosymetric order. One challenging prospect is to achieve it by optical means in order to take full advantage of its rich processing capabilities. Indeed, the all-optical poling of polymers offers an interesting alternative to the realization of non-centrosymmetric structures. Of particular interest is the possibility to control extensively the spatial and tensorial properties of polymers using optical beams.
1
Defects Associated with Photosensitivity in GeO2-SiO2 Glasses
Authors: HOSONO Hideo
Published: December 2022

An absorption band centered at ~ 5eV in SiO2:GeO2 glasses is composed of two components, photobleachable and unbleachable ( by one photon process) components, and attributed the former and the latter to a neutral oxygen monovacancy ( NOMV ) coordinated with two Ge4+ ions and a Ge2+ ( this may be regarded as neutral oxygen divacancy, NODV ) coordinated with two oxygens, respectively. The NOMV is converted into a Ge E’ center by illumination with 5 eV light or with 488nm Ar laser light. On the other hand, NODV with a lone pair electron occupying the uppermost level emits an intense blue luminescence but does not change chemically with 5 ev-light (at least via one photon process ). Therefore, we consider that the presence of the NOMV is essential to emergence of index change by irradiation with488 Ar laser light. Concentrations of the NOMV and NODV and are 2xl016 and 2x1018 cm-3 in VAD-5GeO2-95SiO2 glasses ( as-delivered ) or 6x 1016 and 1 x 1018 cm-3 in 10GeO2-90SiO2 glasses, respectively.
Rise and Decay of 3.15 eV Luminescence in Germanosilicate Glass: Influence of Glass Densification
Authors: Dianov E. M. , Mashinsky V. M. , Neustruev V. B. , Sazhin O. D. , Sidorov V. A.
Published: December 2022

A wide variety of defects in germanosilicate glass observed in absorption and in luminescence spectra results in the energy transfer from some defects to others. Such a process was directly demonstrated by Gallagher and Osterberg1 and Bagratashvili et al.2 when 3.15 eV luminescence of germanium oxygen-deficient center (GODC) was excited by 5 eV photons. Along with usually observed decay of luminescence with about 100 µs lifetime they observed an initial rise of the luminescence with time of about 10 µs. To explain this phenomenon, Gallagher and Osterberg added to the commonly accepted scheme of GODC’s states (S0, S1 and T1) one more energy state of another defect. This state can nonradiatively transfer its excitation to the triplet state of GODC and this results in the rise of triplet-to-singlet luminescence. In this case the rate of the rise is governed by the lifetime of additional state.
Germanosilicate Glass Refractive Index Change Under Singlet and Triplet Excitation of Germanium Oxygen Deficient Centers
Authors: Dianov E.M. , Vasiliev S.A. , Frolov A.A. , Medvedkov O.I.
Published: December 2022

Although in-fiber photoinduced structures are widely used in practical applications [1] the nature and the microscopic mechanisms of glass photosensitivity is still unclear. To explain the phenomena observed in fibers under UV-irradiation, several models have been suggested: color center transformation [2], initial stress relief [3], UV-induced glass densification [4]. However these models are not in complete agreement with the experiments. It is well known that germanium oxygen deficient centers (GODCs) play an important role, at least at the initial stage of photoinduced glass transformation. As a rule, the intense GODC absorption band centered at 242 nm is used to write refractive index gratings in germanosilicate fibers.
Two Types of Photosensitivity Observed in Hollow Cathode PECVD Germanosilica Planar Waveguides.
Authors: Bazylenko M. V. , Moss D.
Published: December 2022

Plasma enhanced chemical vapour deposition (PECVD) is a promising technique for growing intrinsically UV-photosensitive germanosilica waveguides. Conventional PECVD techniques have been used to fabricate low-loss waveguide devices since the late 1980's [1], but it is only recently that work has started on the development of UV-photosensitive PECVD glasses for direct writing, bragg gratings and UV-tuning applications [2]. Although high intrinsic photosensitivity in conventional PECVD germanosilica has been reported [3], its practical use has been limited by the high loss of this material due to N-H related absorption and film porosity. The loss can be reduced by high temperature annealing which, however, deletes the intrinsic photosensitivity, thus negating its potential advantage of PECVD over the more mainstream, flamehydrolysis technique.
Photoinduced integrated optical devices in sulfide chalcogenide glasses
Authors: Viens J.-F. , Villeneuve A. , Galstian T. , Duguay M.A. , Cerqua-Richardson K.A. , Schwartz S.
Published: December 2022

