The Experts below are selected from a list of 38961 Experts worldwide ranked by ideXlab platform
John E. Bowers - One of the best experts on this subject based on the ideXlab platform.
-
a distributed feedback silicon evanescent laser
Optics Express, 2008Co-Authors: Alexander W Fang, Erica Lively, Di Liang, John E. BowersAbstract:We report an electrically pumped distributed feedback silicon evanescent laser. The laser operates continuous wave with a single mode output at 1600 nm. The laser threshold is 25 mA with a Maximum output power of 5.4 mW at 10 °C. The Maximum Operating Temperature and minimum line width of the laser are 50 °C, and 3.6 MHz, respectively.
-
integrated algainas silicon evanescent racetrack laser and photodetector
Proceedings of SPIE the International Society for Optical Engineering, 2007Co-Authors: Alexander W Fang, Hyundai Park, Richard Jones, Oded Cohen, Omri Raday, Mario J Paniccia, John E. BowersAbstract:Recently, AlGaInAs-silicon evanescent lasers have been demonstrated as a method of integrating active photonic devices on a silicon based platform. This hybrid waveguide architecture consists of III-V quantum wells bonded to silicon waveguides. The self aligned optical mode leads to a bonding process that is manufacturable in high volumes. Here give an overview of a racetrack resonator laser integrated with two photo-detectors on the hybrid AlGaInAs-silicon evanescent device platform. Unlike previous demonstrations of hybrid AlGaInAs-silicon evanescent lasers, we demonstrate an on-chip racetrack resonator laser that does not rely on facet polishing and dicing in order to define the laser cavity. The laser runs continuous-wave (c.w.) at 1590 nm with a threshold of 175 mA, has a Maximum total output power of 29 mW and a Maximum Operating Temperature of 60 C. The output of this laser light is directly coupled into a pair of on chip hybrid AlGaInAs-silicon evanescent photodetectors used to measure the laser output.
-
integrated algainas silicon evanescent race track laser and photodetector
Optics Express, 2007Co-Authors: Alexander W Fang, Hyundai Park, Richard Jones, Oded Cohen, Omri Raday, Mario J Paniccia, John E. BowersAbstract:Here we report a racetrack resonator laser integrated with two photo-detectors on the hybrid AlGaInAs-silicon evanescent device platform. Unlike previous demonstrations of hybrid AlGaInAs-silicon evanescent lasers, we demonstrate an on-chip racetrack resonator laser that does not rely on facet polishing and dicing in order to define the laser cavity. The laser runs continuous-wave (c.w.) at 1590 nm with a threshold of 175 mA, has a Maximum total output power of 29 mW and a Maximum Operating Temperature of 60 C. The output of this laser light is directly coupled into a pair of on chip hybrid AlGaInAs-silicon evanescent photodetectors used to measure the laser output. OCIS codes: (140.5960) Semiconductor lasers; (250.5300) Photonic integrated circuits.
-
electrically pumped hybrid algainas silicon evanescent laser
Optics Express, 2006Co-Authors: Alexander W Fang, Hyundai Park, Richard Jones, Oded Cohen, Mario J Paniccia, John E. BowersAbstract:An electrically pumped light source on silicon is a key element needed for photonic integrated circuits on silicon. Here we report an electrically pumped AlGaInAs-silicon evanescent laser architecture where the laser cavity is defined solely by the silicon waveguide and needs no critical alignment to the III-V active material during fabrication via wafer bonding. This laser runs continuous-wave (c.w.) with a threshold of 65 mA, a Maximum output power of 1.8 mW with a differential quantum efficiency of 12.7 % and a Maximum Operating Temperature of 40 °C. This approach allows for 100’s of lasers to be fabricated in one bonding step, making it suitable for high volume, low-cost, integration. By varying the silicon waveguide dimensions and the composition of the III-V layer, this architecture can be extended to fabricate other active devices on silicon such as optical amplifiers, modulators and photo-detectors.
Edmund H. Linfield - One of the best experts on this subject based on the ideXlab platform.
