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Selected Topics in Quantum Electronics, IEEE Journal of

Issue 2 • Date June 1996

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Displaying Results 1 - 25 of 34
  • Introduction To The Issue On Integrated Optics

    Publication Year: 1996 , Page(s): 149 - 150
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    Freely Available from IEEE
  • Structural phase diagram of Hx/Li1-xNbO3 waveguides: The correlation between optical and structural properties

    Publication Year: 1996 , Page(s): 187 - 196
    Cited by:  Papers (48)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (295 KB)  

    We show that proton exchanged Hx/Li1-xNbO3 single-crystalline solid solutions exhibit very complex structural chemistry, which is different from those known for powders. Seven crystallographic phases have been identified in Hx/Li1-xNbO3 layers. Correlation between the crystal structure and the ordinary and extraordinary refractive indices has been experimentally determined which allows us to explain some of the observed optical phenomena and to predict the characteristics of the great variety of proton exchanged waveguides. View full abstract»

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  • All-optical waveguide-type gain switch utilizing intersubband transition

    Publication Year: 1996 , Page(s): 410 - 417
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    All-optical switching performance of waveguide-type device utilizing intersubband transition is investigated by analyzing the position-dependent change of optical power densities and carrier densities in the waveguide. In the device, the three lowest energy-level subbands in the conduction band structure of asymmetric coupled quantum wells are used. The optical excitation pulse excites the electrons in the first subband to the third subband and the stimulated emission between the third subband and second subband amplifies the optical signal pulse. We find that the signal pulse is notably amplified when the excitation pulsewidth is less than the relaxation time of the third subband. The calculated results show that wavelength conversion from 1.35 to 1.6 μm with a gain of more than 10 dB is achieved by the excitation using an optical pulse with 1.5-ps width. This demonstrates the effectiveness of using a waveguide-type device structure with pulsed operation to make devices with a high-optical gain. We also derive a simple approximation for the optical gain. We show that the approximation gives results in good agreement with the results of the rigorous simulation using a finite difference method and the approximation is useful for designing devices View full abstract»

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  • Ultrafast monolithically integrated InP-based photoreceiver: OEIC-design, fabrication, and system application

    Publication Year: 1996 , Page(s): 418 - 424
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (180 KB)  

    An InP-based photoreceiver OEIC for λ=1.55 μm with a bandwidth of 27 GHz is reported. The receiver design, fabrication and characterization is presented. The device consists of an optical waveguide-fed pin-photodiode and a coplanar traveling-wave amplifier being composed of four GaInAs-AlInAs-InP-HEMT's. The photodiode exhibits an external quantum efficiency of 30% and a 3-dB power bandwidth of 35 GHz. HEMT's with 0.7-μm gate length, integrated on semi-insulating optical waveguide layers show cutoff frequencies fT/fmax of 37/100 GHz at zero gate bias. Traveling-wave amplifiers with 0.5-μm gate HEMT's have 28-GHz bandwidth. The receiver OEIC is packaged into a module with fiber pigtail and operates successfully within an SDH based 20-Gb/s transmission system. An overall system sensitivity of -30.5 dBm was achieved at a BER=10-9 after signal transmission over 198-km dispersion shifted fiber View full abstract»

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  • Integrated optic-devices characterization with the Wigner transform

    Publication Year: 1996 , Page(s): 181 - 186
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    The characterization of integrated optic devices with the Wigner transform is presented. The Wigner transform of planar waveguides, waveguide couplers and optical modulators is computed. It allows the determination of various parameters of the integrated optic devices such as the parity and shape of waveguide modes, the effective numerical aperture, the distance between coupled waveguides, the coupling efficiency, etc. Also presented are the set-ups for the Wigner transform measurement in different phase space coordinates as space-angle and time-frequency View full abstract»

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  • Comparison between difference-frequency generation and parametric fluorescence in quasi-phase-matched lithium niobate stripe waveguides

    Publication Year: 1996 , Page(s): 385 - 395
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB)  