Chalcogenide glasses are known to be optically highly transmitting in the 1-10 μm wavelength region and to have applications in both communication and mid-IR optical systems. Arsenic (S,Se)-based chalcogenide glasses also exhibit a wide variety of photostructural effects. Photostructural changes in amorphous chalcogenides are induced by exposing the material to near bandgap light. Such changes, among others, can be structural [1,2] (e.g. change in the density, photoexpansion) or optical [3] (e.g. photodarkening, refractive index change). Thin films of As-S-(Se) also exhibit photoinduced volume effects similar to those seen in bulk materials. This fact makes the application of the chalcogenide glass films to guided wave optical devices, very attractive. With suitable bandgap light exposure techniques, a variety of photoinduced integrated optical components can be patterned on thin films of chalcogenide glasses.
The nature of optically active defect centers in vitreous silicon dioxide.
Authors: Skuja Linards
Published: December 2022

Point defects are detrimental to the most applications which make use of the otherwise excellent optical and dielectric properties of vitreous SiO2. One notable exception to this rule is the writing of photoinduced gratings in SiO2:GeO2 glass fibers. There is ample evidence that the photosensitivity is connected to the presence of point defects in the glass, particularly, to the presence of the so called "oxygen deficiency centers" (ODC’s). While significant advances in optimizing the photoinduced grating writing have been made in recent years, the basic understanding of the underlying microscopic defect processes is still insufficient. The nature of a number of defect-related optical bands is still a matter of discussions. Most unsatisfactorily, the structure of the "key defect" to the fiber writing, the ODC, remains controversial.
Photosensitivity as it relates with glass macroproperties
Authors: Cardoso A.V.
Published: December 2022

Since Pelouze [1], it has been proposed that photosensitivity is a glass composition interacted property. Recent developments in Bragg grating technology have confirmed this analysis and indicated the importance of glass composition to improve glass photosensitivity as well as to measure the strength of the grating produced. Other important fact is the occurrence of high temperatures during the process of writing Bragg gratings which is usually mentioned in the literature.
UV-induced reaction of H2 with the core of germanosilicate and aluminosilicate fiber preforms
Authors: Dalle Caroline , Cordier Patrick , Depecker Christophe , Bernage Pascal , Douay Marc , Niay Pierre , Bayon Jean-François , Dong Liang
Published: December 2022

The photosensitivity of glasses can be significantly enhanced by high-pressure low-temperature hydrogen loading prior to UV exposure. The chemical reactions that occur between hydrogen and glass under UV exposure are thus of primary importance for the understanding of the mechanisms of H2 photosensitivity enhancement.
Spectroscopy and quantum efficiency of halide-modified gallium-lanthanum sulfide glasses doped with praseodymium
Authors: Hector J.R. , Wang J. , Brady D. , Kluth M. , Hewak D.W. , Brocklesby W.S. , Payne D.N.
Published: December 2022

Gallium-lanthanum sulfide (GLS) glasses are one of the most promising candidates for use in efficient 1.3 μm optical fiber amplifiers. In this paper we present a study of the optical properties of Pr3+-doped GLS, modified using alkali halides. It has previously been shown that the addition of halide modifiers to GLS has a beneficial effect on the glass- forming and bulk optical properties. In this paper we show that the optical emission properties of the Pr3+ dopants are altered by the addition of halide modifiers, but are still considerably better than either ZBLAN or oxide-modified GLS. The quantum efficiency of the 1G4-3H5 1.3 μm transition, which is the most important parameter for efficient amplification, has been measured at 55% for these glasses, compared to 65% in pure GLS. We will present studies of the effect of compositional changes on the Raman spectrum of the glass, and on the radiative and non- radiative decay of the Pr3+ ion, and show how these are related to changes in the structure of the glass.
Rare-earth-doped glass thin films for integrated photonics
Authors: Bruce Allan J.
Published: December 2022

Applications for which rare earth doped planar waveguide devices can be a viable alternative to fiber based devices will be considered. Erbium doped planar waveguide amplifiers for 1.5 micron amplification will be considered in detail and used to highlight issues of host material selection, luminescence quenching, codoping, waveguide design, fabrication, performance, integration and packaging.
Optical properties of gold (and other precious metals) in acetate glasses
Authors: Wilk N.R. , Schreiber H.D.
Published: December 2022

