bluuebunny/crossref_metadata_2025 huggingface dataset:
Laser annealing of proton-exchanged LiNbO3 integrated-optic structures
Authors: Farina James D.
Published: February 2023

The exact characteristics of an integrated-optic circuit are difficult to predict because of the sensitivity of the waveguide parameters to slight variations in the fabrication process. Recently, the annealed proton-exchange (APE) process has been developed for LiNbO3 and LiTaO3 integrated-optic fabrication.1-5 The APE process has eased the fabrication constraints by allowing the fabricator to trim the entire circuit by annealing the device (in an oven) to achieve greater diffusion of the exchange ion. This process works quite well except that it is not possible to anneal localized regions of the circuit selectively.
Test devices for the calibration of Ti:LiNbO3 processing
Authors: Wooten Ed L. , Chang William S. C.
Published: February 2023

The design and optimization of guided-wave devices in LiNbO3 has been greatly enhanced by the use of numerical techniques in the calculation of optical guided modes, electric fields due to electrodes, and optical interactions in various devices. However, the agreement between theoretical and experimental device performance will remain qualitative until an accurate determination of the various input parameters, such as those describing the index profile, can be obtained. Most laboratories rely on computer modeling to design and optimize devices but lack the ability to calibrate the index profile produced by their specific fabrication processes.
Design and fabrication of an overlay mode-index waveguide lens with novel boundaries
Authors: Brazas John C. , McMullen James P. , Kohnke Glenn
Published: February 2023

Waveguide lenses are recognized as key components for signal processing and source collimation in integrated-optical systems. A mode-index-type waveguide lens is most similar in design to conventional bulk lenses, focusing by the curvature of the boundary between regions of differing refractive properties (i.e., effective refractive index N in waveguides), which can result from waveguide thickness differences.1,2
Modeling of arbitrarily shaped conductor-dielectric waveguides
Authors: Rubin Barry J.
Published: February 2023

A generalized procedure is presented for obtaining the propagation characteristics of waveguides having a shape defined by steps along the Cartesian axes. The conductor and dielectric regions that compose the structures may be lossy and/or anisotropic. Although we consider only two-dimensional (2D) examples here, the approach applies to three-dimensional (3D) waveguides and to any discontinuities that may be present. This guided-wave formulation is novel because it applies 2D basis functions to represent the 3D polarization current in the dielectric regions.
An Explicit Finite Difference Beam Propagation Method: Application to Semiconductor Rib Waveguide Analysis
Authors: Chung Youngchul , Dagli Nadir
Published: February 2023

Semiconductor rib waveguides are the most basic components for integrated optics. Hence, their modeling and analysis are essential for the successful realization of photonic integrated circuits. For this purpose the so called beam propagation method employing fast-Fourier-transform(FFT) has widely been used to analyze single , coupled, and branching rib waveguides[1][2]. We will refer to this technique as FFT-BPM from now on. The accuracy of FFT-BPM is well demonstrated in comparison with the results of other methods of analysis[3]. However, it is well known that very small propagating step sizes are required for the accurate FFT-BPM analysis of a waveguide with a rapidly varying index profile such as a semiconductor rib waveguide. Recently, D. Yevick et al[6][7] developed several efficient beam propagation techniques for the analysis of semiconductor rib waveguides, which employ split step finite difference algorithm or direct multiplications by block-diagonal matrices for homogeneous propagation operator. In this paper, a new and very efficient BPM, abbreviated as EFD-BPM, is described. EFD-BPM utilizes an explicit finite difference algorithm, where partial derivatives in the paraxial wave equation are approximated using finite differences. This new method is applied to the analysis of single, coupled, and Y-junction semiconductor rib waveguides to demonstrate its accuracy and efficiency.
Comparison of various numerical methods for ridge waveguides
Authors: Khan M. Nisa , Piyaket Ram , Gopinath Anand
Published: February 2023

The four modeling techniques compared for the eigenmode analysis of optical ridge guides are effective-index, finite-difference semivectorial, finite-element semivectorial, and vector-H formulation methods. We have written software for the effective-index and finite-difference semivectorial and Rahman and Davies’ finite-element vector-H formulation techniques. Comparison of these methods are made by applying them to a single three-layer ridge guide with variable ridge height and outer slab thickness. The eigenvalue solutions from these methods yield the propagating modes and the normalized refractive indices for the various waveguide structures. Our results compare quite favorably with those of Stem and of Rahman and Davies.
Analysis of a novel rib-waveguide wavelength filter by the spectral-index method
Authors: Burke Susan V.
Published: February 2023

The application of the spectral-index (SI) method to analyzing the wavelength response of a filter consisting of two closely separated waveguides with ribs of different geometries is described. The modal indices (ns, nas) of the TE or TM lowest-order symmetric and antisymmetric-like supermodes are obtained from a single dispersion equation.1 The SI method is a fully two-dimensional modeling technique, previously established for single rib waveguides2 and symmetric couplers? that provides an accurate representation of the field profiles.
All-optical information processing in semiconductor multiple quantum-well or silica waveguide devices
Authors: Potasek M. J.
Published: February 2023

