Sökning: "BRAGG GRATINGS"

Visar resultat 6 - 10 av 32 avhandlingar innehållade orden BRAGG GRATINGS.

1. 6. Properties of Volume Bragg Gratings and Nonlinear Crystals for Laser Engineering

   Författare :Staffan Tjörnhammar; Fredrik Laurell; Valdas Pasiskevicius; Takunori Taira; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; volume Bragg grating; VBG; thermal effects; nonlinear optics; KTiOPO4; quasi-phase matching; photochromic damage; grey-tracking; color centers; blue-light induced infrared absorption; BLIIRA; Physics; Fysik;

   Sammanfattning : This thesis focuses on two topics: thermal limitations of volume Bragg gratings (VBGs) employed as laser-cavity mirrors and formation of color centers in KTiOPO4 and its isomorphs.To explore the mechanisms of the thermal limitations of VBGs in high power lasers, I designed and constructed a diode-pumped, solid‑state laser with a VBG as cavity mirror that had a significantly higher absorption than what is typical. LÄS MER

3. 7. On diode-pumped solid-state lasers

   Författare :Jonas Hellström; Fredrik Laurell; Valdas Pasiskevicius; Klaus Petermann; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; near-infrared lasers; end-pumped lasers; Q-switching; erbium; ytterbium; GdCOB; KGW; KYW; Co:MALO; laser materials; thermal lensing; end-pumping; spectroscopy; conical refraction; volume Bragg gratings; holographic gratings; laser tuning; Physics; Fysik;

   Sammanfattning : The research that is presented in this thesis can be divided into two major parts. The first part concerns longitudinally pumped, bulk Er-Yb lasers. In these lasers, the main limitation is the thermal shortcomings of the phosphate glass host material. LÄS MER

4. 8. Tandem optical parametric oscillators using volume Bragg grating spectral control

   Författare :Markus Henriksson; Fredrik Laurell; Hiromasa Ito; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; optical parametric oscillators; mid-infrared; volume Bragg gratings; PPKTP; ZGP; nonlinear optics; narrowband OPO; Physics; Fysik;

   Sammanfattning : This thesis describes research on near degenerate quasi phase-matched opticalparametric oscillators (OPO) where volume Bragg gratings (VBG) are used toproduce narrow oscillation bandwidth. These OPOs are then used to pump a secondOPO to generate mid-infrared radiation. The atmospheric transmission windows in the 3. LÄS MER

5. 9. Technology for photonic components in silica/silicon material structure

   Författare :Lech Wosinski; KTH; []
   Nyckelord :silica-on-silicon technology; PECVD; plasma deposition; photonic integrated circuits; planar waveguide devices; UV Bragg gratings; photosensitivity; arrayed waveguide gratings; multimode interference couplers; add-drop multiplexers;

   Sammanfattning : The main objectives of this thesis were to develop a lowtemperature PECVD process suitable for optoelectronicintegration, and to optimize silica glass composition forUV-induced modifications of a refractive index in PECVDfabricated planar devices. The most important achievement isthe successful development of a low temperature silicadeposition, which for the first time makes it is possible tofabricate good quality low loss integrated components whilekeeping the temperature below 250oC during the entirefabrication process. LÄS MER

7. 10. Fabrication and Charaterisation of Photonic Integrated Circuits

   Författare :Harendra Fernando; KTH; []
   Nyckelord :Plasma Enhanced Chemical Vapour Deposition PECVD ; Reactive Ion Etching RIE ; Photosensitivity; Bragg-gratings; Optical Add-drop De Multiplexsers;

   Sammanfattning : The past few decades have seen an explosive increase ininformation transfer, fuelled by the enormous growth of theInternet, telecommunication applications, and mass mediasystems in general. Because of the very high bandwidthpotential promised by optical fibre communication technology,the area of all-optical networking has received a great amountof attention. LÄS MER