Colors of gold ruby glasses are variable, depending in part on the size of the gold particulates dispersed in the colloidal state. In order to understand more fully the optical properties due to Au and other precious metals (Ag, Pd, Rh, Ru, Re) in silicate glasses, this study reports on the inclusion of such metals into analogous, low-melting acetate liquids and glasses. For example, the color imparted by gold in Na-K-Ca-acetate glasses versus Li-Pb-acetate glasses changes from pink to purple, as the nature of the colloidal dispersion is affected by the structure of the acetate system. Other precious metals can be incorporated into the acetates as colloidal dispersions or as ions, with the resulting colors controlled by the nature of the metal and the structure of the acetate system.
40 dB Fiber Bragg Grating Written Through The Fiber Coating at 257 nm
Authors: Espindola R. P. , Atkins R. M. , Wang N. P. , Simoff D. A. , Paczkowski M. A. , Windeler R. S. , Brownlow D. L. , Shenk D. S. , Glodis P. A. , Strasser T. A. , DeMarco J. J. , Chandonnet P. J.
Published: December 2022

The writing of fiber Bragg gratings through the coating has important implications for the mass production of these devices. For instance, the time-consuming steps of stripping and recoating of the grating (potentially leading to fiber strength degradation), can be completely eliminated resulting in a simpler, more efficient and lower cost fabrication process. In the first demonstration of writing Bragg gratings through the coating, up to ~3 dB Bragg gratings were written through a UV-transparent acrylate-based 25 μm thick coating at 257 nm [1]. Subsequently, other researchers demonstrated a ~1 dB fiber Bragg grating written through a standard coating using 334 nm light [2]. Because the absorption band at 334 nm is much weaker than at 244 nm, these gratings required a very high germanium concentration (~20 mol%) and the addition of boron as a codopant to increase the photosensitivity of the fiber. The high level of germanium makes it difficult to achieve low-loss splices to standard communications grade fiber. Here we report for the first time highly reflective (99.99% Reflectivity, -40 dB transmission) Bragg gratings written through a novel polymer coating using a photosensitive germanium-doped fiber with 5 mole% germania.
Improved Efficiency Narrow-Band Acoustooptic Tunable Reflector using Fibre Bragg Grating
Authors: Liu W.F. , Dong L. , Reekie L. , Culverhouse D.O. , Russell P.St.J.
Published: December 2022

All-fibre versions of bulk devices are very attractive in fibre systems where low insertion loss is always desirable. We have greatly improved the performance of a recently reported [1] Bragg-grating-based acousto-optic superiattice modulator (AOSLM) by reducing the fibre diameter by HF etching. This improves the overlap of acoustic and optical power, resulting in modulator efficiencies as high as 90%. The modulator produces narrow-band amplitude-adjustable reflections that can be tuned over several nm, which is attractive for WDM and laser applications. In the device, an extensional acoustic wave is launched along a fibre Bragg grating. The ensuing superiattice modulation causes additional bands of reflection to appear on both sides of the Bragg condition. The device works by coupling together the forward and backward propagating Bloch modes in the grating (a principle first proposed in 1986 [2,3]) and operates in reflection mode. This differentiates the AOSLM from all previously reported acousto-optic fibre devices, which all rely on intermodal coupling, examples being LP01 to LP11 coupling in dual-mode [4] and twin-core [5] fibres, four-port null-couplers [6], polarisation mode couplers in Hi-Bi fibre [7] and guided-to-cladding mode coupling in standard telecom fibre [8]. In all these devices the intermodal beat length L
B
= λ /(n1 – n2) at optical wavelength λ between two modes with phase indices n1, and n2 is matched by the acoustic wavelength v
s
/ f
s
where v
s
and f
s
are the acoustic phase velocity and frequency.
Experimental and theoretical study of the origin of the second-order nonlinearities induced in thermally poled glasses
Authors: Le Calvez A. , Freysz E. , Ducasse A.
Published: December 2022