We show that novel solitons have properties particularly advantageous for optical information processing. Unlike the familiar solitons of the nonlinear Schrodinger (NLS) equation, we find that new solitons may be formed in both the normal and anomalous dispersion regions. This feature makes possible soliton behavior in a host of new materials including semiconductor multiple quantum-well, semiconductor-in-glass, or silica waveguides. In addition, these solitons maybe propagated by low-intensity lasers, such as semiconductor lasers. These new features can extend the usefulness of soliton behavior to optoelectronic or photonic integrated circuits. In particular, these solitons may be used for all-optical switching or optical computing.
Photorefractive instabilities in proton-exchanged waveguides: two-wave coupling and chaos
Authors: Sanford N. A. , Hickernell R. K. , Craig R. M.
Published: February 2023

Photorefractive two-wave coupling in LiNbO3 waveguides has been reported as an instability that couples orthogonally polarized TE and TM modes in either a Z-cut, Y-propagating orientation1 or an X-cut, Z-propagating orientation.2 We find that the throughput instability reported in Z-cut proton-exchanged Mg:LiNbO3 channel waveguides, which leads to severe instability in cw Cerenkov second-harmonic generation,3 is due to strong coupling between counterpropagating modes.
Simulation of pulse propagation in nonlinear distributed fiber filters
Authors: Kuo C. P. , Österberg U. , Stegemant G. I.
Published: February 2023

It has been shown that photoinduced phase gratings can be created in Ge-doped silica fiber core by using standard holographic recording techniques.1,2 Recently, it was suggested3 and shown experimentally4 that such fiber gratings have negative group-velocity dispersion (GVD) in the vicinity of the wavelength used to write the grating. Because this anomalous grating dispersion is orders of magnitude larger than the normal material dispersion of a glass fiber, an all-optical fiber pulse compressor in the visible wavelength would be achievable by combining the fiber’s self-focusing nonlinearity with the grating’s negative GVD. Because of the distributed feedback nature of the grating embedded fiber filter, a forward-propagating pulse will be coupled to the reflected pulse at all times, thus complicating the nonlinear interaction. In previous research3 pulse compression was predicted. However, it was not clear which parameters, besides the negative GVD, would affect the characteristics of a pulse during its propagation. The numerical simulation work in this paper shows the trade-off between parameters and establishes the limit on pulse compression.
Tailoring of hole band structure using biaxial strain for low-threshold, high modal purity multiquantum-well lasers
Authors: Loehr John P. , Bhattacharya Pallab K. , Singh Jasprit
Published: February 2023

In semiconductor lasers dramatic improvements in threshold current and high-temperature operation can be obtained if the valence-band density of states (and corresponding hole mass) is reduced.1-5 In most semiconductors (bulk and quantum wells) the hole density of states is fairly large; hence, under high-level injection the hole quasi-Fermi level is fairly close to the band edge, which makes the photon emission process somewhat inefficient. However, in coherently strained quantum wells (e.g. In
x
Ga1-
x
As/AlGaAs grown on GaAs or In0.53+
x
Ga0.47-
x
As/InP grown on InP) the hole band structure can be tailored to give a much lower density of states, resulting in a much more efficient photon emission for a given carrier injection. Using a 4 x 4 Hamiltonian to describe the valence-band structure, we calculate the modification of the hole dispersion relations in a variety of quantum-well structures. As can be seen in Fig. 1, a biaxial strain causes the hole masses (inverse curvature) to fall rapidly, which reduces the hole density of states by up to a factor of 3 near the band edges. Next we calculate the gain spectra for lattice-matched and strained quantum-well structures as a function of temperature. Typical results for the TE and TM mode material gain are shown as a function of carrier injection (for an example see Fig. 1) in Figs. 2 and 3.
Enhanced quantum-confined Stark effect in potential modified quantum-well structures
Authors: Ishikawa Takuya , Chan Yuen Chuen , Tada Kunio
Published: February 2023

Rectangular single quantum-well (QW) structures have been known for their large field-induced absorption coefficient variations, which are several magnitudes that of bulk materials. This is due to the well-known quantum-confined Stark effect (QCSE),1 which basically red shifts the fundamental exciton absorption edge quadratically with the electric field.
Analysis of a perpendicular waveguide cross containing a 45° gap at the intersection
Authors: Chu S. T. , Chaudhuri S. K.
Published: February 2023

The ability to make in miniature basic optical components is one of the most important factors in the development of intergrated optics circuit. Recently, fabrication of extremely compact components, such as beam splitters1 and zero-gap directional couplers,2 have been realized. These devices require interaction lengths of only a fraction of a millimeter to perform their required functions. The miniature beam splitter1 consists of two perpendicular AlGaAs/GaAs ridge waveguides, with a groove at the intersection. The groove was milled with a microfocused ion beam, and it was reported that the beam-splitting ratio could be adjusted by varying the groove depth. This device could be used as a power splitter or coupler or in the DFB laser circuit. The simple geometry permits easy integration, and a network of such structures may find application in optical computing. In this paper the beam-splitting characteristics of two perpendicular waveguides containing a 45° gap at the intersection, as shown in Fig. 1, are simulated by the FDTD method.3 Simulated results of the splitting ratio as functions of wavelength, gap width, and index change in the gap are presented.
Optimization of planar multilayer waveguide structures
Authors: Gobbi E. F. , Houde-Walter S. N.
Published: February 2023

The current trend in integrated optics and optoelectronics is toward more complicated structures. Analytic expressions and the numerical analysis of the physics of simple devices are indispensable for understanding the characteristics of a device. An analytic expression is also useful as a starting point in a design. However, the large number of effective degrees of freedom in a complex structure necessitate optimization routines to reach the best configuration.
Frequency doubling in planar KTP waveguides
Authors: Risk W. P.
Published: February 2023

Recent interest in compact sources of blue light using nonlinear frequency upconversion of infrared laser diodes has led to the investigation of waveguide frequency doublers. Second-harmonic generation has been achieved using Cerenkov phasematching1 and using quasi-phasematching in periodically-poled LiNbO3 waveguides2.
Highly dispersive InGaAlAs/lnP 3-mi wavelength-division demultiplexer
Authors: Croston I. R. , Young T. P. , Morasca S. , Rigo C. , Stano A.
Published: February 2023

Integrated-optical wavelength-division demultiplexers (WDDs) based on the two-mode interferometer have been demonstrated previously on semiconductors1 for which the principle of operation relies on interference between symmetric and antisymmetric waveguide modes. Here we report the first wavelength demultiplexer in InGaAlAs/lnP using the more dispersive interference between even-symmetry modes in a three-mode waveguide.
Soliton switching in optical fibers
Authors: Blow K. J.
Published: February 2023

Pulsed nonlinear-optical devices suffer from the well-known problem of pulse shaping when the response time of the nonlinearity is much shorter than the pulse duration. This situation will prevail in silica Tiber devices for pulses longer than 100 fs and has been observed in nonlinear couplers1 and in Sagnac interferometers.2 Solitons were first proposed as the solution to this generic problem3 in the context of Mach-Zehnder interferometers but have subsequently been applied to Sagnac interferometers4 and nonlinear couplers.5 All these devices are interferometric in the sense that two paths are available for the light propagation. The principle of soliton operation can be understood in terms of the effect of dispersion in these devices. When dispersive effects are unimportant, the device responds only to the instantaneous intensity of the pulse leading to the pulse being reshaped by the nonlinear device response. When dispersion is important, every part of the pulse is connected to every other part, leading to a collective behavior in which the phase shift induced at the peak of the pulse can be communicated to the wings. This is exactly the circumstance under which it is possible to form solitons. Therefore, perhaps it is not surprising that they turn out to be central to the successful operation and understanding of these nonlinear-optical devices.
Coupled-mode analysis of grating-assisted codirectional couplers
Authors: Huang Weiping , Lit John W. Y.
Published: February 2023

There has recently been interest in using grating-assisted couplers as wavelength-selective filters1,2 in integrated optoelectronics. A schematic diagram of the grating-assisted coupler is depicted in Fig. 1. Two dielectric waveguides are put in close proximity to permit coupling through the interaction of the evanescent fields of their guided modes. A set of gratings is placed with its axis parallel to the direction of wave propagation. The role of the periodic grating is to facilitate phase matching for the modes with different propagation constants so that efficient power exchange between the two guides can occur.
Nonlinear reflection of TM polarized plane waves and beams by a magneto-optic interface
Authors: Boardman A. D. , Kang Xie
Published: February 2023

The reflectivity of the TM wave from magneto-optic nonlinear interfaces between magnetized films of media like nickel, iron, or YIG bounded by a nonmagnetic, nonlinear substrate or cladding, or mixed with nonmagnetic, nonlinear films is calculated for the widely used1,2ATR configuration. The results mainly concern prism coupling but with the much less studied third-order nonlinear TM polarization3 being used. Progress toward extending the theory to include gratings is also discussed, however. Traditionally, magnetic-field orientations include transverse, polar, and longitudinal orientations, and these are the principal ones analyzed here. Longitudinal orientations involve some complex and novel nonlinear calculations because in such a case, even in the linear limit, TM and TE polarizations cannot be decoupled so that a linear Kerr rotation of the plane of polarization occurs. Questions concerning the optimum signal-to-noise ratio are addressed in order to try and arrange the highest value to coincide with the resonant angle positions. In this connection detailed comments on the trade-off between nonlinear and magneto-optic effects are given. Nonlinear ATR curves, the power flow along the surface, the first-order magneto-optical parameter, and the magnetic-field-induced rotation of the plane of polarization are all calculated for both plane waves and for finite beams with nonlocal nonlinearity. Again, because the latter is a difficult calculation to perform, the method alone is of great interest. The simpler transverse case can be cited as an example here. The ATR curves, as might be expected, break into branches at critical power levels, but this now feeds through into the relative change of the reflected intensity of light owing to the magnetization of the film. Any sharp decrease in this first-order magneto-optic quantity is now delayed by the nonlinearity, and a critical light intensity causes two or more branches to appear. For this same case we show that the forward field reflectivity actually switches to a second branch a little earlier than for the reverse field direction; hence, the resonance angles are not matched. Finally, comments on the exploitation of nonlinear magneto-optic effects in thin-film guided-wave geometries are included.
CAD – Layout for integrated-optical circuits
Authors: Wulf H. , Voges E.
Published: February 2023