    Tuning curves and gain are two relevant parameters for integrated optical parametric oscillators. We show in this paper that they can be determined with a good precision without building a high-finesse cavity by measurement of the optical parametric fluorescence and difference-frequency generation. In the first part of this paper, we compare theoretically the guided optical parametric fluorescence and the guided difference-frequency generation in the quasi-phase matching configuration. In the second part, we compare experimental results on optical parametric fluorescence in the 1.2-2.2-μm region and optical difference-frequency generation from a 1.55-μm laser diode using a pump wavelength between 775-795 nm in quasi-phase-matched lithium niobate stripe waveguides. This comparison shows that the gain measured by both methods is identical, but, while parametric fluorescence allows us to obtain the quasi-phase-matching curve, the difference-frequency generation gives a simpler and more accurate measurement of the gain. The combination of these two techniques provides therefore a powerful tool for evaluating the different fabrication processes of the nonlinear waveguides, without actually fabricating a parametric oscillator View full abstract»

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  • S-matrix oriented CAD-tool for simulating complex integrated optical circuits

    Publication Year: 1996 , Page(s): 257 - 262
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (144 KB)  

    A design tool for simulation of complex integrated optical circuits, based on a professional microwave design system has been developed. Implementation of a number of components is described and a simulation example of an add-drop node using a 4×4 phased array is presented View full abstract»

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  • Coherent control of quantum-well excitons in a resonant semiconductor microcavity for high-speed all-optical switching

    Publication Year: 1996 , Page(s): 401 - 409
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (272 KB)  

    Coherent control of excitons in quantum wells embedded in a resonant planar semiconductor microcavity versus in quantum wells without the cavity at high repetition rates is investigated theoretically to determine the practical constraints for application in high bit-rate optical switching. It is shown that π-shifted pulse pairs are optimal to coherently populate and depopulate the QW on the 100-fs timescale. For the cavity-free case, the small optical nonlinearity will require devices incorporating ~100 quantum wells; the resonant enhancement of the confined mode for the case of the cavity leads to an effective increase in the optical nonlinearity and thus a reduction of the required number of quantum wells to ~10. In addition, switch architectures that avoid interferometers, and thus will have superior temperature and mechanical stability, based on the microcavity are proposed. We believe that although room-temperature operation of a 100-Gb/s switch based on this principle may be difficult, operation at liquid-nitrogen temperature should be feasible View full abstract»

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  • Monolithic integration of multiple-quantum-well lasers and modulators for high-speed transmission

    Publication Year: 1996 , Page(s): 326 - 335
    Cited by:  Papers (27)  |  Patents (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    Monolithically integrated single frequency lasers and electroabsorption modulators are attracting considerable interest as optical sources for long-haul and high-bit-rate fiber-optic links. Their frequency chirpless nature has indeed allowed nonreturn-to-zero (NRZ) transmission beyond the chromatic dispersion limit. They also offer a great potential as soliton pulse generators. This paper discusses the many integration schemes devised for their realization with particular emphasis on the identical active layer (IAL) approach. Recent progress in their high-speed applications is reported View full abstract»

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  • Integrated optical, wavelength selective, acoustically tunable 2×2 switches (add-drop multiplexers) in LiNbO3

    Publication Year: 1996 , Page(s): 263 - 269
    Cited by:  Papers (11)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (180 KB)  

    Fully packaged, polarization independent, integrated acoustooptic 2×2 switches have been developed which can be also used as add/drop multiplexers. The devices have been fabricated in X-cut Y-propagating LiNbO3 and can be operated at wavelengths around 1550 nm. They consist of passive polarization splitters and acoustooptic TE-TM converters with weighted coupling. A filter bandwidth of 2.0 nm and a tuning range of 130 nm have been obtained. The fiber-to-fiber insertion loss is <4.6 dB and a residual polarization dependence of 1.3 dB for bar-state and 0.1 dB for cross-state routing has been achieved View full abstract»

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  • PHASAR-based WDM-devices: Principles, design and applications

    Publication Year: 1996 , Page(s): 236 - 250
    Cited by:  Papers (308)  |  Patents (49)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (360 KB)  

    Wavelength multiplexers, demultiplexers and routers based on optical phased arrays play a key role in multiwavelength telecommunication links and networks. In this paper, a detailed description of phased-array operation and design is presented and an overview is given of the most important applications View full abstract»

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  • Asymmetric discretization of wave equation as boundary condition in modal analysis [integrated optics]