To model the poling process, the glass is assimilated to a neutral "solid electrolyte". During the poling process, an electric voltage V0 is applied between the cathode and the anode respectively located at x=0 and x=L. The evolution of the ion concentrations is then described by a system of coupled equations containing the equations of diffusion for the different ionic species and Laplace's equation. Since in fused silica, at about 300°C, it is mainly sodium ions, which are mobile, the anions are assumed to be immobile1. According to these approximations and under usual poling conditions (T≈300°C, V0≈3kV), we computed the expression of the potential across the sample during the poling. On Figure 1, we have plotted the potential V(x), the charge distribution ρ(x) and the associated electric field E(x) for a typical silica sample. Since the screening distances di and d2 at the cathode and the anode are much smaller than the sample thickness, the electric field E(x)~V0/d2~108 V/m at the glass interfaces is very high.
Strong Bragg Gratings Induced with 248 nm Light in Buried Silicon Oxynitride Waveguides
Authors: Hübner Jörg , Wiesmann Dorothea , Germann Roland , Offrein Bert J. , Kristensen Martin
Published: December 2022

Highly temperature-stable, 33-dB Bragg gratings have been induced in germanium-free silicon oxynitride waveguides. A fringeless pre-exposure is necessary to photosensitize the deuterium-loaded samples.
Gas-in-Glass — A New Raman Gain Medium: Molecular Hydrogen in Solid Silica Optical Fibers
Authors: Stone J. , Chraplyvy A. R. , Burrus C. A.
Published: December 2022

We describe a new type of Raman gain medium; namely, molecular hydrogen held in a solid-silica,(1) low-loss optical fiber (gas-in-glass). This new medium combines the advantages of a silica fiber -- long interaction path, low loss, controllable dispersion and convenience in handling -- with the large Raman shift of H2 (4136 cm−1 in silica).
Acousto-Optic Tunable Filter Utilizing Birefringence Dispersion in CdS
Authors: Chang I. C. , Katzka P.
Published: December 2022

Electronically tunable spectral filters have been of considerable interest for optical sensor and signal processing applications. The device which could most closely provide this function has been the acousto-optic tunable filter (AOTF). The AOTF, using collinear [1] and noncollinear [2] interaction geometry have been developed that demonstrated wide tuning range, high spectral resolution and large angular apertures.
Converting automotive free-form reflectors into phase images for computer-generated holograms
Authors: Hiller Lukas T. , Wallaschek Jörg
Published: December 2022

An approach for converting automotive free-form reflectors into phase images is shown. The reflectors height profile is linked to local phase shifts of plane waves. The results are verified by comparing ray-tracing and wave-propagation simulations.
Determining Multi-Features Characterizations of the Colliding Plasmas via Time Integrated Broadband Emission Imaging: Conceptual Design
Authors: Al-Juboori Haider M.
Published: December 2022

The spatial, temporal, and semi-spectral imaging technique was developed for colliding plasma experiments in nanosecond-scale, which reveals 3D-slicing presentation of 2D-images with detailed information on atoms/ions distribution inside the stagnation layer, furthermore, the multi-view stereo algorithm, that reconstructs 3D geometry by using photo-consistency functions, was proposed which help give deep insight into complex dynamical features.
INTERFERE: A Unified Compression Framework for Digital Holography
Authors: Muhamad Raees K. , Birnbaum Tobias , Blinder David , Schretter Colas , Schelkens Peter
Published: December 2022

Large data-rates together with a variety of formats, incurred by digital holographic applications, pose barriers to storage, transmission and interoperability. A compres-sion solution designed for addressing these concerns is proposed.
Lightguide type optical see-through super multi-view near-eye display using digital micromirror device and LED array
Authors: Han Woongseob , Han Jiyun , Ju Yeon-Gyeong , Park Jae-Hyeung
Published: December 2022

We propose a lightguide type optical see-through super multi-view near-eye display using a digital micromirror device and LED array. Super multi-view images mitigate the vergence-accommodation conflict and the lightguide combiner contributes to the system compactness.
Rendering of Transparent Objects in Large-Scale Polygon-Based Computer Holography
Authors: Nishi Hirohito , Matsushima Kyoji
Published: December 2022

A novel method for rendering transparent objects in polygon-based computer holography. The method uses rotational transform to simulate field propagation inside objects. A full-parallax large-scale CGH is demonstrated to show validity of the method.
Hologram printer for freeform holographic optical elements
Authors: Jeon Hosung , Jung Minwoo , Park Moonsung , Heo Daerak , Shim Bonggu , Hahn Joonku
Published: December 2022

