By Topic

Quantum Electronics, IEEE Journal of

Issue 9 • Date Sept. 2010

Filter Results

Displaying Results 1 - 25 of 31
  • [Front cover]

    Page(s): C1
    Save to Project icon | Request Permissions | PDF file iconPDF (1742 KB)  
    Freely Available from IEEE
  • IEEE Journal of Quantum Electronics publication information

    Page(s): C2
    Save to Project icon | Request Permissions | PDF file iconPDF (37 KB)  
    Freely Available from IEEE
  • Table of contents

    Page(s): 1233 - 1234
    Save to Project icon | Request Permissions | PDF file iconPDF (43 KB)  
    Freely Available from IEEE
  • Introduction to the Feature Section on Optical MEMS and Nanophotonics

    Page(s): 1235 - 1236
    Save to Project icon | Request Permissions | PDF file iconPDF (47 KB)  
    Freely Available from IEEE
  • A Millimeter-Tunable-Range Microlens for Endoscopic Biomedical Imaging Applications

    Page(s): 1237 - 1244
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (11447 KB) |  | HTML iconHTML  

    We report an electrothermally-actuated microlens scanner that is suitable for biomedical imaging applications. The microlens has a large tunable range and a low driving voltage, and the lens is made of glass. The enabling device is a new electrothermal actuator design that is capable of large vertical actuation (~0.9 mm) on a 3 mm device footprint, with small lateral shift (<; 7 μm) and tilting (<; 0.38°) at less than 4-V. The design, fabrication and characterization of the actuator are presented. Imaging results by the assembled microlens are also demonstrated. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Broadband MEMS-Tunable High-Index-Contrast Subwavelength Grating Long-Wavelength VCSEL

    Page(s): 1245 - 1253
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5341 KB) |  | HTML iconHTML  

    A widely-tunable single-mode 1.3 μm vertical-cavity surface-emitting laser structure incorporating a microelectromechanical system-tunable high-index-contrast subwavelength grating (HCG) mirror is suggested and numerically investigated. A linear tuning range of 100 nm and a wavelength tuning efficiency of 0.203 are predicted. The large tuning range and efficiency are attributed to the incorporation of the tuning air gap as part of the optical cavity and to the use of a short cavity structure. The short cavity length can be achieved by employing a HCG design of which the reflection mechanism does not rely on resonant coupling. The absence of resonance coupling leads to a 0.59 λ-thick penetration depth of the HCG and enables to use a 0.25 λ-thick tuning air gap underneath the HCG. This considerably reduces the effective cavity length, leading to larger tuning range and efficiency. The basic properties of this new structure are analyzed, and shown to be explained by analytical expressions that are derived in the paper. In this context, the penetration depth of the HCG is introduced and shown to be an important characteristic length scale. Throughout the tuning wavelength range, strong single mode operation was maintained and uniform output power is expected. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Pre-Shaped Open Loop Drive of Electrothermal Micromirror by Continuous and Pulse Width Modulated Waveforms

    Page(s): 1254 - 1260
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2886 KB) |  | HTML iconHTML  

    Open loop drive is simple but it often leads to large nonlinearity. Closed loop drive can compensate nonlinearity but it increases system complexity and cost. This paper reports open loop drive methods that minimize nonlinearity by using special input waveforms. A procedure for open loop control of electrothermal micro-electro-mechanical systems is established and demonstrated by using a thermal bimorph based 1-D electrothermal micromirror. Constant linear velocity scan profile is achieved over 90% of the full scan range. Constant angular velocity scan of an electrothermal micromirror is achieved by continuous wave actuation over a ±4.5° range. A pulse width modulated (PWM) waveform that is equivalent to the continuous waveform is derived and experimentally verified. PWM based open loop control can significantly reduce hardware cost and size in case of micromirror array actuation. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Mechanical Construction of Semiconductor Band Gaps

    Page(s): 1261 - 1267
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5296 KB) |  | HTML iconHTML  

