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Enhanced Fundamental Linewidth of a Laser Due to Outcoupling

  • W. A. Hamel
  • M. P. van Exter
  • J. P. Woerdman
Chapter

Abstract

A laser can be thought of as an amplitude-stabilized oscillator. Such an oscillator has a finite linewidth, due to phase-changing events. In most cases these events have a “technical” origin, such as fluctuations in the cavity length due to acoustic perturbations. However, even in a perfectly stable environment there is still phase diffusion due to spontaneous emission; this leads to the quantum-limited or fundamental linewidth as first discussed by Schawlow and Townes [1]. In recent years it has been shown by others [2,3,4,5] and by us [6,7,8,9] that the standard (Schawlow-Townes) formula for the fundamental linewidth must be modified if the outcoupling through the mirrors is large. In this paper we review our work [6,7,8,9] in this field, starting in section 2 with theory. In section 3 we report on the diagnostics of the semiconductor lasers used in the experiments. The technique of linewidth measurement is discussed in section 4 and actual results are given in section 5, together with a comparison with theory.

Keywords

Spontaneous Emission Semiconductor Laser Phase Diffusion Laser Linewidth Spontaneous Emission Rate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Plenum Press, New York 1993

Authors and Affiliations

  • W. A. Hamel
    • 1
    • 2
  • M. P. van Exter
    • 1
  • J. P. Woerdman
    • 1
  1. 1.Huygens LaboratoryUniversity of LeidenLeidenThe Netherlands
  2. 2.PTT Telecom b.v.Gravenhagethe Netherlands

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