    Publication Year: 1996 , Page(s): 174 - 180
    Cited by:  Papers (3)
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    A general method of deriving finite-difference schemes suitable for the discretization of the wave equation along the boundary of a simulation region has been developed, thereby eliminating the need of artificially imposed boundary conditions for modal calculations. Its effectiveness is demonstrated through examples View full abstract»

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  • Linear phase tracking in a coherence modulation electrical sensor system using integrated LiNbO3 modulator/demodulator

    Publication Year: 1996 , Page(s): 319 - 325
    Cited by:  Papers (4)
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    We report an interferometric sensor system, based on coherence modulation of light and LiNbO3 integrated optics technology. We describe a phase detection scheme designed to retrieve the absolute phase variations produced by a sensor system where the sensor signal is electronically applied to an electro-optic modulator. The system consists of an imbalanced LiNbO3 Mach-Zehnder transducer fed by a self-powered charge generating sensor, and an optoelectronic central processing unit including a second electrooptic Mach-Zehnder working as an optical demodulator and featuring a matched path-imbalance. Electrical feedback is applied to this second interferometer in an active demodulation scheme, allowing a linear tracking of the signal phase up to 7-π radians View full abstract»

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  • Pulse generation for soliton systems using lithium niobate modulators

    Publication Year: 1996 , Page(s): 300 - 310
    Cited by:  Papers (31)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (252 KB)  

    We describe the principle of operation and performance of several soliton pulse sources and also a complete soliton transmitter based on lithium niobate modulators. Subsystems based on lithium niobate modulators are attractive because the modulators are now commercially available, qualified for system use, can operate up to very high speeds, and can operate over a wide wavelength range. The pulse sources we describe are based on two techniques. The first is the chirped pulse compression technique in which one or two sinusoidally driven modulators generate frequency chirped pulses that are subsequently compressed to the desired width using dispersion in a fiber. In the second technique, sinusoidally driven modulators are cascaded serially to form pulses. Using these techniques we produced nearly transform-limited pulses at repetition rates up to 15 GHz with a FWHM pulsewidths from 10-33% of the pulse period. A complete soliton transmitter using a single modulator to simultaneously generate optical pulses and encode data is also discussed. The performance of this compact transmitter in a 2.5-Gb/s soliton system experiment is comparable to other more common soliton transmitters View full abstract»

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  • Narrow-beam aluminum-mirrored fiber optical-taps with controllable tapped power

    Publication Year: 1996 , Page(s): 221 - 225
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (84 KB)  

    A fiber optical-tap has been fabricated and tested. Two separate fiber tips were polished with an angle of 45°, and one of the tips was coated with aluminum inside a vacuum deposition unit. Then, the coated and uncoated polished tips were spliced together using a fusion splicer to form a fiber optical-tap. The power of the tapped light is controllable by controlling the thickness of the aluminum coating during vacuum deposition. As the aluminum coating thickness increases, the amount of tapped light increases and consequently the power transmitted after the fiber optical-tap decreases. For the same aluminum coating thickness, the tapped beam power from a single-mode fiber tap is higher than that from a multimode fiber tap. In addition to the feasibility of tapping a narrow light beam and controlling its power, the fabricated optical tap has a short length, which means that it can be integrated easily in optical signal-processing circuits. The mechanical strength of the tap has been tested in the laboratory and found to be capable of supporting between 75 and 180 g before breaking View full abstract»

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  • Dynamic beam propagation method for flared semiconductor power amplifiers

    Publication Year: 1996 , Page(s): 378 - 384
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB)  

    In this paper, we present the results of a dynamic two-dimensional time-domain beam propagation method (two spatial dimensions plus time) for simulating travelling wave semiconductor optical amplifiers with nonuniform transverse section in pulsed regime. Using the effective refractive index method, the paraxial approximation and a moving timeframe, we reduce the scalar wave equation to a nonlinear parabolic partial differential equation for the slow complex envelope of the electric field. Diffraction, refractive index dispersion up to the second order, gain saturation and gain dispersion are included in the model. We numerically solve the equation through a locally one-dimensional (LOD) method employing both finite-difference techniques and FFT-based pseudospectral methods View full abstract»

