Sökning: "threshold current"

Visar resultat 21 - 25 av 171 avhandlingar innehållade orden threshold current.

  1. 21. Semiconductor Lasers with Gratings Defined by Electron Beam Lithography

    Författare :Torgil Kjellberg; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; lasers; field-stitching errors; single-mode stability; fiber-optic communication;

    Sammanfattning : This thesis deals with the fabrication and characterization of semiconductor lasers with gratings defined by electron-beam lithography (EBL). Both distributed-feedback (DFB) lasers for fiber-optic communication and grating-surface-emitting (GSE) lasers suitable for a number of novel applications, from free-space communication to optical processing, are treated. LÄS MER

  3. 22. Optical Guiding and Feedback Structures in GaN-Based Vertical-Cavity Surface-Emitting Lasers

    Författare :Seyed Ehsan Hashemi; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : The Vertical-Cavity Surface-Emitting Laser (VCSEL) made from GaAs-based materials is an established infrared light source, and is produced in large volumes for short-distance optical links, computer mice, and thermal processing systems. A wide range of applications, such as high-resolution printing, general lighting, and biomedical diagnosis and treatment could benefit from using a VCSEL with blue or ultraviolet emission. LÄS MER

  4. 23. Design and characterization of 64K pixels chips working in single photon processing mode

    Författare :Xavier Llopart Cudié; Christer Fröjdh; Michael Campbell; Mittuniversitetet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electronics; Elektronik;

    Sammanfattning : Progress in CMOS technology and in fine pitch bump bonding has made possible the development of high granularity single photon counting detectors for X-ray imaging. This thesis studies the design and characterization of three pulse processing chips with 65536 square pixels of 55 μm x 55 μm designed in a commercial 0. LÄS MER

  5. 24. GaAs based Vertical-Cavity Surface-Emitting Transistor-Lasers

    Författare :Yu Xiang; Mattias Hammar; Guihem Almuneau; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : 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. LÄS MER

  7. 25. Structural studies of InGaAsP/InP-based lasers : By Thomas Kallstenius

    Författare :Thomas Kallstenius; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; Materialvetenskap; Materials science; Teknisk materialvetenskap; materialvetenskap; Materials Science;

    Sammanfattning : Reliable buried-heterostructure (BH) InGaAsP/InP-based laser diodes (LDs) is essentialto the operation of fiber optics communication systems. In this thesis, the structural,electrical and optical properties of such LDs have been studied. The aim has been toidentify materials-related mechanisms causing gradual emission degradation. LÄS MER