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Quantum Electronics, IEEE Journal of

Issue 2 • Date Feb. 2012

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Displaying Results 1 - 25 of 33
  • IEEE Journal of Quantum Electronics publication information

    Page(s): C2
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    Freely Available from IEEE
  • Table of contents

    Page(s): 81 - 82
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  • Special Issue: Optoelectronic Device Integration

    Page(s): 83 - 85
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  • Special Issue Dedication: James J. Coleman

    Page(s): 86
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  • Integrated Tunable Quantum-Dot Laser for Optical Coherence Tomography in the 1.7 \mu{\rm m} Wavelength Region

    Page(s): 87 - 98
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (938 KB) |  | HTML iconHTML  

    In this paper, we present the design and characterization of a monolithically integrated tunable laser for optical coherence tomography in medicine. This laser is the first monolithic photonic integrated circuit containing quantum-dot amplifiers, phase modulators, and passive components. We demonstrate electro-optical tuning capabilities over 60 nm between 1685 and 1745 nm, which is the largest tuning range demonstrated for an arrayed waveguide grating controlled tunable laser. Furthermore, it demonstrates that the active-passive integration technology designed for the 1550 nm telecom wavelength region can also be used in the 1600-1800 nm region. The tunable laser has a 0.11 nm effective linewidth and an approximately 0.1 mW output power. Scanning capabilities of the laser are demonstrated in a free space Michelson interferometer setup where the laser is scanned over the 60 nm in 4000 steps with a 500 Hz scan frequency. Switching between two wavelengths within this 60 nm range is demonstrated to be possible within 500 ns. View full abstract»

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  • Design and Experimental Evaluation of Active-Passive Integrated Microring Lasers: Noise Properties

    Page(s): 99 - 106
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    The phase and intensity noise of microring lasers coupled with passive waveguides are examined through linewidth and relative intensity noise measurements. Laser linewidth down to 500 KHz was measured through the self-homodyne technique and a direct association is established between the linewidth and the two main structural parameters of a microring, the ring radius and coupling efficiency with the bus waveguide. Coupling efficiency is estimated through waveguiding analysis by means of 3-D finite difference in time domain techniques. View full abstract»

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  • New Theoretical Model to Analyze Temperature Distribution and Influence of Thermal Transients of an SG-DBR Laser

    Page(s): 107 - 113
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB) |  | HTML iconHTML  

    A theoretical model capable of calculating transient temperature distribution and simulating the dynamic lasing behavior of a sampled grating distributed Bragg reflector (SG-DBR) tunable laser with the influence of thermal effects into account is described in this paper. Transient 3-D temperature distribution of an SG-DBR laser is modeled by numerically solving heat transfer equations using finite element method. Then, a temperature-dependent dynamic transfer matrix method based model of the laser is developed, which can take thermal effects into account. In this paper, we pay special attention to thermally induced wavelength drift and spectrum evolution under different combinations of tuning currents. Simulated results show that the wavelength drifts are usually in the order of several tens of picometers. Furthermore, when the tuning currents are switched to some certain values, thermal transients may cause mode hop or dual modes lasing. In these cases, total wavelength change induced by thermal effects can be as large as 0.6 nm. View full abstract»

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  • Theory and Design of THz Intracavity Gain-Flattened Filters for Monolithically Integrated Mode-Locked Lasers

    Page(s): 114 - 122
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    We present the theory and design of a tunable gain-flattening filter for integrated mode-locked lasers (MLLs). The filter provides the inverse of the semiconductor spectral gain profile and produces a broad flattened net gain. This improves the performance of MLLs by allowing more modes to lase simultaneously. We demonstrate a gain-flattened MLL with a record 10 dB bandwidth of 2.08 THz, the widest frequency comb span for an integrated quantum-well-based laser at 1.55 μm. Gain-flattening theory is used to extend the integrated comb span to 40 nm. We use scattering matrices to investigate feed-forward filters based on asymmetric Mach-Zehnder interferometers (MZIs). We compare MZI filters designed for a fixed coupling value to those that use an active gain arm to adjust the extinction ratio. Tunable zero placement of these filters is achieved using a passive phase tuning arm. The optimized gain-flattening filter has a 5 dB extinction ratio and a 70 nm free-spectral-range. When the filter is incorporated into a ring MLL, simulations predict a 40 nm, i.e., 5 THz, comb span with a power variation <; 3.5 dB. View full abstract»