The fabrication of integrated-optical devices (IOCs) requires, in the same way as in microelectronics, the cycle layout/simulation/manufacturing test. To avoid the production of a large series of IOC test structures, computer-aided technology (CAT) layout techniques are required. Because of the complex geometry of IOCs, even basic elements must be designed numerically; simple placement techniques of rectangular areas, as in microelectronics, are not sufficient. Basic requirements for IOC layout are, e.g., a variable length/width scaling, the inclusion of technological parameters as attributes, the verification of design rules and data interfaces to simulation programs. Various techniques for the numerical simulation and modeling of IOCs already exist1 as well as dedicated IOC layout editors.2
Triple-core nonlinear couplers-amplification, switching, and chaos
Authors: Snyder A. W. , Mitchell D. J. , Chen Y.
Published: February 2023

Triple-core nonlinear couplers display three characteristics that are not present with two cores. Ideal switching occurs by placing parasitic cores in parallel with the original twin-core structure. Amplification is possible at arbitrarily low pump power even for touching cores. Chaotic power splitting can be exhibited for arbitrary input polarization.
Investigation of third-order optical nonlinearities in semiconductor/glass composites using integrated-optical directional couplers
Authors: Wood V. E. , Ridgway R. W. , Busch J. R. , Krak S. J.
Published: February 2023

For effective device design and for elucidation of underlying mechanisms, it is important to determine whether the input-intensity-dependent response of a nonlinear directional coupler1 (NLDC) is predominantly refractive or absorptive.2 This is readily determined under practical conditions by studying the response of asymmetric NLDCs. A propagating-beam model,3 including effects of saturation of both refractive and absorptive nonlinearities, shows (Fig. 1a) that for a NLDC less than one half beat length long with a higher mode index in the input guide (positive asymmetry), the coupling initially increases with increased input power. This is because the nonlinearity, taken as negative, drives the guides toward synchronism. For negative asymmetry, the coupling initially decreases. For a coupler with saturable nonlinear absorption, however, asymmetry has little effect [Fig. 1(b)].
Mach-Zehnder interferometer-type optical waveguide coupler with wavelength-insensitive coupling ratio
Authors: Jinguji Kaname , Takato Norio , Sugita Akio , Kawachi Masao
Published: February 2023

Directional 2×2 couplers with coupling ratio insensitive to wavelength are required for branching/combining optical signals in a wide wavelength region. Such wavelength-insensitive couplers (WINC) have been realized in a fiber-optic configuration by fusing two single-mode fibers with slightly different parameters to each other and tapering them together.1 However, this type of fiber-optic WINC configuration appears to have some limitations in terms of its reproducibility, productivity, and suitability to integration. A possible approach to overcome these problems is the use of waveguide technologies to form integrated-optic WINCs. This paper describes the novel design and fabrication of the waveguide WINCs by using high silica on Si technologies.2,3
New poling techniques for electro-optic polymer devices
Authors: Ashley Paul R. , Tumolillo Thomas A.
Published: February 2023

Much progress has been made in the development of electro-optic (EO) polymers for guided-wave device applications.1-4 Reported here are techniques that use the device electrodes directly for poling. A TE device is demonstrated in which surface electrodes were used to provide alignment parallel to the substrate surface requiring no ground plane. A novel TM device structure was also demonstrated in which a push-pull electrode was poled with counteraligned fields so that the signal field is coaligned, thus requiring only a single voltage source. This development permits polymeric devices the same advantages as LiNbO3.
New applications and improvements of the method of lines beam-propagation method
Authors: Gerdes J. , Pregla R.
Published: February 2023

In this paper we apply the beam-propagation method (BPM) based on the method of lines1 (MoL) to the three-dimensional analysis of longitudinal-varying waveguide structures by using a two-step propagation algorithm.2 Significant features of the MoL BPM are the inclusion of an inhomogeneous basic medium into the first algorithm step and the use of absorbing boundary conditions.
Recovery of second order optical nonlinearity in annealed proton-exchanged LiNbO3
Authors: Cao Xiaofan , Srivastava Ramakant , Ramaswamy Ramu V. , Natour Jamal
Published: February 2023

Proton-exchange in LiNbO3 is extremely attractive for fabricating guided wave photonic devices. Owing to their higher photorefractive damage threshold, proton-exchanged (PE) waveguides provide a distinct advantage over their Ti-indiffused counterparts for applications such as nonlinear frequency conversion. It has been reported that PE waveguides tend to exhibit lower electro-optic and second-harmonic coefficients.1,2 Since stable, low-loss waveguides with restored electro-optic coefficients can be obtained by annealing the proton-exchanged guides,2 it is expected that SHG coefficients can also be restored by annealing.
Refractive-index changes arising from boron and fluorine impurity induced disordering in optoelectronic integration
Authors: Hansen S. I. , Marsh J. H. , Roberts J. S. , Gwilliam R.
Published: February 2023

The technique of impurity induced disordering (IID) by using the neutral impurities boron and fluorine introduced by ion implantation has received much attention. As opposed to IID produced by diffusion, implantation by ion beams facilitates abrupt, localized regions in which disordering can be carried out. This permits good lateral and longitudinal control of the disordering process.
Extended-cavity operation of glass integrated-optic lasers: mode locking, Q-switching, and wavelength tuning
Authors: Sanford N. A. , Malone K. J. , Larson D. R.
Published: February 2023

