| 1. |
- Akram, Nadeem, 1971-, et al.
(författare)
-
Experimental characterization of high-speed 1.55 mu m buried heterostructure InGaAsP/InGaAlAs quantum-well lasers
- 2009
-
Ingår i: Journal of the Optical Society of America. B, Optical physics. - 0740-3224 .- 1520-8540. ; 26:2, s. 318-327
-
Tidskriftsartikel (refereegranskat)abstract
- Detailed experimental characterization is performed for 1550 nm semi-insulating regrown buried heterostructure Fabry-Perot (FP) lasers having 20 InGaAsP/InGaAlAs strain-balanced quantum wells (QWs) in the active region. Light-current-voltage performance, electrical impedance, small-signal response below and above threshold, amplified spontaneous emission spectrum below threshold and relative intensity noise spectrum are measured. Different laser parameters such as external differential quantum efficiency eta(d), background optical loss alpha(i), K-factor, D-factor, characteristic temperature T-0, differential gain dg/dn, gain-compression factor epsilon, carrier density versus current, differential carrier lifetime tau(d), optical gain spectrum below threshold, and chirp parameter alpha are extracted from these measurements. The FP lasers exhibited a high T-0 (78-86.5 degrees C) and very high-resonance frequency (23.7 GHz). The results indicate that appropriately designed lasers having a large number of InGaAsP well/InGaAlAs barrier QWs with shallow valence-band discontinuity can be useful for un-cooled high-speed direct-modulated laser applications.
|
|
| 2. |
- Akram, Nadeem, 1971-, et al.
(författare)
-
High-Speed Performance of 1.55 µm Buried Hetero-Structure Lasers with 20 InGaAsP/InGaAlAs Quantum-Wells
- 2006
-
Ingår i: 2006 European Conference on Optical Communications Proceedings, ECOC 2006. - : IEEE. - 9782912328397 ; , s. 1-2
-
Konferensbidrag (refereegranskat)abstract
- 1550 nm re-grown FP lasers having 20 InGaAsP/InGaAlAs strain-balanced QWs exhibit low threshold current density, high T0 (78.0 #x000B0;C) and high resonance frequency (24 GHz) indicating that a large number of shallow barrier QWs are attractive for un-cooled high-speed direct-modulation applications.
|
|
| 3. |
- Anand, Srinivasan, et al.
(författare)
-
InP-based two dimensional photonic crystals : A material and processing perspective
- 2008
-
Ingår i: ICTON 2008. - NEW YORK : IEEE. - 9781424426256 ; , s. 25-25
-
Konferensbidrag (refereegranskat)abstract
- The talk will address fabrication and characterization of InP-based two-dimensional (2D) photonic crystals (PhCs). The emphasis will be on material and processing issues. In particular, high aspect ratio etching of PhCs in the InP-based materials will be discussed, including feature-size dependent etching and its impact on the optical properties of PhCs. The physical basis for modification of carrier lifetimes of quantum wells in etched PhCs due to the so-called accumulated side-wall damage and methods to control carrier lifetimes relevant for emitter and switching applications will be discussed. Fundamental investigations of carrier transport across PhC structures will be reported and a new method to determine the etched side-wall Surface potential will be demonstrated.
|
|
| 4. |
- Anand, Srinivasan, et al.
(författare)
-
Towards realization of high quality 2D-photonic crystals in InP/GaInAsP/InP
- 2004
-
Ingår i: 2004 International Conference on Indium Phosphide and Related Materials, Conference Proceedings. - 0780385950 ; , s. 311-313
-
Konferensbidrag (refereegranskat)abstract
- Two-dimensional photonic crystals (PhCs) were etched into InP/GaInAsP/InP planar waveguides using chlorine based chemical assisted ion beam etching (CAIBE). Etching mechanisms and process parameters crucial for high quality PhC definition are discussed, with special attention to the lag-effect. The processed PhCs were optically characterized by measuring transmission through simple slabs and one-dimensional cavities. The optical properties inside the photonic bandgap are much better compared to both previously reported CAME results and results obtained with other etching methods. In particular, we measured a record quality factor of 310 for one-dimensional cavities fabricated in this material system.
|
|
| 5. |
- Aubin, G., et al.
(författare)
-
Highly dispersive photonic crystal-based guiding structures
- 2006
-
Ingår i: CLEO/QELS 2006. - : Optical Society of America. - 1557528136 - 9781557528131 ; , s. 972-974
-
Konferensbidrag (refereegranskat)abstract
- Propagating modes supported by Photonic-Crystal guiding structures can demonstrate very high group velocity dispersion close to a cut-off. We investigate here the wavelength dependence of the dispersion for different Photonic Crystal structures.
|
|
| 6. |
- Benyattou, T., et al.
(författare)
-
Optical Bloch waves studied by near optical field microscopy
- 2005
-
Ingår i: Journal of the Korean Physical Society. - 0374-4884 .- 1976-8524. ; 47, s. S72-S75
-
Tidskriftsartikel (refereegranskat)abstract
- Photonic bandgap structures are very promising for the integration of optical function at the nanoscale level and particularly 2D structures perforated on a slab waveguide. In this context, photonic crystal waveguides obtained by removing rows of holes in the periodic structure are very interesting. We will present here, results of near field optical microscopy conducted on PCW. With a Fourier transform analysis of the image, we can image the Bloch waves propagating in the waveguide. The results are compared to FDTD simulations and we will show that the images obtained correspond to the electric field. Such result allows us to study the interaction of the optical tip with the electromagnetic field. 2D FDTD simulations of 1D photonic crystal interaction with a SNOM tip is presented. The results obtained confirm that the SNOM signal is mainly related to the electric field.
|
|
| 7. |
- Berrier, Audrey, et al.