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  • Lateral-Longitudinal Modes of High-Power Inhomogeneous Waveguide Lasers

    Page(s): 123 - 128
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    We present modeling results for lateral-longitudinal modes of longitudinally inhomogeneous finite-length waveguides of ridge semiconductor lasers generating high brightness emission. By numerical solution of the wave equation for a 2-D waveguide, including the output facet, and calculation of the lateral-longitudinal mode threshold (mode lifetime) we show that corrugations of the stripe boundaries along the longitudinal direction cause discrimination of the lateral modes in stripes which are typically wider than those supporting single lateral mode emission. This discrimination is due to higher scattering losses of the higher-order modes in the lateral direction as compared to the fundamental mode. Thus still for wide stripes the output radiation is expected to be single-mode resulting in a high-quality far field with narrow divergence in the lateral direction. Simultaneously, due to the wider stripe width the output emission might have higher power and therefore higher brightness operation can be achieved as compared to a straight stripe without corrugations. View full abstract»

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  • Semiconductor Ring Laser With On-Chip Filtered Optical Feedback for Discrete Wavelength Tuning

    Page(s): 129 - 136
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (833 KB) |  | HTML iconHTML  

    We introduce a novel concept of discretely tunable semiconductor lasers with on-chip filtered optical feedback. The integrated device is based on a semiconductor ring laser that can sustain two counter-propagating modes. By means of a directional coupler, part of the light emitted by the laser is coupled out to a feedback section integrated on the same chip. The feedback section contains two arrayed waveguide gratings and a set of semiconductor optical amplifiers to provide filtering of particular longitudinal modes sustained by the ring cavity. By controlling the current injected into the semiconductor optical amplifiers, single mode operation in both directions is achieved. In this paper, the design, characterization, and modeling of the device is presented. View full abstract»

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  • AlGaInAs/InP Monolithically Integrated DFB Laser Array

    Page(s): 137 - 143
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    The monolithic integration of four 1.50-μm range AlGaInAs/InP distributed feed-back lasers with a 4 × 1 multimode-interference optical combiner, a curved semiconductor optical amplifier and an electroabsorption modulator using relatively simple technologies-sidewall grating and quantum well intermixing-has been demonstrated. The four channels span the wavelength range of 1530-1566 nm and can operate separately or simultaneously. The epitaxial structure was designed to produce a far field pattern at the output waveguide facet, which is as small as 21.2°× 25.1°, producing a coupling efficiency with an angled-end single mode fiber at twice that of a conventional device design. View full abstract»

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  • Integrated MEMS-Tunable VCSELs Using a Self-Aligned Reflow Process

    Page(s): 144 - 152
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1560 KB) |  | HTML iconHTML  

    A simple microelectromechanical systems technology for wafer-scale integration of tunable vertical-cavity surface-emitting lasers (VCSELs) is presented. The key element is a self-aligned reflow process to form photoresist droplets, which serve as sacrificial layer and preform for a curved micromirror. Using a 3-D electromagnetic model, the half-symmetric cavity is optimized for singlemode emission. The technology is demonstrated for electrically pumped, short-wavelength (850 nm) tunable VCSELs, but is transferable to other wavelengths and material systems. Fabricated devices with 10 μm large current aperture are singlemode and tunable over 24 nm. An improved high-speed design with reduced parasitic capacitance enables direct modulation with 3 dB-bandwidths up to 6 GHz and data transmission at 5 Gbit/s. Small signal analysis shows that the intrinsic parameters (resonance frequency and damping) are wavelength dependent through the differential gain. View full abstract»

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  • Reconfigurable Digital Functionality of Composite Resonator Vertical Cavity Lasers

    Page(s): 153 - 159
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (810 KB) |  | HTML iconHTML  

    The composite resonator vertical cavity surface laser can perform multiple digital functionalities at greater than 10 GHz bandwidth, including: direct intensity modulation, wavelength division multiplexing, multilevel pulse amplitude modulation, and optical picosecond pulse generation. The unique attributes of these microcavity lasers arise from the two strongly coupled optical cavities which can be electrically injected independently. Reconfiguration among multiple functionalities is achieved by control of the three terminal signals input into the laser and can be achieved using a high-speed digital circuit whose logic can be adjusted to provide appropriate modulation voltages to the optically coupled laser cavities. The novel optical properties of composite resonators are reviewed with a focus on several different digital functionalities possible from this semiconductor laser. View full abstract»

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  • Hydrogen Detection Using a Functionalized Photonic Crystal Vertical Cavity Laser

    Page(s): 160 - 168
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (625 KB) |  | HTML iconHTML  

    A thin layer of palladium (Pd) was deposited on the surface of an etched air hole photonic crystal (PhC) vertical cavity surface emitting laser (VCSEL) to form a hydrogen gas (H2) sensor. H2 reacts with Pd, forming PdHx, which induces a shift in the complex refractive index. With Pd on its surface, the reflectivity of the top distributed Bragg reflector depends on the H2 concentration. We present device operation theory and experimental results showing a 60% output power increase and a 52 pm redshift of the lasing wavelength at 4% H2. Since the PhC VCSEL laser is single mode and the wavelength shift is comparable to the laser linewidth, the sensor can provide an accurate quantification of the H2 concentration over the range of 0-4% H2. View full abstract»

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  • Performance Enhancement of Blue Light-Emitting Diodes Without an Electron-Blocking Layer by Using p-Type Doped Barriers and a Hole-Blocking Layer of Low Al Mole Fraction

    Page(s): 169 - 174
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (531 KB) |  | HTML iconHTML  

    In this paper, the characteristics of the nitride-based blue light-emitting diode (LED) without an electron-blocking layer (EBL) are analyzed numerically. The emission spectra, carrier concentrations in the quantum wells (QWs), energy band diagrams, electrostatic fields, and internal quantum efficiency are investigated. The simulation results indicate that the LED without an EBL has a better hole-injection efficiency and smaller electrostatic fields in its active region over the conventional LED with an AlGaN EBL. The simulation results also show that the LED without an EBL has severe efficiency droop. However, when the p-type doped QW barriers and a hole-blocking layer are used, the efficiency droop is markedly improved and the electroluminescence emission intensity is greatly enhanced. View full abstract»

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  • Improved Output Power of InGaN-Based Ultraviolet LEDs Using a Heavily Si-Doped GaN Insertion Layer Technique

    Page(s): 175 - 181
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    In this paper, a high quality ultraviolet light-emitting diodes (UV-LEDs) at 375 nm was developed using a heavy Si-doping technique with metal organic chemical vapor deposition. By using high-resolution X-ray diffraction, the full width at half-maximum of the rocking curve shows that the GaN film inserting a heavily Si-doped GaN layer (Si-HDL) had high crystalline quality. From the transmission electron microscopy image, the threading dislocation density was decreased after inserting a Si-HDL between undoped and n-doped GaN layers by nanoscale epitaxial lateral overgrowth. As a result, a much smaller reverse current and a higher light output were achieved. The improvement of light output at an injection current of 20 mA was enhanced by 40%. Therefore, we can use an in-situ nano pattern without complex photolithography and etching process and improve the internal quantum efficiency of UV-LEDs. View full abstract»

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  • Low-Temperature Bonding of GaN on Si Using a Nonalloyed Metal Ohmic Contact Layer for GaN-Based Heterogeneous Devices

