Versatile Integrated PMD Emulation and Compensation Elements

  • Buhl L.
  • Cappuzzo M.
  • Chandrasekhar S.
  • Chen E.
  • Gomez L.
  • Griffin A.
  • Laskowski E.
  • Madsen C.
  • Stulz L.
  • Wong-Foy A.

Abstract: Highly versatile building blocks for PMD emulation and compensation are demonstrated using tunable allpass filters fabricated in 4%-index-contrast planar waveguides. While the allpass filters can approximate any phase response, the complexity in setting the individual filter parameters is minimized by restricting the allpass filter responses to realize a range ...

Intra- and Inter-cell Interference Mitigation Algorithms for High-Speed Packet Downlink in UTRA-TDD

  • Karimi H.

Abstract - Two closely related iterative receivers for mitigation of both intra- and inter-cell interference are considered for HSDPA in UTRA-TDD. The first receiver is based on coherent detection with pre-whitening with respect to the spatio-temporal structure of the interference. The second receiver is based on interference suppression via deterministic ...

Low Linewidth Enhancement Factor of a Type-I Quantum-Cascade Laser

  • Capasso F.
  • Cho A.
  • Chuang S.
  • Gmachl C.
  • Lerttamrab M.
  • Sivco D.

Abstract Experimental results using the amplified spontaneous emission (ASE) spectroscopy of a type-I quantum-cascade (QC) laser are presented. Using the Hakki- Paoli method, the optical gain spectra of the laser are extracted for the wavelength of 8.2 µm at various sub-threshold current levels. The change in refractive index with increased ...

Intensity and Phase Mapping of Guided Light in LiNbO3 Waveguides Using an Interferometric Near-field Scanning Optical Microscope

  • Campillo A.
  • Hsu J.

The design and implementation of a phase sensitive near-field scanning optical microscope incorporating both heterodyne interferometric detection and a phase feedback mechanism are described. Using this microscope we demonstrate a new method for measuring the effective index of the guided mode of a waveguide from the phase images. Two types ...

Crossover and Coexistence of Quasiparticle Excitations in the Fractional Quantum Hall Regime at nu <= 1/3

  • Dennis B.
  • Hirjibehedin C.
  • Pfeiffer L.
  • Pinczuk A.
  • West K.

New low-lying excitations are observed by inelastic light scattering at filling factors nu = p/(phi*p+-1) of the fractional quantum Hall regime with phi = 4. Coexisting with these modes throughout the range nu= 1/3 are phi = 2 excitations seen at 1/3. Both phi = 2 and phi = 4 ...

Temperature dependence and single-mode tuning behavior of Second Harmonic Generation in Quantum Cascade Lasers

  • Belyanin A.
  • Capasso F.
  • Cho A.
  • Gmachl C.
  • Owschimikow N.
  • Peabody M.
  • Sergent A.
  • Sivco D.

Second harmonic generation (SHG) is reported in Quantum Cascade (QC) lasers with active regions that also support nonlinear cascades with large second order nonlinear susceptibility. SHG has been measured from 10 K up to 250 K heat sink temperature, with about 1 mW of nonlinear power at 10 K and ...

MiFi: Managed WiFi for QoS assurance, Fairness and High Throughput of Current IEEE 802.11 Networks with Multiple Access Points

  • Bejerano Y.
  • Bhatia R.

In this paper we present a system for supporting fairness in IEEE 802.11 MAC layer while maximizing the overall throughput. The issue of fairness becomes critical as IEEE 802.11 wireless LAN are widely deployed in nationwide networks linking tens of thousands of "hot-spots" for the purpose of providing both real-time ...

Transparent IP Radio Access for Next Generation Mobile Networks

  • Aghvami H.
  • Alonistioti N.
  • Gazus V.
  • Houssos N.
  • Manner J.
  • Samuel L.
  • Wisely D.
  • Zahariadis T.

Advances in the network architecture, enhancements in the signalling protocols, provisioning of end-to-end Quality of Service (QoS), worldwide seamless mobility and flexible service provision are among the major research challenges towards next generation wireless networks. The integration and interoperability of all these technologies, along with new truly broadband wireless innovations ...

A 5-b 10GS/s A/D Converter for 10-Gb/s Optical Receivers

  • Baeyens Y.
  • Chen Y.
  • Lee J.
  • Link T.
  • Roux P.

In high bit rate optical communication systems operating at 10 Gb/s or beyond, some of the impairments such as chromatic dispersion (CD) and polarization-mode dispersion (PMD) cause degradation of the signal seriously. Electrical domain approach is more desirable than optical compensating techniques because of its potential for compact and cost-effective ...

Quantum Cascade Photonic Crystal Microcavity Surface Emitting Laser

  • Capasso F.
  • Cho A.
  • Colombelli R.
  • Gmachl C.
  • Painter O.
  • Sergent A.
  • Sivco D.
  • Srinivasan K.
  • Tennant D.
  • Troccoli M.

A surface emitting Quantum Cascade injection laser is presented. Direct surface emission is obtained by using a 2D photonic- band-gap structure that simultaneously acts as a microcavity. The approach may allow miniaturization and on-chip-integration of the devices.