-
silver based surface plasmon waveguide for terahertz quantum cascade lasers
Optics Express, 2018Co-Authors: Lianhe Li, Paul Dean, Li Chen, A. Giles Davies, A Valavanis, Joshua R Freeman, Mark C Rosamond, Edmund H. LinfieldAbstract:Terahertz-frequency quantum cascade lasers (THz QCLs) based on ridge waveguides incorporating silver waveguide layers have been investigated theoretically and experimentally, and compared with traditional gold-based devices. The threshold gain associated with silver-, gold- and copper-based devices, and the effects of titanium adhesion layers and top contact layers, in both surface-plasmon and double-metal waveguide geometries, have been analysed. Our simulations show that silver-based waveguides yield lower losses for THz QCLs across all practical Operating Temperatures and frequencies. Experimentally, QCLs with silver-based surface-plasmon waveguides were found to exhibit higher Operating Temperatures and higher output powers compared to those with identical but gold-based waveguides. Specifically, for a three-well resonant phonon active region with a scaled oscillator strength of 0.43 and doping density of 6.83 × 1015 cm−3, an increase of 5 K in the Maximum Operating Temperature and 40% increase in the output power were demonstrated. These effects were found to be dependent on the active region design, and greater improvements were observed for QCLs with a larger radiative diagonality. Our results indicate that silver-based waveguide structures could potentially enable THz QCLs to operate at high Temperatures.
-
terahertz quantum cascade lasers with 1 w output powers
Electronics Letters, 2014Co-Authors: Li Chen, Paul Dean, A. Giles Davies, Jingxuan Zhu, Jim Freeman, A Valavanis, Edmund H. LinfieldAbstract:Terahertz (THz) frequency quantum cascade lasers emitting peak powers of >1 W from a single facet in the pulsed mode are demonstrated. The active region is based on a bound-to-continuum transition with a one-well injector, and is embedded into a surface-plasmon waveguide. The lasers emit at a frequency of ∼3.4 THz and have a Maximum Operating Temperature of 123 K. The Maximum measured emitted powers are ∼1.01 W at 10 K and ∼420 mW at 77 K, with no correction made to allow for the optical collection efficiency of the apparatus.
-
terahertz quantum cascade lasers with copper metal metal waveguides Operating up to 178 k
Optics Express, 2008Co-Authors: Mikhail A Belkin, Federico Capasso, Jonathan A Fan, Sahand Hormoz, S P Khanna, Mohamed Lachab, Andrew Davies, Edmund H. LinfieldAbstract:We report terahertz quantum cascade lasers Operating in pulsed mode at an emission frequency of 3 THz and up to a Maximum Temperature of 178 K. The improvement in the Maximum Operating Temperature is achieved by using a three-quantum-well active region design with resonant-phonon depopulation and by utilizing copper, instead of gold, for the cladding material in the metal-metal waveguides.
-
far infrared λ 87 μm bound to continuum quantum cascade lasers Operating up to 90 k
Applied Physics Letters, 2003Co-Authors: Giacomo Scalari, Edmund H. Linfield, Jerome Faist, Lassaad Ajili, Harvey E Beere, D A Ritchie, Giles DaviesAbstract:We report terahertz frequency (3.5 THz, λ≃87 μm) emission from quantum-cascade lasers employing a bound-to-continuum transition in the active region. The Maximum Operating Temperature is in excess of 90 K. Peak powers of 20 mW at 20 K and 10 mW at 77 K are achieved. The same devices show continuous-wave operation up to 55 K with measured optical powers of 15 mW at 10 K.