(författare)
-
Accumulated sidewall damage in dry etched photonic crystals
- 2009
-
Ingår i: Journal of Vacuum Science & Technology B. - : American Vacuum Society. - 1071-1023 .- 1520-8567. ; 27:4, s. 1969-1975
-
Tidskriftsartikel (refereegranskat)abstract
- Evidence for accumulated damage is provided by investigating the effect of etch duration on the carrier lifetime of an InGaAsP quantum well (QW) inside the InP-based photonic crystal (PhC) structures. It is found that once the quantum well is etched through, additional etching reduces the carrier lifetimes from 800 to 70 ps. The surface recombination velocity (SRV) at the exposed hole sidewalls is determined from the measured carrier lifetimes of the PhC fields with different lattice parameters. The observed variation in the SRV with etch duration also confirms the presence of accumulated sidewall damage. It increases from 6x10(3) to 1.2x10(5) cm s(-1) as the etching time increases from 3 to 50 min. A geometric model based on sputtering theory and on the evolution of the hole shape is developed to explain the accumulation of sidewall damage. The model is used to estimate the number of impact events from sputtered species reaching the QW sidewalls, and the variation in the accumulated impact events with etch duration is shown to be qualitatively consistent with the experimental observations. Finally, the results suggest a new method for tailoring the carrier lifetimes in PhC membrane structures.
|
|
| 8. |
- Berrier, Audrey, et al.
(författare)
-
Bloch mode excitation in two-dimensional photonic crystals imaged by Fourier optics
- 2009
-
Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 79:16, s. 165116-1-165116-6
-
Tidskriftsartikel (refereegranskat)abstract
- Coupling into the Bloch modes of a two-dimensional photonic crystal (PhC) field is investigated by Fourier optics. The PhC was designed to operate in the second band above the air-light line, close to the autocollimation regime for TE polarization. The sample was fabricated in an InP-based heterostructure and an access ridge waveguide provides in-plane excitation of the PhC. The spatial Fourier transform of the field maps obtained from finite-difference time-domain simulations and those calculated by plane-wave expansion are compared to the experimentally obtained equifrequency surfaces (EFS). The shape of the imaged EFS and its variation with the excitation wavelength is shown to be consistent with the theoretical simulations. Finally, the results indicate that if combined with different excitation geometries, Fourier optics can be a powerful technique to assess photonic crystal devices and to design efficient structures.
|
|
| 9. |
- Berrier, Audrey, et al.
(författare)
-
Carrier transport through a dry-etched InP-based two-dimensional photonic crystal
- 2007
-
Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 101:12, s. 123101-1-123101-6
-
Tidskriftsartikel (refereegranskat)abstract
- The electrical conduction across a two-dimensional photonic crystal (PhC) fabricated by Ar/Cl-2 chemically assisted ion beam etching in n-doped InP is influenced by the surface potential of the hole sidewalls, modified by dry etching. Carrier transport across photonic crystal fields with different lattice parameters is investigated. For a given lattice period the PhC resistivity increases with the air fill factor and for a given air fill factor it increases as the lattice period is reduced. The measured current-voltage characteristics show clear ohmic behavior at lower voltages followed by current saturation at higher voltages. This behavior is confirmed by finite element ISE TCAD (TM) simulations. The observed current saturation is attributed to electric-field-induced saturation of the electron drift velocity. From the measured and simulated conductance for the different PhC fields we show that it is possible to determine the sidewall depletion region width and hence the surface potential. We find that at the hole sidewalls the etching induces a Fermi level pinning at about 0.12 eV below the conduction band edge, a value much lower than the bare InP surface potential. The results indicate that for n-InP the volume available for conduction in the etched PhCs approaches the geometrically defined volume as the doping is increased.
|
|
| 10. |
- Berrier, Audrey, et al.
(författare)
-
Characterization of the feature-size dependence in Ar/Cl2 chemically assisted ion beam etching of InP-based photonic crystal devices
- 2007
-
Ingår i: Journal of Vacuum Science & Technology B. - : American Vacuum Society. - 1071-1023 .- 1520-8567. ; 25:1, s. 1-10
-
Tidskriftsartikel (refereegranskat)abstract
- The authors address feature-size dependence in Ar/Cl-2, chemically assisted ion beam etching (CAIBE) in the context of the fabrication of photonic crystal (PhC) structures. They systematically investigate the influence of various parameters such as hole diameter (115-600 nm), etch duration (10-60 min), and ion beam energy (300-600 eV) on PhC etching in InP with Ar/Cl-2, CAIBE. For a 60 min etching at an Ar-ion energy of 400 eV, the authors report an etch depth of 5 mu m for hole diameters d larger than 300 nm; the etch depth is in excess of 3 mu m for d larger than 200 nm. The evolution of roughness at the bottom of the etched holes and its dependence on hole size and etching conditions,is discussed. The physical mechanism of the observed feature-size dependent etching (FSDE) is then discussed and the effect of the process parameters is qualitatively understood using a model combining the effect of ion sputtering and surface chemical reactions. Finally, the effect of FSDE on the PhC optical properties is assessed by measuring the quality factor of one-dimensional Fabry-Perot PhC cavities. The measured quality factors show a clear trend with the etch depth: the cavity Q increases as the etch depth increases.
|
|