Rare-earth doping of integrated-optic devices fabricated in glass offers the simultaneous incorporation of active and passive components into a material system formerly regarded as being only passive. Previously,1 we described the operation of optically pumped channel waveguide lasers formed in Nd-doped silicate glass. In those experiments and in the present work the guides were made by k↔Na electric-field-assisted ion exchange. Other reports have appeared describing similar devices made by flame hydrolysis deposition and subsequent consolidation of Nd-doped silica soot.2 Waveguide lasers were also made by electric-field-assisted ion exchange from Ag films coated directly on Nd-doped glass.3 In this paper we demonstrate that Nd-doped integrated-optic waveguides can be used as gain elements in extended-cavity mode-locked or Q-switched lasers. Additionally, when using a grating as a feedback element, a cw extended-cavity laser was continuously tuned over 24 nm with a significantly narrowed line.
Wave packets in a semiconductor superlattice
Authors: Biermann Mark L. , Stroud C. R.
Published: February 2023

When a short laser pulse excites a quantum system, a spatially localized wave packet is formed.1 In this paper, we present a theoretical study of hole wave packets in a room temperature semiconductor superlattice, the unit cell of which consists of four layers. The first and third layers are GaAs wells of width 9 and 14 monolayers, 25.4 and 39.6 A. The second and fourth are 5 monolayers, 14.1-Å thick Al0.3Ga0.7As barriers. Effectively, the material is a series of coupled quantum wells of alternating thicknesses. These parameters give an even splitting between the first three hole states. The bandgap discontinuity is split, with 43% allotted to the valence band, and the growth direction is 100. The theoretical model is a k.p. local pseudopotential method based on that of Smith and Mailhiot.2
Numerical synthesis of optical waveguides by a random sampling method
Authors: Asakawa Shuichiro , Kokubun Yasuo
Published: February 2023

We have developed a novel method to search an optimum structure of optical waveguide satisfying required characteristics. This method consists of the combination of waveguide analysis and parameter sampling by using random numbers.
Analysis of a nonlinear directional coupler by a full vectorial finite-element method
Authors: Zoboli M. , Di Pasquale F. , Bassi P. , Tartarini G.
Published: February 2023

The nonlinear directional coupler is one of the most promising-all-optical switch devices as it has two input and output channels. This device has been analyzed both by means of the coupled mode theory and by the beam propagation method.1 In this paper, in order to study also the case of nonlinearity with high variations in the index of refraction, we analyze it with a full vectorial finite-element based code.2
Narrow bandwidth polarization modulator using GaAs/AlGaAs quantum wells
Authors: Ranalli E. R. , Sonek G. J.
Published: February 2023

Narrow linewidth optical fibers which can be monolithically integrated with laser diodes and optical detectors are of fundamental importance in optical communications systems. We report here on the development of an integrated optic TE-TM polarization converter using GaAs/AlGaAs multiple quantum well (MQW) strip-loaded waveguides. The exceptionally large modal dispersion for these waveguides, at wavelengths approaching the heavy and light hole excitonic resonances, is responsible for producing a narrow device linewidth of ~0.6 nm at a wavelength of 870.5 nm. Cascaded with appropriate integrated optic polarizers, this device could form the basis for a narrow bandwidth optical filter,1 on a semiconductor substrate.
Polymeric electro-optic modulators
Authors: Haas David R. , Man Hong-Tai
Published: February 2023

Switching voltages of NLO-polymer based electro-optic modulators competitive with devices in conventional materials have been reported by several groups.1-6. We have fabricated and tested polymer based Mach-Zehnder modulators fabricated with mode sizes dose to those of 1.3 μm optical fiber. These devices were fabricated using reactive-ion etching to form buried rib structures. Initial testing has shown no photo-induced damage to the waveguides illuminated with either 15 mW of 1.3 μm or 0.4 mW of 830 nm light The measured half wave voltage is below 10 V.
New direction in beam propagation
Authors: Hermansson Björn
Published: February 2023

We demonstrate that an exponential of a sum of non-commuting operators can be approximated to arbitrary order by a product of exponentials of the individual operators, generating rapid and accurate electric field beam propagation algorithms.
Need for integrated photonics in optical communications systems
Authors: Arthurs E. , Goodman M. S.
Published: February 2023

We present possible applications of integrated photonics devices to enhance the functionality and performance of optical communications systems and networks. Applications discussed include transmission, switching loop access for public networks, and signal processing. We provide target parameters for interesting system experiments.
Anisotropic reactive ion etching of InP in methane/hyclrogen based plasmas
Authors: McNabb J. W. , Craighead H. G. , Temkin H.
Published: February 2023

We have investigated reactive ion etching of InP in methane/hydrogen based plasmas. We have determined mask systems and etch chemistries for low roughness anisotropic etching of photonic device structures. Methane/hydrogen mixtures have been known to etch InP, however the simultaneous deposition of carbon containing polymer, surface roughness and lack of reliable rate control has limited their utility.1 We have carefully examined the role of etching conditions and chemistries to optimize the rate and anisotropy and to understand and control the polymer deposition in methane/hydrogen based etching. Part of the investigation included empirical modeling of the etch process.2 We have also studied the inclusion of oxygen in the etch gas for enhanced results.
Alignable epitaxial lift off GaAs materials using polyimide diaphragms
Authors: Camperi-Ginestet C. , Hargis M. , Jokerst N. , Allen M. , Drabik T.
Published: February 2023