Holographic optical elements (HOEs) have the advantage to be implemented in thin film. Compared to conventional hologram printer with spatial light modulator, we introduce a novel freeform HOE printer with a mechanical approach.
Fast High Resolution In-line Phase Retrieval of Sparse Off-Axis Holograms
Authors: Orzó László , Kiss Márton Zsolt , Terbe Daniel , Zarándy Ákos
Published: December 2022

A modified version of the well-known Gerchberg-Saxton algorithm is introduced that in the case of sparse samples provides an extremely fast and accurate phase reconstruction utilizing the whole bandwidth of an off-axis hologram.
Widefield Ultrafast Transient Microscopy Enabled by Off-axis Holography
Authors: Hörmann Martin , Visentin Federico , Zanetta Andrea , Grancini Giulia , van Hulst Niek F. , Liebel Matz , Cerullo Giulio , Camargo Franco V. A.
Published: December 2022

Using off-axis holography, we create an all-optical lock-in camera capable of acquiring ultrafast transient images spanning 100×100 μm2. Combined with structured illumination, it enables us to study exciton diffusion around 100 diffraction-limited spots.
Anisoplanatic Aberration Control in Multiphoton Holographic Projections
Authors: Maddalena Laura , Keizers Hidde , Pozzi Paolo , Carroll Elizabeth
Published: December 2022

We propose a sensor-less adaptive optics approach to correct local aberrations in holograms used for two-photon stimulation. Our method showed intensity enhancement of about 60 % in holograms projected into fixed zebrafish tissue.
Computer generated hologram encryption using array of vortex beams
Authors: Shikder Allarakha , Nishchal Naveen K.
Published: December 2022

Holography-based image encryption techniques offer several benefits. Owing to said features, this paper demonstrates a method to encrypt and decrypt an orbital angular momentum holography using an array of such beams.
Numerical investigation of fast layer hologram calculation with compressing layer images and point-spread functions
Authors: Shiomi Harutaka , Shimobaba Tomoyoshi , Kakue Takashi , Ito Tomoyoshi
Published: December 2022

We propose a fast layer hologram calculation method from RGB-D images by compressing both layer images and point-spread functions using the wavelet transform and investigate the calculation speed and the reconstructed image quality through simulation.
Compact and highly stable multi-modal system for biological applications
Authors: Tayal Shilpa , Mehta Dalip Singh
Published: December 2022

We develop a highly stable and compact multi-modal system to obtain multi-fold information about the biological specimen. The total internal reflection fluorescence (TIRF) unit is designed and coupled with the common path interferometer.
Phase Image Classification using Compressed Measurements of Single-Pixel Digital Holography
Authors: Endo Yutaka
Published: December 2022

In this study, we demonstrate phase image classification directly using measurements of single-pixel digital holography (SPDH). We also propose joint optimization of spatial patterns of SPDH and a classifier to improve classification accuracy.
Fringe pattern defect identification using Kalman filter and machine learning
Authors: Pandey Dhruvam , Gannavarpu Rajshekhar
Published: December 2022

The article introduces a Kalman filter and naive Bayes classifier based machine learning model for defect identification in the noisy fringe pattern. The simulation results corroborate the performance of the proposed method.
Diatomic Detour Phase Metasurface for Polarization-Insensitive Complex Amplitude Holograms
Authors: Jang Junhyeok , Kim Changhyun , Lee Byoungho
Published: December 2022

We propose a diatomic metasurface that modulates continuous amplitude and phase based on the detour phase. The proposed meta-holograms operate polarization-independently and show improved image quality in noise.
Holographic optical engine (HolOE) with high usability for high-quality and high-stable beam shaping
Authors: Hayasaki Yoshio , Hasegawa Satoshi , Zhang Honghao , Nakamura Yuta , Kosugi Takefumi
Published: December 2022

The holographic optical engine that is composed of a spatial light modulator (SLM), image sensors, relay optics, and a control computer performs an optimization of a computer-generated hologram (CGH) in an optical system. The CGH that generates two- and three-dimensional focusing spots are optimized before or during laser processing. Therefore, this method can compensate for static imperfections and dynamic changes in the optical system.
Adaptive Gaussian Points for Faster and Better Computer-Generated Holograms
Authors: Fricke Sascha , Caspary Reinhard , Castillo Susana , Magnor Marcus
Published: December 2022