-
high performance continuous wave operation of superlattice terahertz quantum cascade lasers
Applied Physics Letters, 2003Co-Authors: R Kohler, Edmund H. Linfield, Alessandro Tredicucci, Harvey E Beere, D A Ritchie, Fabio Beltram, Giles A Davies, S S Dhillon, Carlo SirtoriAbstract:The cw operation of chirped-superlattice quantum-cascade lasers emitting at λ∼67 μm (4.4 THz) is analyzed. Collected (min. 33% efficiency) output powers of 4 mW per facet are measured at liquid helium Temperatures and a Maximum Operating Temperature of 48 K is reached. Under pulsed excitation at duty cycles of 0.5%–1%, slightly higher (10%) peak powers are reached, and the device can be operated up to 67 K. Low threshold current densities of 165 and 185 A cm−2 are observed in pulsed and cw operation, respectively. The operation of the laser is examined using the Hakki–Paoli technique to estimate the net gain of the structure.
Jerome Faist - One of the best experts on this subject based on the ideXlab platform.
-
ingaas alingaas thz quantum cascade lasers Operating up to 195 k in strong magnetic field
New Journal of Physics, 2015Co-Authors: Federico Valmorra, Mattias Beck, Giacomo Scalari, K Ohtani, Jerome FaistAbstract:Terahertz quantum cascade lasers based on InGaAs wells and quaternary AlInGaAs barriers were measured in magnetic field. This study was carried out on a four-quantum-well active-region design with photon energy of 14.3 meV processed with both Au and Cu waveguides. The heterostructure operates up to 148 K at B = 0 T in a Cu waveguide. The complete magneto-spectroscopic study allowed the comparison of emission and transport data. Increasing the magnetic field, the low effective mass of the InGaAs wells allowed us to reach the very strong confinement regime. At B = 12 T, where the cyclotron transition is almost resonant with the LO-phonon, we recorded a Maximum Operating Temperature of 195 K for the devices with Cu waveguide. Additional lasing at 5.9 meV was detected for magnetic fields between 7.3 and 7.7 T.
-
far infrared λ 87 μm bound to continuum quantum cascade lasers Operating up to 90 k
Applied Physics Letters, 2003Co-Authors: Giacomo Scalari, Edmund H. Linfield, Jerome Faist, Lassaad Ajili, Harvey E Beere, D A Ritchie, Giles DaviesAbstract:We report terahertz frequency (3.5 THz, λ≃87 μm) emission from quantum-cascade lasers employing a bound-to-continuum transition in the active region. The Maximum Operating Temperature is in excess of 90 K. Peak powers of 20 mW at 20 K and 10 mW at 77 K are achieved. The same devices show continuous-wave operation up to 55 K with measured optical powers of 15 mW at 10 K.
-
gaas alxga1 xas quantum cascade lasers
Applied Physics Letters, 1998Co-Authors: C Sirtori, P Kruck, S Barbieri, Philippe Collot, J Nagle, Mattias Beck, Jerome Faist, U OesterleAbstract:A unipolar injection quantum cascade (QC) laser grown in an AlGaAs/GaAs material system by molecular beam epitaxy, is reported. The active material is a 30 period sequence of injectors/active regions made from Al0.33Ga0.67As/GaAs-coupled quantum wells. For this device a special waveguide design, which complies with a GaAs heavily doped substrate and very short Al0.90Ga0.10As cladding layers, has been optimized. At a heat-sink Temperature of 77 K, the laser emission wavelength is 9.4 μm with peak optical power exceeding 70 mW and the threshold current density is 7.3 kA/cm2. The Maximum Operating Temperature is 140 K. This work experimentally demonstrates the general validity of QC laser principles by showing laser action in a heterostructure material different from the one used until now.
-
long wavelength 8 11 5 µm semiconductor lasers with waveguides based on surface plasmons
Optics Letters, 1998Co-Authors: C Sirtori, Jerome Faist, Claire F Gmachl, Federico Capasso, Deborah L Sivco, Albert L Hutchinson, A Y ChoAbstract:Laser waveguides based on surface plasmons at a metal–semiconductor interface have been demonstrated by use of quantum cascade (QC) lasers emitting in the 8–11.5?µm wavelength range. The guided modes are transverse magnetic polarized surface waves that propagate at the metal (Pd or Ti–Au)–semiconductor interface between the laser top contact and the active region without the necessity for waveguide cladding layers. The resultant structure has the advantages of a strong decrease in the total layer thickness and a higher confinement factor of the laser-active region compared with those of a conventional layered semiconductor waveguide, and strong coupling to the active material, which could be used in devices such as distributed-feedback lasers. These advantages have to be traded against the disadvantage of increased absorption losses. A peak output power exceeding 25??mW at 90??K and a Maximum Operating Temperature of 150??K were measured for a QC laser with an emission wavelength ??8 µm. At ??11.5 µm the peak power levels are several milliwatts and the Maximum Operating Temperature is 110??K.