    Page(s): 182 - 186
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    A low-temperature integration process for GaN-based heterogeneous devices was demonstrated by low-temperature bonding with Cr/Au thin films. Nonalloyed Cr/Au ohmic contacts on n-type GaN were obtained by surface treatment with low-energy fast atom beams of Ar for 15 s prior to metal deposition on n-type GaN. The as-deposited Cr/Au (50/250 nm) contacts showed a smooth surface with a root-mean-square roughness of 1.8 nm. Au-Au surface-activated bonding was carried out at 150°C in ambient air after surface activation by an Ar radio-frequency plasma. The GaN/Si samples bonded at a low temperature were so strong that bulk fracture was observed after the tensile test. View full abstract»

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  • Simple Electroabsorption Calculator for Designing 1310 nm and 1550 nm Modulators Using Germanium Quantum Wells

    Page(s): 187 - 197
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (946 KB) |  | HTML iconHTML  

    With germanium showing significant promise in the design of electroabsorption modulators for full complementary metal oxide semiconductor integration, we present a simple electroabsorption calculator for Ge/SiGe quantum wells. To simulate the quantum-confined Stark effect electroabsorption profile, this simple quantum well electroabsorption calculator (SQWEAC) uses the tunneling resonance method, 2-D Sommerfeld enhancement, the variational method and an indirect absorption model. SQWEAC simulations are compared with experimental data to validate the model before presenting optoelectronic modulator designs for the important communication bands of 1310 nm and 1550 nm. These designs predict operation with very low energy per bit ( <; 30×fJ/bit). View full abstract»

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  • Investigation of Limits to the Optical Performance of Asymmetric Fabry-Perot Electroabsorption Modulators

    Page(s): 198 - 209
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (952 KB) |  | HTML iconHTML  

    We have investigated the suitability of surface-normal asymmetric Fabry-Perot electroabsorption modulators for short-distance optical interconnections between silicon chips. These modulators should be made as small as possible to minimize device capacitance; however, size-dependent optical properties impose constraints on the dimensions. We have thus performed simulations that demonstrate how the optical performance of the modulators depends on both the spot size of the incident beam and the dimensions of the device. We also discuss the tolerance to nonidealities such as surface roughness and beam misalignment. The particular modulators considered here are structures based upon the quantum-confined Stark effect in Ge/GeSi quantum wells. We present device designs that have predicted extinction ratios greater than 7 dB and switching energies as low as 10 fF/bit, which suggests that these silicon-compatible devices can enable high interconnect bandwidths without the need for wavelength division multiplexing. View full abstract»

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  • Photonic Crystal Silicon Optical Modulators: Carrier-Injection and Depletion at 10 Gb/s

    Page(s): 210 - 220
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1156 KB) |  | HTML iconHTML  

    We demonstrate 10 Gb/s modulation in a 200 μm photonic crystal silicon optical modulator, in both carrier-injection and depletion modes. In particular, this is the first demonstration of 10 Gb/s modulation in depletion mode and without pre-emphasis, in a Mach-Zehnder type modulator of this length, although moderate pre-emphasis can improve the signal quality. This is made possible by utilizing the slow-light of the photonic crystal waveguide, where the group index ng is ~ 30 and gives ~ 7 times enhancement in the modulation efficiency compared to rib-waveguide devices. We observe 10 Gb/s modulation at drive voltages as low as 1.6 V and 3.6 V peak-to-peak, in injection- and depletion-modes, respectively. View full abstract»

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  • High Operability 1024 ,\times, 1024 Long Wavelength Type-II Superlattice Focal Plane Array

    Page(s): 221 - 228
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    Electrical and radiometric characterization results of a high-operability1024 × 1024 long wavelength infrared type-II superlattice focal plane array are described. It demonstrates excellent quantum efficiency operability of 95.8% and 97.4% at operating temperatures of 81 K and 68 K, respectively. The external quantum efficiency is 81% without any antireflective coating. The dynamic range is 37 dB at 81 K and increases to 39 dB at 68 K operating temperature. The focal plane array has noise equivalent temperature difference as low as 27 mK and 19 mK at operating temperatures of 81 K and 68 K, respectively, using f/2 optics and an integration time of 0.13 ms. View full abstract»

