Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Performance Optimization of GaAs-Based Vertical-Cavity Surface-Emitting Transistor-Lasers
KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
KTH, School of Information and Communication Technology (ICT), Integrated Devices and Circuits.
Show others and affiliations
2015 (English)In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 27, no 7, 721-724 p.Article in journal, Letter (Refereed) Published
Abstract [en]

We report on the optimization of pnp-type verticalcavity surface-emitting transistor-lasers based on the fusion between an AlGaAs/GaAs heterojunction bipolar transistor and an InGaAs/GaAs VCSEL using an epitaxial regrowth process. It is shown how a proper design of the base region can extend the transistor active range of operation well beyond lasing threshold, thereby resulting in typical transistor laser operational characteristics including mW-range output power, mA-range base threshold current, record-low power dissipation under laser operation, and continuous-wave operation up to at least 60°C. A pronounced breakdown in the collector current characteristics in the limit of high base current and/or emitter-collector voltage accompanied by a quenching of the optical output power is interpreted as being related to quantum well band-filling.

Place, publisher, year, edition, pages
IEEE Press, 2015. Vol. 27, no 7, 721-724 p.
Keyword [en]
Semiconductor lasers, surface emitting lasers, transistor lasers
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Physics
Identifiers
URN: urn:nbn:se:kth:diva-161188DOI: 10.1109/LPT.2015.2390298ISI: 000350877700010Scopus ID: 2-s2.0-84924873281OAI: oai:DiVA.org:kth-161188DiVA: diva2:793935
Funder
Swedish Research Council, 2010-4386
Note

QC 20150312

Available from: 2015-03-09 Created: 2015-03-09 Last updated: 2017-12-04Bibliographically approved
In thesis
1. GaAs based Vertical-Cavity Surface-Emitting Transistor-Lasers
Open this publication in new window or tab >>GaAs based Vertical-Cavity Surface-Emitting Transistor-Lasers
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The ever-increasing demand for broadband capacity of the global optical communication networks puts enormous requirements on the semiconductor laser used in the optical transmitter. Industrial standard bodies for optical communication project requirements of single-channel data rates as high as 100 Gbit/s around year 2020. This is a significant step with respect to today's technology which is only at the verge of introducing 25 Gbit/s emitters. The preferred light source for these applications is the vertical-cavity surface-emitting laser (VCSEL) which can offer cost- and power-efficient directly modulated operation. However, it has proven extremely difficult to push the modulation bandwidth of VCSELs beyond 30 GHz and radically new device concepts are demanded to meet the upcoming needs. One such new device paradigm consists of the transistor laser which is the fusion of a semiconductor laser and a high-speed heterojunction bipolar transistor (HBT) into a single device, with potential significant advantages in modulation bandwidth, noise properties and novel functionality by virtue of the three-terminal configuration. The present thesis deals with the design, fabrication and analysis of vertical-cavity surface-emitting transistor-lasers (T-VCSELs), a device previously not realized or investigated in great detail.

GaAs-based T-VCSELs are investigated both theoretically and experimentally. A three-dimensional model is set up with a commercial software package and used for performance predictions and analysis as well as design and optimization purposes. It is concluded that a T-VCSEL biased in the common-base configuration may have a bandwidth surpassing those of conventional diode-type VCSELs or a T-VCSEL itself in the common-emitter configuration. Fabricated T-VCSELs make use of an epitaxial regrowth design to homogeneously integrate an AlGaAs/GaAs HBT and an InGaAs/GaAs VCSEL. An intracavity contacting scheme involving all three terminals, undoped distributed Bragg reflectors and modulation doping are used to ensure a low-loss laser structure. The first generation of devices showed sub-mA range base threshold current in combination with a high output power close to 2 mW but did not fulfill the requirements for a fully operational transistor laser since the transistor went into saturation before the onset of lasing (IBsat<IBth). From numerical simulations this premature saturation was demonstrated being due to a lateral potential variation within the device and large voltage drops along the base and collector regions. As a remedy to this problem the base region was redesigned for a reduced resistance and transistor current gain, and the saturation current could thereby be extended well beyond threshold. These devices showed excellent transistor-laser characteristics with clear gain-compression at threshold, mA-range base threshold current, mW-range output power, high-temperature operation to at least 60°C, low collector-emitter offset voltage and record-low power dissipation during lasing. Furthermore, the collector-current breakdown characteristics was investigated in some detail and it is concluded that this, in contrast to previous models, presumably not is due to an intracavity photon reabsorption process but rather to a quantum-well band-filling effect.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2014. vii, 64 p.
Series
TRITA-ICT/MAP AVH, ISSN 1653-7610 ; 2014:16
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-156841 (URN)978-91-7595-363-2 (ISBN)
Public defence
2014-12-19, Sal/hall C, Electrum, KTH-ICT, Kista, 10:00 (English)
Opponent
Supervisors
Note

QC 20141203

Available from: 2014-12-03 Created: 2014-12-02 Last updated: 2015-04-13Bibliographically approved

Open Access in DiVA

fulltext(310 kB)151 downloads
File information
File name FULLTEXT01.pdfFile size 310 kBChecksum SHA-512
824240c618b10bd0430d2c3fc8979ccee2b4dac03a3f4afe175ce3b713f27980e1f3d0317e8ef2e46aad1269629e0d2feaa95123cdd4c36ede4104797dbd2a22
Type fulltextMimetype application/pdf

Other links

Publisher's full textScopusIEEEXplore

Authority records BETA

Hammar, Mattias

Search in DiVA

By author/editor
Xiang, YuReuterskiöld-Hedlund, CarlYu, XingangYang, ChenZabel, ThomasHammar, Mattias
By organisation
Integrated Devices and Circuits
In the same journal
IEEE Photonics Technology Letters
Electrical Engineering, Electronic Engineering, Information Engineering

Search outside of DiVA

GoogleGoogle Scholar
Total: 151 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 298 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf