| 1. |
- Yoo, S. J. B., et al.
(författare)
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Spectral phase encoded time spread optical code division multiple access technology for next generation communication networks Invited
- 2007
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Ingår i: Journal of Optical Networking. - 1536-5379. ; 6:10, s. 1210-1227
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Tidskriftsartikel (refereegranskat)abstract
- We overview and summarize the progress of the spectral phase encoded time spreading (SPECTS) optical code division multiple access (O-CDMA) technology. Recent progress included a demonstration of a 320 Gbit/s (32-user x 10 Gbit/s) all-optical passive optical network testbed based on the SPECTS O-CDMA technology and a theoretical prediction of the spectral efficiency at 100% and above. In particular, InP-based integrated photonics allows implementation of SPECTS O-CDMA transmitters and receivers monolithically integrated on a chip. The integrated InP chip technology not only allows robust and compact configurations for practical and low-cost O-CDMA network deployments but also offers code reconfigurations at rapid rates for secure communication applications.
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| 2. |
- Dhanabalan, D., et al.
(författare)
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Studies on Schottky Barrier Diodes Fabricated using Single-Crystal Wafers of β-Ga2O3 Grown by the Optical Floating Zone Technique
- 2022
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Ingår i: Physica status solidi. B, Basic research. - : Wiley. - 0370-1972 .- 1521-3951. ; 259:2
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Tidskriftsartikel (refereegranskat)abstract
- β-Ga2O3 is one of the most promising wide-bandgap materials for optoelectronic applications as well as a conducting substrate for GaN-based device technologies. Single crystals of undoped β-Ga2O3 are grown by the optical floating zone technique utilizing compressed dry air as growth atmosphere. The properties of β-Ga2O3 are highly anisotropic. Optimization of the processing recipe for wafers along different orientations suitable for device development is conducted. Structural, optical, and electrical properties of the wafers are determined. Efforts are made to fabricate Schottky diodes based on Pt/Ti/Au–β-Ga2O3–Ti/Au device structures. Devices are fabricated on (−201) cut wafers. The device characteristics are discussed in detail.
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| 3. |
- Cheung, S. T. S., et al.
(författare)
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Monolithically integrated 10-GHz ring colliding pulse mode-locked laser for on-chip coherent communications
- 2012
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Ingår i: 2012 Conference on Lasers and Electro-Optics, CLEO 2012. ; , s. 6326206-
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Konferensbidrag (refereegranskat)abstract
- We report a 10-GHz ring resonator colliding pulse mode-locked (CPM) laser with tunable couplers for InP-based monolithically integrated optical coherent communication system applications. Optimization included adjusting the saturable absorber reverse bias, driving RF-frequency, and amplifier gain current. Hybrid mode-locking (HML) resulted in a minimal pulse width of 10.1ps for 6 nm spectral width.
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| 4. |
- Baek, J. H., et al.
(författare)
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10-GHz and 20-GHz channel spacing high-resolution AWGs on InP
- 2009
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 21:5, s. 298-300
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Tidskriftsartikel (refereegranskat)abstract
- This letter reports on 10-GHz and 20-GHz channel-spacing arrayed waveguide gratings (AWGs) based on InP technology. The dimensions of the AWGs are 6.8 × 8.2 mm2 and 5.0 × 6.0 mm2, respectively, and the devices show crosstalk levels of 12 dB for the 10-GHz and 17 dB for the 20-GHz AWG without any compensation for the phase errors in the arrayed waveguides. The root-mean-square phase errors for the center arrayed waveguides were characterized by using an optical vector network analyzer, and are 18° for the 10-GHz AWG and 28° for the 10-GHz AWG.
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| 5. |
- Darakchieva, Vanya, 1971-, et al.
(författare)
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Phonons in strained AlGaN/GaN superlattices
- 2007
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Ingår i: 6th International Symposium on Blue Laser and Light Emitting Diodes,2006. - Physica Status Solidi, vol C4 : WILEYVCH Verlag GmbH & Co. KGaA. ; , s. 170-
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Konferensbidrag (refereegranskat)
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| 6. |
- Fontaine, N. K., et al.