The selective and alignable deposition of patterned, thin GaAs/GaAlAs based materials and devices onto host substrates such as Si, glass, lithium niobate, and polymers is important for the integration of GaAs with other material systems. We use a thin polyimide diaphragm as the transparent transfer medium for these thin patterned pieces of epitaxial material. Each of these devices or a group of devices is then optically aligned and selectively deposited onto the host substrate. This enables sparse distribution and frugal use of the costly GaAs material in addition to the alignable deposition of the devices, enhancing the manufacturing attractiveness of these thin epitaxial layers.
Reduction in bend loss of S-shaped dielectric slab waveguides
Authors: Yamauchi Junji , Ikegaya Morihiko , Nakano Hisamatsu
Published: February 2023

In integrated optics, S-shaped bends are indispensible for interconnecting different functional elements. To reduce bend loss, several methods have been proposed up to now. This paper reveals the effects of a combination of a trench section and an offset core on the bend loss. The calculation is performed using the beam-propagation method.
Analysis of crosstalk penalty in dense optical chip interconnects using single-mode waveguides
Authors: Li C.-S. , Olsen C. M.
Published: February 2023

It has been shown that passive waveguides based on silicon nitride1 or polyimide2 are suitable for very short distance interconnections, such as the interconnections between chips on a multi-chip module, a printed-circuit-board, or a backplane interconnections in a digital system. Although suffering more loss than fiber, passive waveguides have the potential of providing much closer spacing and planar crossover geometries, as well as integration of modulators, optical amplifiers, and receivers on the same substrate. The density of a waveguide array is mainly limited by the coupling induced crosstalk between adjacent waveguides. Waveguide coupling effects have been intensively studied3,4 but have not been related to the system requirements. In this paper, a crosstalk model is developed and used to analyze the system requirements for a passive waveguide array environment.
High-speed, low power optical modulator with adjustable chirp parameter
Authors: Korotky S. K. , Veselka J. J. , Kemmerer C. T. , Minford W. J. , Moser D. T. , Watson J. E. , Mattoe C. A. , Stoddard P. L.
Published: February 2023

Lithium niobate waveguide electrooptic modulators permit long fiber transmission spans with low dispersion penalty because of their capability for very low frequency chirp.1 It has been proposed that waveguide Mach-Zehnder amplitude modulators may be operated in a perfectly chirpless mode and devices designed to operate chirp-free have been reported.2−4 However, the lowest fiber dispersion penalty is generally not obtained for a frequency chirp parameter identically equal to zero. Indeed, choosing a non-zero value for the chirp parameter, α, depending on the fiber dispersion coefficient and distance, so as to provide some amount of pulse compression can be advantageous. Here we propose and report a Ti:LiNbO3 optical modulator that provides for complete adjustment of the modulation α-parameter. We demonstrate that this modulator can achieve virtually ideal amplitude or phase modulation, or any signed ratio thereof.
Optical and electronic properties of quantum wells
Authors: Schuurmans Martin F. H.
Published: February 2023

Semi-empirical electronic-band structure calculations have become a prominent part in the understanding and design of quantum-well lasers. This paper reviews semi-empirical k•p. calculations of confinement energy levels, optical transition strengths, spontaneous emission spectra and gain spectra of lasers, based on both unstrained GaAs/AlGaAs quantum wells as well as strained InGaAs/AlGaAs quantum wells.
Anomalous refractive-index change in proton-exchanged LiTaO3 optical waveguides after annealing
Authors: Yuhara Toshiya , Li Yu-Shan , Tada Kunio
Published: February 2023

Proton-exchanged LiTaO3waveguides have been reported to have attractive properties such as a highly preserved electro-optic coefficientγ33,1,2and lower susceptibility to optical damage than Ti-indiffused LiNbO3waveguides.2We have previously reported that an increase in the surface extraordinary refractive indices was observed after annealing3. We investigated this phenomenon in detail by using nuclear reaction and IR absorption spectra.
Controlled spontaneous emission in microcavity semiconductor lasers and LEDs
Authors: Björk Gunnar , Yamamoto Yoshihisa
Published: February 2023

Lasers with cavities with dimensions of the order of a wavelength will have such a large free-spectral range that they con only emit radiation into s single longitudinal mode only. By careful design, we can direct most of the emitted radiation into a single transverse mode. This is in sharp contrast to conventional lasers, which emit only one out of 104−105 spontaneous photons into the lasing mode. The high spontaneous emission efficiency of microcavity lasers may reduce the threshold current by several orders of magnitude from present devices. In this presentation we will clarify the conditions that must be met in order to do so. Also, a fundamental limit to lifetime shortening will be offered, and a novel, high-speed modulation technique for microcavity light emitting diodes will be presented.
17-GHz bandwidth SCH MQW 1.55-µm FP lasers
Authors: Lealman I. F. , Bagley M. , Cooper D. M. , Fletcher N. , Harlow M. , Perrin S. D. , Walling R. H. , Westbrook L. D.
Published: February 2023

Wide-bandwidth semiconductor lasers are essential components of both long-haul multigigabit intensity modulated systems and large-bandwidth analog systems that use subcarrier modulation. Many authors have reported wide-bandwidth bulk active devices in the InP/InGaAsP system.1-3 However, despite several authors suggesting that multiple quantum-well (MQW) lasers could provide larger bandwidths,4,5 few have been reported.6
Resonance-enhanced, low-voltage InGaAs avalanche photodiode
Authors: Campbell Joe C. , Kuchibhotla Ravi , Srinivasan Anand , Lei Chun , Deppe Dennis G. , He Yue Song , Streetman Ben G.
Published: February 2023