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  • Variable group-delay dispersion equalizer using lattice-form programmable optical filter on planar lightwave circuit

    Publication Year: 1996 , Page(s): 270 - 276
    Cited by:  Papers (34)  |  Patents (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB)  

    The authors report, in detail, an integrated-optic variable group-delay dispersion equalizer based on a lattice-form programmable optical filter. The variable dispersion equalizer consists of an alternating cascade of symmetrical and asymmetrical Mach-Zehnder interferometers. An equalizer with nine symmetrical and eight asymmetrical interferometers is fabricated on a planar lightwave circuit and its dispersion varied step by step from -681 to +786 ps/nm in the operational frequency range of 16.3 GHz. The effectiveness of the equalizer is shown by compensating the dispersion of three different fibers with a single equalizer. The performance of the equalizer is also evaluated and examined by numerical investigations View full abstract»

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  • Analytical expressions for the FM and AM responses of an integrated laser-modulator

    Publication Year: 1996 , Page(s): 336 - 340
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB)  

    The need for low-chirp and compact transmitters for high-bit-rate optical links has led to the development of integrated laser electroabsorption modulators (ILM). We have investigated feedback effects inducing frequency chirp by developing a model treating the ILM as a whole and obtained analytical expressions of the FM and AM responses. The variation of the frequency chirp with the residual facet reflectivity of the modulator section is calculated. The model predicts the unusual peak in the measured frequency responses and has been used to define design rules View full abstract»

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  • Mode coupling analysis for the design of refractive ion exchange integrated optical components

    Publication Year: 1996 , Page(s): 165 - 173
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (292 KB)  

    Refractive integrated optical planar components such as prisms and lenses, consist of alternating regions of high- and low-index planar waveguides. Boundary transmission losses depend on the coupling efficiency between the fundamental modes in the two regions. Hence, a choice of appropriate parameters to achieve maximum coupling efficiency is an important design criterion of these components. We propose the use of the Ritz-Galerkin (RG) procedure to characterize the modal fields in planar graded index waveguides for obtaining coupling efficiency and, hence, the optimal design features. The procedure is “exact” and simple analytical expressions have been obtained for coupling efficiency. Further, coupling to higher order modes can also be obtained to estimate the background noise in component design when parameters deviate from the optimum. To confirm the convergence, results have been compared with the exact numerical procedure based on the multilayer staircase approximation. Various variational procedures limited to the fundamental mode coupling efficiency calculations are also summarized in this paper along with a discussion on their accuracies View full abstract»

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  • Design and fabrication of 1.31-1.55-μm phased-array duplexer on InP

    Publication Year: 1996 , Page(s): 251 - 256
    Cited by:  Papers (4)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (172 KB)  

    1.31-1.55-μm InP duplexers based on low-order waveguide arrays have been modeled, fabricated and characterized. By introducing lateral offsets between straight and curved waveguides, polarization insensitive devices with 5-dB on-chip loss, and less than -30-dB crosstalk over 100-nm wavelength range have been obtained, showing good agreement between theory and experiment View full abstract»

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  • High-speed polarization scrambler with adjustable phase chirp

    Publication Year: 1996 , Page(s): 311 - 318
    Cited by:  Papers (13)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (356 KB)  

    We report on the operation and performance of a novel electrooptic polarization scrambler that is capable of generating any desired combination of optical phase and polarization modulation. The scrambler comprises a dual-drive Mach-Zehnder-type intensity modulator on lithium niobate and an external microoptic polarization splitter which combines the two complementary outputs of the integrated-optic intensity modulator in orthogonal polarization states. The modulation indexes of the sinusoidal phase and polarization modulation in the output light can be varied independently of each other via the amplitudes and phases of the two drive voltages to the Mach-Zehnder modulator. The scrambler has a 3-dB modulation bandwidth of 14 GHz and operates in the 1.5-1.6-μm wavelength range with an overall fiber-to-fiber insertion loss of less than 5 dB. At 5 GHz modulation frequency and electric drive powers between 390-2030 mW, we demonstrate phase-chirped and chirp-free depolarization with a residual degree of polarization of less than 0.02 and continuously variable phase modulation to 2.3-rad peak phase deviation View full abstract»