To achieve better quality and generation speed, we generate holograms from adaptively sized and placed points, modeled as 2D Gaussians. We compute them with a Rayleigh-Sommerfeld convolution directly in a compact, radially symmetric look-up table.
Quantitative phase imaging and on-chip nanoscopy for 3D imaging of liver sinusoidal endothelial cells
Authors: Butola Ankit , Coucheron David A. , Szafranska Karolina , Ahmad Azeem , Mao Hong , Tinguely Jean-Claude , McCourt Peter , Senthilkumaran Paramasivam , Mehta Dalip Singh , Agarwal Krishna , Ahluwalia Balpreet Singh
Published: December 2022

We present a highly spatially sensitive quantitative phase microscopy system integrated with on-chip nanoscopy to visualize 3D morphology of liver sinusoidal endothelial cells (LSECs). We used the system to obtain 3D morphology of LSEC by using chip-based nanoscopy for lateral super-resolution, and QPM for mapping nanoscale thickness.
Speckle reduction method for phase-only hologram generation by double amplitude freedom Gerchberg-Saxton algorithm
Authors: Liu Kexuan , He Zehao , Cao Liangcai
Published: December 2022

A double amplitude freedom Gerchberg-Saxton (GS-DAF) algorithm is proposed. The amplitude constraints in iterations are relaxed by both the combined amplitude constraint and the support constraint. Enhanced reconstructions with less speckle noise have been achieved.
Vectorial metasurface holography for encryption and dynamic display
Authors: Wan Weiping , Ye Sheng , Han Yue , Gong Qihuang , Li Yan
Published: December 2022

Through controlling the phase difference of two different polarization-dependent holographic images, an extra vectorial holography with flexible spatial polarization distribution is encrypted with high resolution and dynamically reconstructed in far field.
High-Performance Holographic Optical Fibre Switches Enabled by Deep Learning Neural Network
Authors: Wang Haozhi , Nie Jiewen , Huang Zhikun , Yang Haining
Published: December 2022

This paper demonstrated a deep learning neural network that can generate high-performance beam-steering holograms with a worst-case port isolation of >25 dB for any target output ports and attenuation levels in an optical fibre switch.
Face profile detection based on the fringe projection incoherent digital holography
Authors: Lin Yu-Chih , He Ssu-Chia , Huang Chung-Hsuan , Tu Han-Yen , Cheng Chau-Jern
Published: December 2022

We propose and demonstrate a novel 3D detection technique by using fringe projection incoherent digital holography (FPIDH). The quantitative 3D facial profile with absolute axis was demonstrated by FPIDH without complicated mechanical process.
Compact solid-state multi-focal display engine for near-eye applications
Authors: Gertnerts Ugis , Balode Sandra , Linina Elza , Narels Martiņs , Zabels Roberts , Osmanis Ilmars
Published: December 2022

In this work a concept of compact solid-state multi-focal display architecture has been developed. Based on modelling data validity has been proven. A footprint reduction by a factor of 3 was achieved.
Simulation of Reconstructed Image Quality for Designing Ideal Holographic Near-eye Display
Authors: Higashida Ryo , Miura Masato , Yamaguchi Yuta , Funabashi Nobuhiko , Aoshima Ken-ichi , Machida Kenji , Yamaguchi Masahiro
Published: December 2022

We assessed the image quality in holographic near-eye displays by faithfully simulating coherent image formation on the retinal plane and comparing the simulated results with those of incoherent imaging.
Full-color Holographic System featuring Three-Dimensional Significant Object Detection
Authors: Bu Jingwen , Zhao Yu , Huang Yuan , Wang Xue
Published: December 2022

We propose a three-dimensional significant object detection method to improve the quality of the reconstructed image in the full color holographic system. The feasibility of this method is verified from the numerical experiments.
Divide-and-Conquer in Time of Fast Fourier Transform Algorithm and Its Applications in Diffractive Optics
Authors: Hsu Wei-Feng
Published: December 2022

The paper presents a process: the Cooley-Tukey algorithm was separated such that the inner calculations were conducted by MATLAB fft2 and the outer calculations were conducted by our codes. Its optical applications are also introduced.
Volume holographic Airy beam shaper
Authors: Hsu Hung-Chuan , Vyas Sunil , Huang Kuang-Yuh , Liao Hsien-Shun , Luo Yuan
Published: December 2022