    Mechanical position is used to control the wavelength of light emission of semiconductor heterostructures. The heterostructures are coupled across a gap that varies with position to tune electron states in much the same manner that optical cavities can be coupled across a tunable reflectivity mirror to control photon states. In the experiments, a SixN/InP cantilever containing an InGaAs surface well collapses over another InGaAs quantum well. The spacing between the wells varies along the cantilever, such that the heterostructure band gap is determined by the mechanical bending of the cantilever. Photoluminescence measurements of the coupled 200°A surface wells show a wavelength shift of up to 22 nm. Associated theory shows that mechanical quantum coupling enables interband or intersubband devices with unprecedented spectral tuning ranges for gain or absorption. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Surface Tension and Concentration Measurement of Sub- {\mu} L Solution Using a Cantilever-Based Optical Gauging System

    Page(s): 1268 - 1274
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (737 KB) |  | HTML iconHTML  

    A cantilever sensor integrated with an on-tip micro spherical reflecting mirror (MSRM) exhibits a larger optical beam displacement than a conventional one, i.e., the system sensitivity/responsivity is enhanced. In this paper, it is employed as a surface tension and concentration gauge that only requires 0.5 μL of solution. The MSRM-integrated cantilever is first set above a sodium chloride-water droplet carried by a glass substrate, and then the droplet is moved up gradually. Once the cantilever is touched by the droplet, it is pulled and bent down as the droplet reshapes. The cantilever deformation amount is related to the surface tension of the solution, which increases with the molar concentration of sodium chloride. According to our experiments, the surface tension varies from 72.1 to 77.7 mN/m as the molar concentration of sodium chloride in water increases from 0 to 3.13 M. Therefore, by measuring the bending amount of the cantilever, the surface tension as well as the concentration of the NaCl-water solution can be determined. We also perform the experiments on the alcohol (ethanol)-water mixture, whose surface tension, conversely, reduces from 71.4 to 57.5 mN/m as the alcohol molar concentration increases from 0 to 0.81 M. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analog and Digital Deformable Diffractive Optics Actuated by Inter-Nanomagnet Forces

    Page(s): 1275 - 1287
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6518 KB) |  | HTML iconHTML  

    In this paper, we present a novel actuation technique of diffractive optics based on magnetic interaction forces, permitting a fine resolution tuning as well as a tuning in discrete steps. This actuation combines advantages of “analog” and “digital” tuning in conventional diffractive optics. The application of a magnetic field perpendicularly to the beams of a freestanding grating coated with magnetic material generates intermagnet forces causing these beams to deform slightly or to clump together. A theoretical analysis of the forces has been carried out, followed by actuation simulations in both linear and nonlinear regimes for different types of gratings, showing examples of exponential and parabolic chirp profiles in addition to beam clumping. In experiment, the diffraction patterns of distinct fabricated gratings have shown both a continuous shift and smear as well as a discrete change in the diffracted angles proving the concept of analog and digital tuning. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Microelectromechanical Configuration of an Optically Reconfigurable Gate Array

    Page(s): 1288 - 1294
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (9417 KB) |  | HTML iconHTML  

    This paper presents a proposal of a novel optically reconfigurable gate array architecture with a microelectromechanical system (MEMS) mirror array that allows high-speed reconfiguration by exploiting large-bandwidth optical connections between the MEMS mirror array and a programmable gate array. The MEMS mirror array is used as a holographic memory. Four configuration contexts can be programmed electrically and dynamically onto the MEMS mirror array as holographic memory information. The configuration procedure is executed by switching both a laser array and an MEMS mirror array. This experiment demonstrated a four-context 146 ns microelectromechanical configuration for a programmable gate array. Sub-microsecond configuration is attainable. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Simulation-Based Study of MEMS X-Ray Optics for Microanalysis

    Page(s): 1295 - 1300
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6844 KB) |  | HTML iconHTML  

    A new type of X-ray optics system based on microelectromechanical systems technologies is proposed for microanalysis. Side walls of micro pores made by silicon dry etching or X-ray lithography are used as X-ray mirrors. Ray-tracing simulations are constructed to estimate the performance of a planar X-ray optics system made of silicon and nickel. From simulations, we conclude that, with this type of optics, a fine focus on the order of <; 10 μm is possible and the intensity gain is 1000-7000 at Al Kα 1490 eV, compared to the case without this optical system. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • CMOS-MEMS Based Optical Electrostatic Phase Shifter Array With Low Driving Voltage and High Fill Factor