(författare)
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Determination of 20 GHz InP AWG phase errors by measurement of AWG pulse train
- 2007
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Ingår i: 2007 IEEE LEOS Annual Meeting Conference Proceedings. - : IEEE. - 142440925X - 9781424409259 ; , s. 725-726
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Konferensbidrag (refereegranskat)abstract
- The phase errors of a 20 GHz AWG fabricated on InP are determined by measuring the intensity and phase of the pulse train produced by the transmission of a short pulse through an AWG.
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| 7. |
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| 8. |
- Hammar, M., et al.
(författare)
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Topography dependent doping distribution in selectively regrown InP studied by scanning capacitance microscopy
- 1998
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 72:7, s. 815-817
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Tidskriftsartikel (refereegranskat)abstract
- We have used scanning capacitance microscopy (SCM) to study the dopant distribution in regrown InP with high sensitivity and spatial resolution. Sulfur or iron doped InP was selectively regrown around n-doped InP mesas using hydride vapor phase epitaxy, and the resulting structure was imaged in cross section by SCM. For calibration purposes, reference layers with known doping levels were grown directly on top of the region of interest. Dramatic variations in the carrier concentration around the mesa, as well as pronounced differences in the behavior of S and Fe are observed. We correlate these findings to the growth and doping incorporation mechanisms. © 1998 American Institute of Physics.
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| 9. |
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| 10. |
- Kjebon, Olle, 1960-, et al.
(författare)
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Two-section InGaAsP DBR-lasers at 1.55 mu;m wavelength with 31 GHz direct modulation bandwidth
- 1997
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Ingår i: Indium Phosphide and Related Materials, 1997., International Conference on. ; , s. 665-668
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Konferensbidrag (refereegranskat)abstract
- The small signal modulation response of two-section InGaAsP DBR-lasers at 1.55 mu;m wavelength was investigated. The response was fitted to a general transfer function and it was found that for almost all lasers the response could be described by a three pole model consisting of the laser response from the standard rate equations and an additional first order low pass roll-off. The lasers exhibited reduced damping and increased resonance frequency due to what we believe is detuned loading. This led to a maximum bandwidth of 30 GHz for lasers described by the three pole model. Some lasers exhibited an additional effect which we believe is cavity resonant enhancement of one of the modulation side-bands. This effect increased the maximum -3dB bandwidth to 31 GHz but could not be described by a three pole model
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| 11. |
- Lourdudoss, Sebastian, et al.
(författare)
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Heteroepitaxy and selective epitaxy for discrete and integrated devices
- 2006
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Ingår i: 2006 CONFERENCE ON OPTOELECTRONIC AND MICROELECTRONIC MATERIALS & DEVICES. - NEW YORK : IEEE. - 9781424405770 ; , s. 309-311
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Konferensbidrag (refereegranskat)abstract
- We present first results on heteroepitaxy of InP on silicon on insulator (SOI). We also demonstrate InP nanopillar fabrication by means of selective epitaxy. Selective epitaxy is also exploited to fabricate advanced photonic integrated devices for Optical Code Division Multiplex Access (OCDMA) networking applications.
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| 12. |
- Ougazzaden, A., et al.
(författare)
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Progress on new wide bandgap materials BGaN, BGaAlN and their potential applications
- 2007
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Ingår i: Quantum Sensing and Nanophotonic Devices IV. - : SPIE. - 9780819465924 ; , s. G4791-G4791
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Konferensbidrag (refereegranskat)abstract
- The development of wide band gap semiconductors extends their applications in optoelectronics devices to the UV domain. Compact lasers and high sensitivity APD detectors in UV range are currently needed for different applications such as, purification, covert communication and real time detection of airborne pathogens. Until now, the full exploitation of these potential materials has been limited by the lack of suitable GaN substrates. Recently, a novel class of materials has been reported based on BGaN and BAlN, potentially reducing the crystal defect densities by orders of magnitude compared to existing wide band gap heterostructures. Characteristics of these new alloys are similar to those of AlGaN materials with the advantage that these can be lattice matched to AlN and SiC substrates. In addition, these materials offer the possibility of using quaternary BAlGaN alloys at Ultra Violet (UV) wavelengths and hence lead to more degrees of freedom in designing sophisticated device structures. In this paper we describe the MOVPE growth conditions used to incorporate boron in GaN and AlGaN. Detailed characterization and analysis in terms of structural and electrical properties are discussed.