Second Harmonic Generation in Periodically Poled GaN

  • Bhardwaj M.
  • Chowdhury A.
  • Ng H.
  • Weimann N.

We report the first experimental demonstration of second harmonic generation in periodically poled GaN by first-order quasi-phase matching. The periodically poled structure was grown by plasma- assisted molecular beam epitaxy. We observed about 9 mW of second harmonic power from a fundamental input laser wavelength of 1658.6 nm with a ...

Star-Shaped Azo based Dipolar Chromophores: Design, Synthesis, Matrix Compatibility, and Electro-optic Activity

  • Bousquet D.
  • Erben C.
  • Gopalan P.
  • Grazul J.
  • Katz H.
  • Mcgee D.
  • Muller D.
  • Olsson Y.
  • Zielinski T.

Three new azo-benzene based push–pull chromophores with dendritic architecture were synthesized as active materials for electro- optic applications. These chromophores were synthesized in 6 to 7 synthetic steps with an overall yield of around 80% and high purity. UV-Vis spectroscopy showed significant influence of the transient dipole moment to the ...

Synthesis of Polymer Dielectric Layers for Organic Thin Film Tansistors via Surface-Initiated ROMP

  • Bao Z.
  • Garfunkel E.
  • Grubbs R.
  • Jiang W.
  • Rutenberg I.
  • Scherman O.

We have shown the feasibility of producing TFTs and capacitors using surface attached ROMP polymers as a layer of dielectric material. Preliminary results indicate that this method will allow for highly tunable materials with desired properties. The ability to grow conformal polymer layers on any topology will be very important ...

Patterning GaN Microstructures by Polarity-Selective Chemical Etching

  • Chowdhury A.
  • Ng H.
  • Parz W.
  • Weimann N.

We have demonstrated GaN microstructures formed by polarity- selective chemical etching in KOH solution. It was found that KOH selectively etches N-polar GaN but not Ga-polar GaN. The polarity-patterned GaN was grown by plasma-assisted molecular beam epitaxy. For intermediate etching times, hexagonal GaN pyramids were formed in the N-polar regions. ...

Jointly Opportunistic Beamforming and Scheduling (JOBS) for Downlink Packet Access

  • Avidor D.
  • Ling J.
  • Papadias C.

In this memo we studied the trade-off between the throughput of a downlink packet access system utilizing opportunistic beamforming and its delay statistics. We have used the probability that the inter-packet delay of a mobile exceeds a certain multiple of its mean delay, as a figure of merit to judge ...

Smooth and Vertical-sidewall InP Etching Using Cl2/N2 Inductively Coupled Plasma

  • Chen Y.
  • Choa F.
  • Kopf R.
  • Leven A.
  • Lin J.
  • Reyes R.
  • Weimann N.
  • Yang Y.

Inductively-coupled plasma operated in the reactive-ion etching mode (ICP-RIE) is used for mesa etching of InP using CL2/N2 chemistry with a Ni metal mask. Etch rate of approximately 140nm/min with very smooth and vertical sidewalls is obtained at a DC bias of 120V. The effects of temperature, gas flow, chamber ...

Effect of Dislocations on Local Transconductance in AlGaN/GaN Heterostructures as Imaged by Scanning Gate Microscopy

  • Hsu J.
  • Lang D.
  • Manfra M.
  • Mitrofanov O.
  • Molnar R.
  • Schrey F.
  • Weimann N.
  • West K.

The spatial variation of transconductance in AlGaN/GaN heterostructures was mapped using the conducting tip of an atomic force microscope to locally modulate the two-dimensional electron gas (2DEG) while monitoring the change in the drain current as a function of tip position. A spatial resolution of 100 nm was obtained. This ...

Integrated band demultiplexer using waveguide grating routers

  • Doerr C.
  • Pafchek R.
  • Stulz L.

We present a novel band demultiplexer design for planar lightwave circuits. It consists of two perfectly sampled waveguide grating routers connected by sets of equal path length waveguides separated on one side. Its advantages are compactness, sharp passband corners, and a lack of chromatic dispersion.

Waveguide lenses using multimode interference for low-loss slab propagation

  • Stuart H.

It is shown that a nearly ideal two-dimensional focusing Gaussian beam can be synthesized using a linear combination of the two lowest order even modes of an optical waveguide. This property can be used to couple laterally guided modes across slab waveguide regions with very low loss. The technique is ...

A High-Gain InP D-HBT Driver Amplifier with 50 GHz Bandwidth and 10 Vpp Differential Output Swing at 40 Gb/s

  • Baeyens Y.
  • Chen Y.
  • Houtsma V.
  • Kopf R.
  • Paschke P.
  • Roux P.
  • Weimann N.
  • Weiner J.
  • Yang Y.

A high-performance and compact 40 Gb/s driver amplifier was realized in a 1.2 um emitter double-heterojunction InGaAs/InP HBT (D-HBT) technology. The 2-stage differential driver features a lumped input and fully distributed output stage and delivers more than 10 Vpp output swing at 40 Gb/s with 700 fs RMS jitter and ...