-
quantum cascade laser Temperature dependence of the performance characteristics and high t0 operation
Applied Physics Letters, 1994Co-Authors: Jerome Faist, C Sirtori, Federico Capasso, A L Hutchinson, Deborah L Sivco, S N G Chu, Alfred Y ChoAbstract:The design and Temperature dependence of the performance characteristics of a quantum cascade intersubband laser Operating pulsed in the midinfrared (λ≂4.3 μm) are reported. The threshold current density varies exponentially with Temperature [exp(T/T0)] from ≊6.0 kA/cm2 at 50 K to ≊9.3 kA/cm2 up to the Maximum Operating Temperature (125 K) with a T0∼112 K. This weak Temperature dependence, compared to interband lasers Operating at similar wavelengths, is due to the intersubband nature of the laser transition, to the physics of optical phonons scattering, and to the negligible intersubband Auger transition rates. The measured peak optical power varies from 32 mW at 10 K to 18 mW at 80 K for a 1.2‐mm cavity length. The measured slope efficiency is 52 mW/A at 80 K which corresponds to an estimated differential quantum efficiency of ≂3.4×10−2 per facet per stage.
Alexander W Fang - One of the best experts on this subject based on the ideXlab platform.
-
a distributed feedback silicon evanescent laser
Optics Express, 2008Co-Authors: Alexander W Fang, Erica Lively, Di Liang, John E. BowersAbstract:We report an electrically pumped distributed feedback silicon evanescent laser. The laser operates continuous wave with a single mode output at 1600 nm. The laser threshold is 25 mA with a Maximum output power of 5.4 mW at 10 °C. The Maximum Operating Temperature and minimum line width of the laser are 50 °C, and 3.6 MHz, respectively.
-
integrated algainas silicon evanescent racetrack laser and photodetector
Proceedings of SPIE the International Society for Optical Engineering, 2007Co-Authors: Alexander W Fang, Hyundai Park, Richard Jones, Oded Cohen, Omri Raday, Mario J Paniccia, John E. BowersAbstract:Recently, AlGaInAs-silicon evanescent lasers have been demonstrated as a method of integrating active photonic devices on a silicon based platform. This hybrid waveguide architecture consists of III-V quantum wells bonded to silicon waveguides. The self aligned optical mode leads to a bonding process that is manufacturable in high volumes. Here give an overview of a racetrack resonator laser integrated with two photo-detectors on the hybrid AlGaInAs-silicon evanescent device platform. Unlike previous demonstrations of hybrid AlGaInAs-silicon evanescent lasers, we demonstrate an on-chip racetrack resonator laser that does not rely on facet polishing and dicing in order to define the laser cavity. The laser runs continuous-wave (c.w.) at 1590 nm with a threshold of 175 mA, has a Maximum total output power of 29 mW and a Maximum Operating Temperature of 60 C. The output of this laser light is directly coupled into a pair of on chip hybrid AlGaInAs-silicon evanescent photodetectors used to measure the laser output.