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| 13. |
- Scares, F. M., et al.
(författare)
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20GHz channel spacing InP-based arrayed waveguide grating
- 2007
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Ingår i: 2007 33rd European Conference and Exhibition of Optical Communication, ECOC 2007. - : IEEE conference proceedings. - 9783800730421
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Konferensbidrag (refereegranskat)abstract
- We demonstrate a 10-channel InP-based Arrayed-Waveguide Grating (dimensions = 5.0×6.0 mm2) with a 20-GHz channel spacing. The excess loss of the AWG is 5.5-6.3 dB, and the crosstalk level is below -15 dB.
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| 14. |
- Seo, S. W., et al.
(författare)
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Monolithically integrated InP photonic micro systems on a chip for O-CDMA and OAWG applications
- 2007
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Ingår i: 2007 Photonics in Switching, PS. - 142441122X - 9781424411221 ; , s. 97-98
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Konferensbidrag (refereegranskat)abstract
- A monolithically integrated InP chip for optical arbitrary waveform generation (OAWG) and/or pulse-coding/decoding is demonstrated using a 20-GHz AWG pair and 10 high-speed phase modulators. The fabrication and performance of the InP chip will be presented.
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| 15. |
- Soares, F. M., et al.
(författare)
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Compact InP-Based 16-channel O-CDMA encoder/decoder
- 2007
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Ingår i: 2007 IEEE LEOS annual meeting conference proceedings. - : IEEE. - 142440925X - 9781424409259 ; , s. 723-724
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Konferensbidrag (refereegranskat)abstract
- A very compact InP-Based 16-channel O-CDMA encoder-/decoder chip (3.8mm × 6.8mm) has been designed, fabricated and characterized. The device successfully performs O-CDMA spectral encoding.
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| 16. |
- Soares, F. M., et al.
(författare)
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InP-based arrayed-waveguide grating with a channel spacing of 10 GHz
- 2008
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Ingår i: OFC/NFOEC - Conf. Opt. Fiber Commun./Natl. Fiber Opt. Eng. Conf.. - 9781557528551 ; , s. -69
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Konferensbidrag (refereegranskat)abstract
- We realize a high-precision 10-channel InP-based Arrayed-Waveguide Grating (AWG) with a 10-GHz channel spacing. The AWG showed approximately 10dB excess-loss, 10 dB crosstalk, and 8.2 × 6.8 mm2 dimensions.
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| 17. |
- Soares, Francisco M., et al.
(författare)
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Monolithic InP 100-Channel X 10-GHz Device for Optical Arbitrary Waveform Generation
- 2011
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Ingår i: IEEE Photonics Journal. - 1943-0655. ; 3:6, s. 975-985
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate monolithic integration of a 100-channel arrayed-waveguide grating (AWG) with 10-GHz channel spacing and 100 optically controlled Michelson-interferometer-based phase and amplitude modulators. The high-resolution AWG showed better than -15-dB crosstalk, and the modulator extinction ratio was better than 20 dB with either electrical or optical modulation control. The twin-integrated devices comprise a 50-mm diameter InP wafer with 1200 independent optoelectronic components.
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| 18. |
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| 19. |
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| 20. |
- Arulkumaran, S., et al.