Avalanche photodiodes (APDs) and p-i-n photodiodes are two of the most widely deployed photodiodes for optical fiber communications. The transit time of photogenerated carriers in p-i-n diodes and that of secondary electrons in avalanche diodes at low gain is the fundamental limit on the bandwidth of these devices. However, conventional structures require a thick absorbing layer to ensure high quantum efficiency. Consequently, while high band widths of 35 GHz have been reported for In0.53Ga0.47As p-i-n photodiodes, the use of a 0.5-µm-thick absorbing layer restricted the quantum efficiency to ≤36%.1
Stimulated scattering of ultrashort pulses in birefringent fibers: numerical experiments
Authors: Trillo S. , Wabnitz S.
Published: February 2023

The modal structure of the optical field in fibers permits several phasematching mechanisms of four-photon scattering processes.1. We consider here the relevant case of mixing between the two orthogonally polarized linear modes of a birefringent fiber. Early and more recent experiments2-6 have demonstrated that the frequency conversion of picosecond pulses in biréfringent fibers is governed by the competition between parametric and Raman scattering.
Optimum soliton amplification through stimulated Raman scattering: a numerical analysis
Authors: De Angelis C. , Nalesso G. F. , Someda C. G.
Published: February 2023

It has been shown experimentally that solitons can propagate in optical fibers for thousands of kilometers when loss is compensated for by suitable amplification.1 As known, a possible amplification mechanism is stimulated Raman scattering (SRS). Various authors1-3 have used simple models for the nonlinear interaction between pump and soliton.
A 0.8 Numerical Aperture Two Element Objective Lens for the Optical Disk
Authors: Yamamoto Kenji , Osato Kiyoshi , Ichimura Isao , Maeda Fumisada , Watanabe Toshio
Published: February 2023

To improve the resolution of an optical pick-up, it is desirable to decrease the wavelength or to increase the numerical aperture (NA) because the spot size is determined by diffraction to be approximately λ/NA, where λ, is the free space wavelength. Recently, Kino and co-workers1 have demonstrated an increase in the effective NA of the objective by a factor of n, the index of refraction, in an optical microscope by using a hemispherical lens which has been called a solid immersion lens (SIL) placed between the focusing objective and the sample. Furthermore, they increased the NA of the optical pick-up in an optical disk system by placing a SIL very close to the disk substrate.2–4
Expected Market and Applications of DVD Products
Authors: Thagard Greg
Published: February 2023

DVD will create new synergies in what are diverse markets. Linear application will have new interactivity and interactive will have new user acceptance with better resolution and speed improvement.
Red Readable CD-R Media
Authors: Tyan Yuan-Sheng , Raychaudhuri Pranab , Pan Kee-Chuan , Olin George R. , Vazan Fridrich
Published: February 2023

Most successful recordable-CD media (CD-R) to date are based on a design suggested by Hamada et al(1). In this design the CD-R disc is constructed using a polycarbonate substrate, a lightly absorbing recording layer, and a gold reflector. The recording layer needs to have a unique set of optical properties: high n and low k. This is achieved currently by using the anomalous dispersion effect (Kramers-Kronig relation) in dyes having the trailing edge of absorption near the operating wavelength of 780 nm(2). Using this principle(3), most CD-R media today are based on two classes of dye, cyanine and phthalocyanine.
Small Size and Large Storage Capacity Optical Video Disk Recorder
Authors: Itoi S. , Matsui T. , Uchikawa T. , Miyatake M.
Published: February 2023

Small size and large storage capacity optical video disk recorder has been developed. The recorder has a memory capacity of 10.4 Gbytes for both sides of a 12cm
ϕ
phase change disk. It can record video signal compressed to 25Mbps in intra-frame fixed length coding, 2-channel audio signal, and user data. Specifications are shown in Table 1.
On Simplified Optical Disk Cluster Drive
Authors: Tanaka Kunimaro , Negishi Yoshinori , Yoshimoto Kyosuke , Takahashi Yasunori
Published: February 2023

Although hard disk drives are mostly used for cluster drives, optical disk cluster drive has advantage.[1] The removability of the disks can make cost per magabyte low. This characteristics is especially important for storing video data in video on demand system. This paper describes the simplification of structure of the optical disk cluster drive.
Write Algorithms for PWM Recording in MO Systems
Authors: Hurst Jerry
Published: February 2023

This talk will focus on advanced write algorithms for high density, high data rate optical recording in MO systems with special emphasis on optimizing overall system performance.
Dual Focus Optical Head with A Hologram-Integrated Lens
Authors: Komina Yoshiaki , Tanaka Yasuhiro , Urairi Kenichiro , Nishino Seiji , Mizuno Sadao
Published: February 2023

Development of a high density optical disk format named DVD was agreed upon last year (1995). The format adopts a 0.6 mm disk to simultaneously use a high numerical aperture (NA) lens and gain tolerance of disk tilt.1 Because of a Immense popularity of the CD format, it is important to playback the current, widely used Compact Discs (CDs) on the DVD format player. This requires an optical head that can read both conventional 1.2 mm disks and the new 0.6 mm disk. To read both disks with the same optical head, it is necessary to correct spherical aberration, which is caused by the difference in disk thickness.
The Importance of the Secure Hyper Storage Media in the Global Information Network
Authors: Yoshioka Makoto
Published: February 2023