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  • 10-Gb/s 850-nm CMOS OEIC Receiver With a Silicon Avalanche Photodetector

    Page(s): 229 - 236
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1006 KB) |  | HTML iconHTML  

    We present a 10-Gb/s optoelectronic integrated circuit (OEIC) receiver fabricated with standard 0.13-μm complementary metal-oxide-semiconductor (CMOS) technology for 850-nm optical interconnect applications. The OEIC receiver consists of a CMOS-compatible avalanche photodetector (CMOS-APD), a transimpedance amplifier (TIA), an offset cancellation network, a variable equalizer (EQ), a limiting amplifier (LA), and an output buffer. The CMOS-APD provides high responsivity as well as large photodetection bandwidth. The TIA is composed of two-stage differential amplifiers with high feedback resistance of 4 kΩ. The EQ compensates high-frequency loss by controlling the boosting gain with a capacitor array. The LA consists of five-stage gain cells with active feedback and negative capacitance to achieve broadband performance. With the OEIC receiver, we successfully demonstrate transmission of 10-Gb/s optical data at 850 nm with a bit error rate of 10-12 at the incident optical power of -4 dBm. The OEIC receiver has the core chip area of about 0.26 mm2 and consumes about 66.8 mW. View full abstract»

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  • Hybrid {\rm As}_{2}{\rm S}_{3} Mach-Zehnder Interferometer Prepared by Magnetron Sputtering and its Photodarkening Effect

    Page(s): 237 - 243
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    Several hybrid integrated As2S3 Mach-Zehnder interferometers with linear tapers and grating couplers have been successfully fabricated using magnetron sputtering on LiNbO3 substrate. It demonstrated how As2S3 waveguide can be integrated with the LiNbO3 waveguide to create a hybrid interferometer for use in chalcogenide photonics. The photo-induced changes in the group and effective index of the As2S3 waveguide were measured and compared to values reported for films prepared by thermal evaporation. These photo-induced phenomena are found to be different from those reported for As2S3 bulk glass and thermally evaporated As2S3 film. View full abstract»

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  • Fully Integrated Mach-Zhender MEMS Interferometer With Two Complementary Outputs

    Page(s): 244 - 251
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (711 KB) |  | HTML iconHTML  

    In this paper, a novel Mach-Zhender interferometer for spectroscopy applications is presented. The interferometer is fully integrated on an silicon on insulator wafer using deep reactive ion etching technology, the moving mirror is coupled to a comb drive microelectromechanical systems (MEMS) actuator. Optical propagation inside the MEMS structure is modeled and the diffraction effect is studied. Practical results show the complementary nature of the two outputs and a resolution of 25 nm at 1.55 μm is reported when using the interferometer as an Fourier transform infrared spectrometer. The complementary nature of the interferometer can be further used for source noise reduction. View full abstract»

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  • Waveguide Optical Isolators for Integrated Optics

    Page(s): 252 - 260
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (679 KB) |  | HTML iconHTML  

    Waveguide optical isolators are investigated for an application to integrated optics. A nonreciprocal loss shift isolator has the advantage of high compatibility with optical active devices. The interferometric waveguide optical isolator that uses nonreciprocal phase shift brought about by the first-order magneto-optic effect is applicable to a variety of waveguide platforms. In a silicon-on-insulator (SOI) waveguide, the low refractive index of buried oxide layer enhances the magneto-optic phase shift, which contributes to reduce the device size of isolator. We developed the surface activated direct bonding technique to integrate a magneto-optic garnet crystal onto dissimilar crystals. The performance of SOI waveguide optical isolator was demonstrated with an optical isolation of 21 dB at a wavelength of 1559 nm. View full abstract»

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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