Utilizing the photopolymer based volume-holography phase grating, a cubic-phase optical element is fabricated for the generation of 1D and 2D Airy beams. The characteristic properties of the generated Airy beams are experimentally verified and discussed.
Temporal Heterodyne Frequency Modulated Continuous Wave Digital Holography with Time-of-Flight Camera
Authors: Hammond Cole , Mohan R. Krishna , Babbitt WM Randall
Published: December 2022

We demonstrate an on-axis range selective temporal heterodyne digital holographic system, for both image plane and pupil plane geometries, using a frequency modulated continuous wave chirp and Time-of-flight camera.
Caustic Interpretation and Engineering of the Synthesized Vortex Beams
Authors: Xiao Na , Xie Chen , Courvoisier François , Hu Minglie
Published: December 2022

We propose an effective scheme to interpret and engineer the caustics of the synthesized vortex beams which would be beneficial to a broad range of applications such as particle trapping and micromachining.
Optical sectioning microscopy using diffractive optical elements
Authors: Luo Yuan
Published: December 2022

Metasurfaces have demonstrated their ability to replace large refractive optical elements. In this talk, I will discuss in the detail recent applications of metalens in two optical sectioning microscopy modalities.
Holographic optical element (HOE) recording technique for see-through AR-NED display using holographic printing
Authors: Dashdavaa Erkhembaatar , Imtiaz Shariar Md. , Hossain Md. Biddut , Wu Hui-Ying , Kang Hoonjong , Jeong Jong-Rae , Kim Nam
Published: December 2022

Holographic optical element (HOE) recording technique using holographic printing is presented. Holographic printer has the potential to realize complex optical functions with high diffraction efficiency and provides wide field of view for augmented-reality near-eye display.
High-dimensional Stokes-space spatial beam analyzer
Authors: Dahl Daniel S. , Plöschner Martin , Mounaix Mickael , Fontaine Nicolas K. , Carpenter Joel
Published: December 2022

We demonstrate a device for measuring the generalized Stokes parameters of a six spatial mode beam. The device is a single-shot wavefront sensor measuring spatial complex amplitude and coherence without an external phase reference.
Sensitivity Improvement in the Measurement of Sound Pressure with Parallel Phase-Shifting Digital Holography by Time-Frequency Filtering
Authors: Hashimoto Sota , Takase Yuki , Inoue Tomoyoshi , Nishio Kenzo , Xia Peng , Rajput Sudheesh K. , Matoba Osamu , Awatsuji Yasuhiro
Published: December 2022

We propose a method for improving the sensitivity in measurement of sound pressure with parallel phase-shifting digital holography by time-frequency filtering. We succeeded in measuring of acoustic wave at 97.75 dB sound pressure level.
Accelerating PhysenNet by image prior
Authors: Li Siteng , Wang Fei , Situ Guohai
Published: December 2022

We implement image prior and lightweight convolution in our PhysenNet for phase retrieval. Our results show that better image can be reconstructed while significantly reducing the computation expenses and training time.
Applications of diffractive optical elements for biomedical imaging
Authors: Luo Yuan
Published: December 2022

Diffractive optical elements have already demonstrated their ability to replace bulky refractive optical elements. In this presentation, I will discuss the uses of metasurface optical elements in biomedical imaging, specifically two optical sectioning microscopy modalities.
Depth-resolved interferometric imaging utilizing a spatially quasi-incoherent light source
Authors: Dembele Vamara , Wahl Joel , Sjödahl Mikael , Ramser Kerstin
Published: December 2022

An interferometric technique that utilize a spatially quasi-incoherent light source to perform interferometric measurements involving diffusely scattering objects is presented. The proposed technique is demonstrated with settings that give a depth gate of 90 µm.
Range Selective Digital Holographic Imaging Using FMCW Lidar
Authors: Goodman Matthew A. , Mohan R. Krishna , Babbitt Wm. Randall
Published: December 2022

Integrating frequency modulated continuous wave lidar techniques into digital holographic imaging allows for high resolution range selective holography. This technique is presented, showing cancellation of obscurations as well as enhanced contrast in images of objects.
Iterative optical diffraction tomography with embedded regularization
Authors: Smith-Dryden Seth , Fan Shengli , Li Guifang , Saleh Bahaa
Published: December 2022

Total-variation regularization is applied at each iteration of an iterative framework for optical diffraction tomography. Numerical and experimental tests are performed using various highly scattering objects, and significant improvement in reconstruction SNR are demonstrated.