Now showing items 1-11 of 11

    • Conservation of quantum efficiency in quantum well intermixing by stress engineering with dielectric bilayers 

      Arslan, Seval; Demir, Abdullah; Şahin, S.; Aydınlı, A. (Institute of Physics Publishing, 2018)
      In semiconductor lasers, quantum well intermixing (QWI) with high selectivity using dielectrics often results in lower quantum efficiency. In this paper, we report on an investigation regarding the effect of thermally ...
    • Facet cooling in high-power InGaAs/AlGaAs lasers 

      Arslan, Seval; Gündoğdu, Sinan; Demir, Abdullah; Aydınlı, A. (Institute of Electrical and Electronics Engineers Inc., 2019)
      Several factors limit the reliable output power of a semiconductor laser under CW operation, such as carrier leakage, thermal effects, and catastrophic optical mirror damage (COMD). Ever higher operating powers may be ...
    • Facet temperature reduction by separate pumped window in high power laser diodes 

      Arslan, Seval; Gündoğdu, Sinan; Demir, Abdullah; Aydınlı, A. (SPIE, 2018)
      The main optical output power limitation in high power laser diodes is the catastrophic optical mirror damage (COMD) initiated by facet heating due to optical absorption, which limits the reliable power and lifetime of a ...
    • High efficiency 1.9 Kw single diode laser bar epitaxially stacked with a tunnel junction 

      Zhao, Y.; Wang, Z.; Demir, Abdullah; Yang, G.; Ma, S.; Xu, B.; Sun, C.; Li, B.; Qiu, B. (IEEE, 2021-04-21)
      We report on the development of a 940-nm diode laser bar based on epitaxially stacked active regions by employing a tunnel junction structure. The tunnel junction and the device parameters were systematically optimized to ...
    • IFVD-based large intermixing selectivity window process for high power laser diodes 

      Arslan, Seval; Şahin, S.; Demir, Abdullah; Aydınlı, A. (SPIE, 2018)
      Catastrophic optical mirror damage (COMD) is a key issue in semiconductor lasers and it is initiated by facet heating because of optical absorption. To reduce optical absorption, the most promising method is to form ...
    • Low-loss regrowth-free long wavelength quantum cascade lasers 

      Gündoğdu, Sinan; Demir, Abdullah; Pisheh, Hadi Sedaghat; Aydınlı, Atilla (Institute of Electrical and Electronics Engineers, 2018-12-01)
      Optical power output is the most sought-after quantity in laser engineering. This is also true for quantum cascade lasers operating especially at long wavelengths. Buried heterostructure cascade lasers with epitaxial ...
    • Power saturation in standard and double-AR unfolded laser diode cavities 

      Peters, M. G.; Fily, A.; Rossin, V.; Demir, Abdullah (IEEE, 2016)
      We report modeling and experimental results that demonstrate mechanisms limiting the output power of broad area semiconductor lasers. The modeling comprises numerical simulations of the laser cavity with evolution of ...
    • Reduced facet temperature in semiconductor lasers using electrically pumped windows 

      Demir, Abdullah; Arslan, Seval; Gündoğdu, Sinan (SPIE, 2019-02)
      The self-heating of semiconductor lasers contributes directly to facet heating and consequently to the critical temperature for catastrophic optical mirror damage (COMD) but the existing facet engineering methods do not ...
    • Submicron size all-semiconductor vertical cavities with high Q 

      Demir, Abdullah; Apaydın, D.; Kurt, H. (Institute of Electrical and Electronics Engineers Inc., 2019)
      The miniaturization of lasers promises on-chip optical communications and data processing speeds that are beyond the capability of electronics and today's high-speed lasers. Lasers with low-power consumption are one of the ...
    • Thermal characterisation of quantum cascade lasers with Fabry Perot modes 

      Gündoğdu, Sinan; Pisheh, Hadi Sedaghat; Demir, Abdullah; Günoven, M.; Aydınlı, Atilla; Sirtori, C. (SPIE, 2018)
      Quantum cascade lasers are coherent light sources that rely on intrersubband transition in periodic semiconductor quantum well structures. They operate at frequencies from mid-infrared to terahertz. In cases of long ...
    • Time resolved Fabry-Perot measurements of cavity temperature in pulsed QCLs 

      Gündoğdu, Sinan; Pisheh, ‪Hadi Sedaghat; Demir, Abdullah; Günöven, M.; Aydınlı, Atilla; Sirtori, C. (OSA - The Optical Society, 2018)
      Temperature rise during operation is a central concern of semiconductor lasers and especially difficult to measure during a pulsed operation. We present a technique for in situ time-resolved temperature measurement of ...