    Page(s): 1301 - 1308
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1745 KB) |  | HTML iconHTML  

    This work develops a novel 4 × 4 optical phase shifting micromirror array that achieves a λ/4 vertical displacement and makes the mirror peak-to-valley deformation within λ/10 (514 nm light source). Each individual micromirror pixel is controllable and driven by an electrostatic parallel plate actuator. The mirror reflective surface is an aluminum layer with a high optical reflectivity exceeding 90%. This device achieves a high fill factor of more than 90% without an additional flip-chip bonding process due to the parallel plate actuator and the hidden suspension beam structures. The phase shifter array is fabricated using the Taiwan Semiconductor Manufacturing Company (TSMC) 0.35 μm 2p4m CMOS process and post-CMOS process. An in-house post-process is utilized to reserve a 40 μm thick bulk-silicon under the 200 μm X 200 μm mirror. This eliminates mirror deformation from residual stress after the device is released. The micromirror demonstrates a vertical displacement of λ/4 at only 3 V and the resonant frequency is 3.6 kHz. Industry can use this phase-shifting micromirror array as a spatial light modulator in holographic data storage systems in the future. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optical Image Analysis of the Novel Ultra-Lightweight and High-Resolution MEMS X-Ray Optics

    Page(s): 1309 - 1312
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (540 KB) |  | HTML iconHTML  

    We have been developing novel microelectromechanical systems X-ray optics for future satellites. It can be ultra-lightweight and of high-resolution. For the first time, we fabricated a spherical test optics made of silicon. We used the dry etching and hot plastic deformation method. We conducted imaging tests to examine whether it can focus a parallel beam of light. Visible light was selected instead of X-rays because of the convenience of testing. The focusing was confirmed with a full-width at half-maximum focal size of 2 arcmin. Since the focus is affected by optical diffraction, a smaller focus can be expected in future X-ray imaging tests. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Tunable Fiber Laser Using a MEMS-Based in Plane Fabry-Pérot Filter

    Page(s): 1313 - 1319
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5033 KB) |  | HTML iconHTML  

    We propose a tunable erbium doped fiber laser based on a Fabry-Pérot (F-P) cavity tuned by an electrostatic actuator. The device is made of single crystalline silicon. The F-P cavity consists of two Bragg mirrors, one being displaced by a comb-drives actuator. The F-P cavity, grooves for optical fibers and electro-mechanical structure are fabricated by deep reactive ion etching on a 70 μm silicon on insulator wafer and are integrated in a ring fiber laser. The resulting tunable fiber laser has a tuning range of 35 nm in the C-band and a spectral width of less than 0.06 nm. The maximum applied voltage for full tuning of the laser is 37 V. The mechanical resonance frequency of the actuated mirror is 14.4 kHz allowing fast tuning of the laser. The maximum output power is 1.8 mW. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dependence of Threshold Current Density on the Waveguide Ridge Width in Quantum-Cascade Lasers

    Page(s): 1320 - 1326
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4446 KB) |  | HTML iconHTML  

    We make a systematic study to find the dependence of the threshold current density of a mid-infrared quantum-cascade laser on the waveguide ridge width. The optical and thermal parameters of the waveguide are calculated with a finite-element method, and gain is found from a self-consistent rate equation model with energy-balance. The results show the existence of an optimal ridge width that minimizes the threshold current density of the laser. The influence of the interface roughness parameters on laser performance is also discussed. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Injection Laser Wavelength-Dependent Timing Jitter Reduction of Gain-Switched Single-Mode VCSELs

    Page(s): 1327 - 1331
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (525 KB) |  | HTML iconHTML  

    We report the effect of an external injection laser wavelength on reducing the timing jitter of optical pulses generated from gain-switched single-mode 1.5-μm vertical cavity surface emitting lasers (VCSELs). Simultaneous timing jitter reduction, pulse width shortening, and spectral linewidth narrowing without any peak power penalty were observed when the injection laser wavelength was tuned near the spectral peak of the free-running VCSELs spectrum operating in a continuous wave mode. The timing jitter was reduced up to 40% of that without any injection. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Emission and Absorption Cross-Sections of Mg/Er-Codoped Near-Stoichiometric {\rm LiNbO}_{3} Crystals