(författare)
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Enhancement of both direct-current and microwave characteristics of AlGaN/GaN high-electron-mobility transistors by furnace annealing
- 2006
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 88:2
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Tidskriftsartikel (refereegranskat)abstract
- The enhancement of both direct-current (dc) and microwave characteristics of AlGaN/GaN high-electron-mobility transistors (HEMTs) were demonstrated by conventional furnace annealing at 400 degrees C for 5 min. Due to the improvement in Ni/Au Schottky contact properties by furnace annealing, about 17%, 34%, 23%, and 25% of enhancements in maximum drain current density, maximum extrinsic transconductance (g(m max)), cutoff frequency and maximum oscillation frequency were observed, respectively. A positive threshold voltage shift and the increase in g(m max) can also be correlated to the improved Schottky parameters such as ideality factor and barrier height. The annealed devices exhibited low reverse gate-leakage-current by more than three orders of magnitude and low drain-leakage-current by two orders of magnitude. Correspondingly, the devices exhibited 55% of higher breakdown voltage after annealing. The furnace annealing is an effective and viable means to enhance both dc and microwave characteristics of AlGaN/GaN HEMTs.
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| 21. |
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| 22. |
- Broeke, Ronald G., et al.
(författare)
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Optical-CDMA in InP
- 2007
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Ingår i: IEEE Journal of Selected Topics in Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-260X .- 1558-4542. ; 13:5, s. 1497-1507
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes the InP platforms for photonic integration and the development on these platforms of an optical code division multiple access (O-CDMA) system for local area networks. We demonstrate three building blocks of this system: an optical pulse source, an encoder/decoder pair, and a threshold detector. The optical pulse source consists of an integrated colliding pulse-mode laser with nearly transform-limited 10 Gb/s pulses and optical injection locking to an external clock for synchronization. The encoder/decoder pair is based on arrayed waveguide gratings. Bit-error-rate measurements involving six users at 10 Gb/s showed error-free transmission, while O-CDMA codes were calibrated using frequency resolved optical gating. For threshold detection after the decoder, we compared two Mach-Zehnder interferometer (MZI)-based optical thresholding schemes and present results on a new type of electroabsorber-based MZI.
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| 23. |
- Cao, J., et al.
(författare)
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A monolithic ultra-compact inp o-cdma encoder with : Planarization by hvpe regrowth
- 2006
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Ingår i: OFC/NFOEC. - : Optical Society of America. - 1557528020 - 9781557528025
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Konferensbidrag (refereegranskat)abstract
- We report a monolithic, ultra-compact optical-CDMA encoder/decoder photonic chip in InP with surface planarization by low-pressure Hydride-Vapor-Phase-Epitaxy regrowth. The chip consists of an AWG pair and eight electro-optic phase shifters and demonstrated excellent encoding operation.
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| 24. |
- Cao, J., et al.
(författare)
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A monolithic ultra-compact inp o-cdma encoder with : Planarization by hvpe regrowth
- 2005
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Ingår i: Optics InfoBase Conference Papers. - : Optics Info Base, Optical Society of America. - 1557527849 - 9781557527844
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Konferensbidrag (refereegranskat)abstract
- We report a monolithic, ultra-compact optical-CDMA encoder/decoder photonic chip in InP with surface planarization by low-pressure Hydride-Vapor-Phase-Epitaxy regrowth. The chip consists of an AWG pair and eight electro-optic phase shifters and demonstrated excellent encoding operation.
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| 25. |
- Cao, Jing, et al.
(författare)
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Demonstration of Spectral Phase O-CDMA Encoding and Decoding in Monolithically Integrated Arrayed-Waveguide-Grating-Based Encoder
- 2006
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 18:21-24, s. 2602-2604
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Tidskriftsartikel (refereegranskat)abstract
- We report on successful spectral phase encoding and decoding operation in a pair of monolithically integrated InP encoder chips, each consisting of an arrayed waveguide grating (AWG) pair and an eight-channel electrooptic phase shifter array. The monolithic fabrication process includes anisotropic reactive ion etching and planarizing hydride-vapor-phase-epitaxy lateral regrowth to realize buried hetero-waveguide structures in AWGs and phase shifters. Electrooptical modulation in the phase shifter arrays in the encoder chip achieved Walsh-code-based optical code-division multiple access (O-CDMA) encoding and decoding. The matched-code encoding-decoding operation resulted in error-free performance in the presence of an interferer, indicating good potential for O-CDMA network applications.
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