| 251. |
- Stattin, Martin, 1983, et al.
(författare)
-
Graphene as transparent electrode for GaN-based VCSELs
- 2012
-
Ingår i: International Workshop on Nitride Semiconductors 2012, October 14-19, 2012, Sapporo, Japan. ; , s. ThP-OD-34-
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 252. |
- Stattin, Martin, 1983, et al.
(författare)
-
Waveguides for nitride based quantum cascade lasers
- 2011
-
Ingår i: Physica Status Solidi (C) Current Topics in Solid State Physics. - : Wiley. - 1610-1642 .- 1862-6351. ; 8:7-8, s. 2357-2359
-
Tidskriftsartikel (refereegranskat)abstract
- Waveguide designs for AlGaN-based near-infrared quantum cascade lasers are investigated using a finite-difference method mode solver. Because of the negligibly small refractive index difference between the AlN/GaN/AlGaN gain region and the surrounding AlGaN current injection and extraction layers, a low refractive index substrate (sapphire) and a low refractive index dielectric (SiO2) are used for vertical confinement of the optical field. A ridge waveguide with an off-center contact metallization is used for lateral confinement. The off-center contact allows for the propagation of a TM mode with low metal induced loss and sufficient optical confinement in the gain region. A viable waveguide design with a metal-induced loss of 6.1 cm-1 and a confinement factor of 0.52 is demonstrated.
|
|
| 253. |
- Stattin, Martin, 1983, et al.
(författare)
-
Waveguides for Nitride Based Quantum Cascade Lasers
- 2010
-
Ingår i: International Workshop on Nitride Semiconductors (IWN2010), Tampa, Florida, U.S.A., September 19 – 24, 2010.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
|
|
| 254. |
|
|
| 255. |
- Stattin, Martin, 1983, et al.
(författare)
-
ZnO/AlN Clad Waveguides for AlGaN-Based Quantum Cascade Lasers
- 2013
-
Ingår i: Japanese Journal of Applied Physics. - 1347-4065 .- 0021-4922. ; 52:5, s. 054001 -
-
Tidskriftsartikel (refereegranskat)abstract
- Waveguide designs for AlGaN-based near-infrared quantum cascade lasers are proposed and analyzed using optical mode solvers. Because of the poor electrical conductivity, AlN is not a suitable cladding material for the AlN/GaN/AlGaN gain region. Instead we propose the use of ZnO as a conductive top cladding and to embed the gain region between AlGaN current injection and extraction regions so that an AlN substrate can be used as the lower cladding. We also examine the use of an AlN template on a SiC substrate and find that it can also provide sufficient mode confinement with negligible radiation loss into the SiC substrate. We identify a single mode ridge waveguide design with reasonable mode confinement (40%) and loss (39 cm-1).
|
|
| 256. |
- Sun, Jie, 1977, et al.
(författare)
-
Direct Chemical Vapor Deposition of Large-Area Carbon Thin Films on Gallium Nitride for Transparent Electrodes: A First Attempt
- 2012
-
Ingår i: IEEE Transactions on Semiconductor Manufacturing. - : Institute of Electrical and Electronics Engineers (IEEE). - 0894-6507 .- 1558-2345. ; 25:3, s. 494-501
-
Tidskriftsartikel (refereegranskat)abstract
- Direct formation of large-area carbon thin films on gallium nitride by chemical vapor deposition without metallic catalysts is demonstrated. A high flow of ammonia is used to stabilize the surface of the GaN (0001)/sapphire substrate during the deposition at 950 degrees C. Various characterization methods verify that the synthesized thin films are largely sp(2) bonded, macroscopically uniform, and electrically conducting. The carbon thin films possess optical transparencies comparable to that of exfoliated graphene. This paper offers a viable route toward the use of carbon-based materials for future transparent electrodes in III-nitride optoelectronics, such as GaN-based light emitting diodes and laser diodes.
|
|
| 257. |
|
|
| 258. |
- Szczerba, Krzysztof, 1985, et al.
(författare)
-
30 Gbps 4-PAM transmission over 200m of MMF using an 850 nm VCSEL
- 2011
-
Ingår i: Optics Express. - 1094-4087 .- 1094-4087. ; 19:26, s. B203-B208
-
Tidskriftsartikel (refereegranskat)abstract
- We present high speed real time, error free 4-PAMtransmissionfor short range optical links based on a VCSEL operating at 850 nm, a multimode fibre and a simple intensity detector. Transmission speeds of 25 Gbps and 30 Gbps are demonstrated, and the maximum fibre reaches were 300 m and 200 m, respectively. The 4-PAM is also compared with OOK transmission at 25 Gbps, and we find that at this bit rate 4-PAM increases the error free transmission distance in the multimode fibre by 100 m, compared to OOK.
|
|
| 259. |
- Szczerba, Krzysztof, 1985, et al.
(författare)
-
30 Gbps 4-PAM transmission over 200m of MMF using an 850 nm VCSEL
- 2011
-
Ingår i: European Conference and Exposition on Optical Communications, ECOC. - 2162-2701. - 9781557529312 ; , s. 1-3
-
Konferensbidrag (refereegranskat)abstract
- Real time, error free 4-PAM transmission at 25 Gbps and 30 Gbps over 300 m and200m of multimode fiber, respectively, using a VCSEL operating at the wavelength of 850 nm.
|
|
| 260. |
- Szczerba, Krzysztof, 1985, et al.
(författare)
-
35.2 Gbps 8-PAM transmission over 100 m of MMF using an 850 nm VCSEL
- 2013
-
Ingår i: Proc. European Conference on Optical Communication (ECOC). - : Institution of Engineering and Technology. - 9781849197595 ; 2013:622 CP, s. 744-746
-
Konferensbidrag (refereegranskat)abstract
- We report experimental demonstration of 8-PAM transmission using an 850 nm VCSEL and 100 m of OM4-type MMF. The 8-level driving signal was generated using a 3-bit DAC, the error rates were measured in real time using a conventional error analyzer. Maximum uncoded bit rate was 37.5 Gbps, which corresponds to 35.2 Gbps with 7% FEC overhead.
|
|