    Page(s): 1332 - 1341
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4508 KB) |  | HTML iconHTML  

    Near-stoichiometric (NS) (Mg:) Er:LiNbO3 crystals were grown from melts ([Li2O]:[Nb2O5] = 1:1) containing 0.0/0.5, 0.5/0.5, and 1.0/0.5 mol%/mol% MgO/Er2O3. OH absorption study shows that the optical damage threshold Mg concentration of the Er/Mg-codoped NS crystal is just near 1.0 mol%. Polarized visible and near infrared, and unpolarized mid-infrared (2.7 μm, 4I11/24I13/2) emission spectra of Er3+ ion in these crystals were measured. From measured emission spectra, the emission and absorption cross-section spectra were calculated based upon McCumber theory, and compared with the data of congruent Er:LiNbO3 bulk material and/or Ti-diffused Er:LiNbO3 strip waveguide and the results obtained from the direct unpolarized optical absorption measurements. The 550, 980, and 1530 nm emission lifetimes were also measured, and compared with the Judd-Ofelt theoretical values and the measured values of the congruent material. The results show that the polarized absorption cross-section data derived from the emission spectra are comparable to the unpolarized cross-section data from direct absorption measurements. The emission and absorption cross-sections, their polarization dependences as well as the lifetime all change definitely as the crystal composition shifts from the congruent point to the near-stoichiometry. In the NS crystal, the Er3+ ion has smaller emission and absorption cross-sections, and longer lifetimes. In contrast, MgO codoping has less effect on the emission and absorption cross-sections, and lifetime. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Transition Radiation X-Ray Laser Based on Stimulated Processes at the Boundary Between Two Dielectric Media

    Page(s): 1342 - 1349
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1385 KB) |  | HTML iconHTML  

    This paper analyzes a model of a transition radiation laser based on stimulated emission induced by relativistic electrons crossing the boundary between two media of different dielectric properties. Interaction between the incident radiation and the electrons in this boundary region is taken into account. Phenomenological quantum electrodynamics is applied to derive analytical expressions for stimulated emission and absorption probabilities. Analogs of Einstein's coefficients for the transition processes have also been derived and discussed. It is shown that stimulated emission is greater than absorption. The gain is then calculated. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Measurement of Small-Signal Gain on COIL With Chemically Generated Molecular Iodine

    Page(s): 1350 - 1353
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1981 KB) |  | HTML iconHTML  

    A chemical gas-phase reaction between Cl2 and HI was used in the generation of molecular iodine for the chemical oxygen-iodine laser (COIL) operation. A yield of I2 in the generation reaction up to 85% was achieved in a reasonable volume of the reactor. A small-signal gain up to 0.75%/cm at a temperature of 150 K in the center of supersonic cavity was measured. A comparison with the established evaporation way of I2 delivery confirmed that the chemical method has little or no impact on the COIL pumping kinetics. This chemical method is easily scalable and can simplify the COIL operation by providing better control of I2 flow rate. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Synchronization and Relative Timing Jitter Measurement of Femtosecond and Picosecond Laser Regenerative Amplifiers

    Page(s): 1354 - 1359
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2326 KB) |  | HTML iconHTML  

    In this paper, precise synchronization of the femtosecond and picosecond laser regenerative amplifiers with different wavelengths and independent seed oscillators was achieved using the electronic phase-locked loop and global clock techniques. The root-mean-square relative timing jitter of the two regenerative amplifiers was measured as 0.66 ps using a modified statistical method based on the error propagation relation between the independent variables and the conventional optical cross-correlation technique. The results suggest that this method is more accurate and requires simple optical setups for low-pulse repetition rate lasers. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Impact of Losses in the Bragg Section on the Dynamics of Detuned Loaded DBR Lasers

    Page(s): 1360 - 1367
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3286 KB) |  | HTML iconHTML  