This paper describes the importance of 3.5" magneto-optical media as the secure hyper storage technology in an information centric global network.
Photon-Excited Processes In Nonlinear Optical Materials
Authors: Rong Ailun , Lu Yanwu , Yuan Kaihua , Zhang Zhonglin , Shi Luqing
Published: February 2023

Traditional reversible order⟺disorder( O,DO ) transformations in recording media of optical memory (OM ) caused by pulsed infrared (IR) laser diode, 830nm, is mainly based on the thermal-induced phase-change (TPC ) processes shown as follows: The overall understanding of the mechanism of TPC OM and rewritable technology has increased steadily over the past few years, but some problems remain. The major unresolved problems are: ( 1 ) Thermal fatigue in recording layer, ( 2 ) Slow response (10~50 ns for recording a bit), and ( 3 ) Imperfection in theory — in which photon-excited processes have not been taken into account.
Long M-State Lifetime Bacteriorhodopsin Films as Optical Cache Memory Devices
Authors: Wang C. H. , Bacon M. , Kar A. K. , Wherrett B. S. , Baxter R. L.
Published: February 2023

Bacteriorhodopsin (BR) is a protein found in the purple membrane of the salt-loving bacterium, Halobacterium Salinarium. One of the unique properties of this material is a light-driven proton pumping process and the associated photocycle that enables the bacterium to convert light energy into chemical energy if the ambient oxygen level becomes too low for respiration [1]. The photocycle involves a number of intermediate states characterised by different lifetimes and different absorption spectra. There is just one deprotonised state in the photocycle; known as the M-state, it is the most stable of the photocycle intermediates and as a result of the deprotonisation its absorption spectrum is significantly blue-shifted from that of the ground (B) state [1]. The lifetime of the M-state is the order of 10 ms for aqueous BR solutions and the absorption peak wavelength is shifted from the original position of 568 nm for the B-state, to 412 nm.
The Structural Design of Dual-layer Read-Only Optical Disks
Authors: Yang Bor-Wen , Liu Jia-Reuy , Shieh Han-Ping D.
Published: February 2023

Volumetric optical disks increase the recording density by using multilayer as media where data are recorded in each layer of the multilayer stack[1]. In dual-layer ROM (Read-Only Memory) disk[2], the upper data layer was designed to be semi-reflective so that the readout beam could partially transmit to the total-reflective data layer. Besides, a spacer layer[3] with adequate thickness was used between two data layers to reduce the interlayer crosstalk.
Method for normalizing the write laser power of magneto-optical disk drives by using a calibration disk
Authors: Hara Shigeji , Yamada Fumiaki , Sasaki Shuji , Oishi Kan-ichi
Published: February 2023

Normalization of write laser power is important for facilitating the device independent use of optical disks in optical disk drives produced by different manufacturers. Saturation curves measured under various write conditions are well correlated in shape after being normalized by their average P80 value(1). P80 is defined as the laser power that causes a signal amplitude equal to 80% of the maximum amplitude of a saturation curve when 3T signals are recorded as a function of laser power. This shows the possibility of using the P80 of a calibration disk as a reference value for the laser power of optical disk drives.
Photochemical and Spectroscopic Properties of Naphtacenequinones. Candidates for 3D Optical Memory Devices
Authors: Angelutc A.A. , Chikisev A.Yu. , Koroteev N.I. , Magnitskii S.A. , Meshalkin Yu.P. , Ozheredov I.A. , Orzhancev S.Yu. , Shuhin V.V. , Sokolyuk N.T.
Published: February 2023

One of the most perspective ideas of 3D optical memory devices is
two-photon writing and fluorescence reading [1]. There are many criteria
of practical application of photochromic materials in optical information
storage systems. Photochromic material which is considered as a candidate
for such 3D optical memory devices should possess the following
properties: high speed of photoreactions, large two-photon cross section;
high fluorescence quantum yield of the B form, the relatively low quantum
yield of back (B->A) photochromic reaction, etc. The photochemical and
thermal stability of both photochromic forms (forms A and B) is necessary
condition for these materials to be suitable. The naphtacenequinones are
promising objects due to relatively high stability and high speed of
phototransformation [2]. We investigated 15 derivatives of
naphthacenequiones in toluene and different polymer matrices such as
polystyrene and polymethylmethacrylate.
Scanning Probe-Based Data Storage
Authors: Mamin H. J. , Terris B.D. , Ried R. , Rugar D. , Chui B.W. , Kenny T.W.
Published: February 2023

Alternative approaches to data storage based on proximal probe technologies have recently generated a considerable amount of interest. Their chief attraction is the ability to create marks ("write") and detect them ("read") on an extremely small scale, giving rise to potentially high areal densities. We have previously demonstrated one such technique based on the atomic force microscope (AFM) using topographic readback and thermomechanical writing.1,2 Initially external lasers were used for reading and writing, but advances in micromechanics are allowing for the integration of these capabilities, greatly simplifying the overall implementation. We have also demonstrated an approach based on a near-field optical technique using a flying solid immersion lens (SIL).3,4 Though this technique offers a more modest improvement in areal density, it does not suffer from the same data rate limitations inherent in scanning probe techniques.