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  • Design of a spotsize-converter-integrated laser diode (SS-LD) with a lateral taper, thin-film core and ridge in the 1.3-μm-wavelength region based on the 3-D BPM

    Publication Year: 1996 , Page(s): 348 - 354
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (164 KB)  

    In order to develop spotsize-converter-integrated laser diodes (SS-LDs) with high efficiency and large-misalignment tolerances in the 13-μm-wavelength region, spotsize converters (SSCs), which consist of lateral taper, thin-film core and ridge, are investigated employing the three-dimensional (3-D) semivectorial finite-difference beam propagation method (FD-BPM) with nonequidistant discretization. The sum of the spot-conversion loss and coupling loss between the laser diode (LD) eigenmode and the single-mode fiber (SMF) eigenmode are calculated for various structural parameters. Small loss of around 1.5 dB can be achieved by introducing a nonlinear taper. The fabrication tolerances for the SSCs are also clarified. The calculated results agree well with the results for actually fabricated SS-LD's. It is also shown that the radiation loss and coupling characteristics of the SS-LDs with a buried thin-film core structure can be improved using a nonlinear taper View full abstract»

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  • Fabrication and characterization of high-speed polyurethane-disperse red 19 integrated electrooptic modulators for analog system applications

    Publication Year: 1996 , Page(s): 289 - 299
    Cited by:  Papers (24)  |  Patents (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (220 KB)  

    The fabrication and characterization of polymeric electrooptic modulators, made of a thermally crosslinkable polyurethane with Disperse Red 19 side chains, are summarized in this paper. Straight channel and Mach-Zehnder modulators have been fabricated, packaged and tested for the fiber-optic analog transmission system applications. Device performances including halfwave voltage, insertion loss, on-off ratio, and modulation frequency responses were measured. Long-term halfwave voltage stability, dc-bias voltage stability, and optical power handling capability at 1.3-μm wavelength were investigated. A carrier-to-noise ratio of 53 dB and 80-channel television transmission have been demonstrated using the packaged polymer modulators View full abstract»

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  • A universal optical heterostructure for photonic integrated circuits: a case study in the AlGaAs material system

    Publication Year: 1996 , Page(s): 341 - 347
    Cited by:  Papers (1)
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    An approach for the realization of a single heterostructure for multiple optical device applications in a photonic integrated circuit environment is addressed from the standpoint of building into the heterostructure separate device features. In particular, a low compositionally graded depressed cladding laser structure is shown to have a large mode, compared to a structure optimized for maximum confinement factor, and a radiation loss an order of magnitude lower than for a structure without the inner cladding, features which are important for fiber coupling and for compact bends. By incorporating a narrow gap section into the barrier layer, a bulk electroabsorption modulator can be integrated into the same structure that contains quantum wells for optical amplifiers. Data are presented on the device properties of a single heterostructure when used as large optical cavity lasers, s-bends, and bulk electroabsorption modulators. The only laser parameter affected by the incorporation of the modulator is the transparency current density which is increased 25% over standard structures. The performance of rib delineated s-bends is exceeded only by native oxide defined small optical cavity laser structures. The electroabsorption modulator, which was activated in a disordered section under reverse bias, had a modulation depth approximately 1/3 that predicted by model studies which was attributed to the depletion electric field profile. Methods for improving the modulation depth while lowering the transparency current density are outlined View full abstract»

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  • Optical properties of polymer waveguides dispensed on an erbium/ytterbium codoped glass

    Publication Year: 1996 , Page(s): 373 - 377
    Cited by:  Papers (3)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (100 KB)  

    A composite waveguide was fabricated by dispensing polymer on top of an erbium/ytterbium codoped bulk glass. The parabolic surface of the polymer layer induces a transverse graded index waveguide behavior enabling tighter lateral confinement of light than in a typical step-index multimode waveguide. Spontaneous emission of light in the 1520-1570-nm band has been observed, We have also observed up to 1.7-dB enhancement of transmitted signal with 210 mW of launched 975-nm pump light in a waveguide 1.0-cm long View full abstract»

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Aims & Scope

Papers published in the IEEE Journal of Selected Topics in Quantum Electronics fall within the broad field of science and technology of quantum electronics of a device, subsystem, or system-oriented nature.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
John Cartledge
Queen's University