    The dynamics of a distributed Bragg reflector laser with optical losses in the Bragg section is studied in detail. It is found that the modulation response depends not only on the detuning of the lasing wavelength from the Bragg reflectivity peak but also on the magnitude of the waveguide losses in the Bragg section. Depending on the losses, the damping of the relaxation peak can either increase or decrease when the laser is detuned on the long wavelength flank of the Bragg peak. Hence, in order to achieve maximum modulation bandwidth of the laser, the laser needs not only to have the correct detuning but also an optimized waveguide loss in the Bragg section. The physical reason for this dependence is discussed in terms of a modified rate equation model. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fundamental and Dynamic Properties of Intermixed InGaAs-InGaAsP Quantum-Well Lasers

    Page(s): 1368 - 1374
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6501 KB) |  | HTML iconHTML  

    The fundamental and dynamic properties of InGaAs-InGaAsP lasers, where emission wavelengths were blue-shifted by quantum-well intermixing through ion implantation and annealing, were investigated to assess possible degradation by intermixing. It was found that the fundamental properties such as threshold current and slope efficiency were largely unchanged even after as much as 120 nm of wavelength shift. Meanwhile, the dynamic properties such as modulation efficiency and K factor were degraded after just a moderate degree of intermixing, but the degradation was not worsened by further intermixing. Provided the finite degradation of dynamic properties is tolerable, the present intermixing technique will be very useful for the fabrication of photonic integrated circuits. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Effects of Nanometer-Scale Photonic Crystal Structures on the Light Extraction From GaN Light-Emitting Diodes

    Page(s): 1375 - 1380
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3060 KB) |  | HTML iconHTML  

    This paper reports on the effect of nanometer-scale photonic crystal structures on the enhancement of the light extraction in GaN light-emitting diodes. Photonic crystals with hole or pillar-patterned structures with lattice constants of 460, 600, 750, and 920 nm are fabricated on indium-doped tin oxide (ITO) electrodes and/or p-GaN layers using laser holography and reactive ion etching. It is found that the light extraction efficiency depends strongly on the distance between the photonic crystal and the active layer, as well as the lattice constant for both structures. Photonic crystal light-emitting diodes (LEDs) with a lattice constant of 750 nm and hole depths of 260 nm in the ITO layer show an increase in light extraction of up to 32%, compared to conventional LEDs, without degradation in the electrical properties while a maximum enhancement of 26% is obtained from the device with a lattice constant of 460 nm and pillar heights of 60 nm on the p-GaN layer. The dependence of the extraction efficiency on the lattice constant is also calculated using a 3-D finite-difference time-domain method and compared with experimental results. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • InGaN/GaN White Light-Emitting Diodes Embedded With Europium Silicate Thin Film Phosphor

    Page(s): 1381 - 1387
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (4091 KB) |  | HTML iconHTML  

    This article describes the successful fabrication of europium-silicate thin film phosphor and its application to InGaN/GaN white light-emitting diodes (LEDs) in order to improve the photometric properties of the LEDs, including their correlated color temperatures (CCT) and color rendering index (CRI). The europium-silicate compounds are deposited on GaN templates grown on sapphire substrates by RF-sputtering and then annealed at 1000°C in an N2 ambient to form a thin film phosphor that produces yellow or red emissions. The thin film phosphor is then patterned with stripes to grow a GaN buffer layer by epitaxially laterally overgrown GaN (ELOG) techniques, on which LED structures are grown by metal organic chemical vapor deposition. The ELOG sample shows no pits on the surface, and the full widths at half maximum (FWHMs) of its X-ray rocking curve for the (002) and (102) planes are as low as 249 and 416 arcsec, respectively. The optical spectrum from the embedded thin film phosphor is adjusted to have a maximum intensity at 560-600 nm and a FWHM as wide as 90 nm to make up for the low efficiency at these wavelengths of conventional YAG-based yellow phosphor. Finally, we observed a tristimulus coordinate (x, y) = (0.33, 0.39), CCT = 5607 K, and CRI = 77.6 from the white LEDs with thin film phosphor as compared with (x, y) = (0.30, 0.28), CCT = 8467 K, and CRI = 66.52 for the white LEDs without thin film phosphor. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

The IEEE Journal of Quantum Electronics is dedicated to the publication of manuscripts reporting novel experimental or theoretical results in the broad field of the science and technology of quantum electronics..

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Aaron R. Hawkins
Brigham Young University