-
integrated algainas silicon evanescent race track laser and photodetector
Optics Express, 2007Co-Authors: Alexander W Fang, Hyundai Park, Richard Jones, Oded Cohen, Omri Raday, Mario J Paniccia, John E. BowersAbstract:Here we report a racetrack resonator laser integrated with two photo-detectors on the hybrid AlGaInAs-silicon evanescent device platform. Unlike previous demonstrations of hybrid AlGaInAs-silicon evanescent lasers, we demonstrate an on-chip racetrack resonator laser that does not rely on facet polishing and dicing in order to define the laser cavity. The laser runs continuous-wave (c.w.) at 1590 nm with a threshold of 175 mA, has a Maximum total output power of 29 mW and a Maximum Operating Temperature of 60 C. The output of this laser light is directly coupled into a pair of on chip hybrid AlGaInAs-silicon evanescent photodetectors used to measure the laser output. OCIS codes: (140.5960) Semiconductor lasers; (250.5300) Photonic integrated circuits.
-
electrically pumped hybrid algainas silicon evanescent laser
Optics Express, 2006Co-Authors: Alexander W Fang, Hyundai Park, Richard Jones, Oded Cohen, Mario J Paniccia, John E. BowersAbstract:An electrically pumped light source on silicon is a key element needed for photonic integrated circuits on silicon. Here we report an electrically pumped AlGaInAs-silicon evanescent laser architecture where the laser cavity is defined solely by the silicon waveguide and needs no critical alignment to the III-V active material during fabrication via wafer bonding. This laser runs continuous-wave (c.w.) with a threshold of 65 mA, a Maximum output power of 1.8 mW with a differential quantum efficiency of 12.7 % and a Maximum Operating Temperature of 40 °C. This approach allows for 100’s of lasers to be fabricated in one bonding step, making it suitable for high volume, low-cost, integration. By varying the silicon waveguide dimensions and the composition of the III-V layer, this architecture can be extended to fabricate other active devices on silicon such as optical amplifiers, modulators and photo-detectors.
Jin Kuk Kim - One of the best experts on this subject based on the ideXlab platform.
-
properties of new nanocomposite triblock copolymer gels based on expandable graphite
Polymer Engineering and Science, 2008Co-Authors: Marissa A Paglicawan, Jin Kuk KimAbstract:In this work, we investigated the effect of expandable graphite (EG) on the property of triblock copolymer prepared from a poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) imbibed with an EB-compatible hydrocarbon oil. The rheological properties showed that at a Temperature between 30 and 40°C below the gel point, the triblock copolymer gels had a dynamic storage modulus (G′) greater than loss modulus (G‵), thereby indicating that at ambient Temperature, a physical network is still present in spite of the addition of nanoparticles. Dynamic rheological measurements of the resultant nanocomposite triblock copolymer gels confirmed that the addition of EG affects the linear viscoelastic properties and Maximum Operating Temperature of the parent triblock copolymer gels. The mechanical properties showed only marginal increase, which can be attributed to the poor dispersion that leads to agglomeration of particle into micrometer size stacks, and thus the particles behave only as inorganic fillers. The morphology and X-ray diffraction revealed that the EG used to generate nanocomposite triblock copolymer gels is dispersed generally within the swollen copolymer and/or solvent. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
-
properties of new nanocomposite triblock copolymer gels based on expandable graphite
International Conference on Parallel Processing, 2008Co-Authors: Marissa A Paglicawan, Jin Kuk KimAbstract:In this work, we investigated the effect of expandable graphite (EG) on the property of triblock copolymer prepared from a poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS) imbibed with an EB-compatible hydrocarbon oil. The rheological properties showed that at a Temperature between 30 and 40°C below the gel point, the triblock copolymer gels had a dynamic storage modulus (G') greater than loss modulus (G"), thereby indicating that at ambient Temperature, a physical network is still present in spite of the addition of nanoparticles. Dynamic rheological measurements of the resultant nanocomposite triblock copolymer gels confirmed that the addition of EG affects the linear viscoelastic properties and Maximum Operating Temperature of the parent triblock copolymer gels. The mechanical properties showed only marginal increase, which can be attributed to the poor dispersion that leads to agglomeration of particle into micrometer size stacks, and thus the particles behave only as inorganic fillers. The morphology and X-ray diffraction revealed that the EG used to generate nanocomposite triblock copolymer gels is dispersed generally within the swollen copolymer and/or solvent.