New linewidth enhancement determination method in semiconductor lasers based on spectrum analysis above and below threshold

New linewidth enhancement determination method in semiconductor lasers based on spectrum analysis above and below threshold

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Linewidth measurements of singlemode and multimode InGaAsP lasers were made above and below threshold with adapted interferometers. Linewidth against inverse power plots, Δv = f(1/P), show different Schawlow–Townes slopes above and below threshold. Differences have been observed depending on singlemode or multimode laser behaviour. In the singlemode case the linewidth enhancement factor has been determined (α = 2.6) by extrapolating and correlating results above and below threshold.


    1. 1)
      • H. Gerhardt , H. Weling , A. Güttner . Measurements of the laser linewidth due to quantum phase and quantum amplitude noise above and below threshold. Z. Physik , 113 - 126
    2. 2)
      • Destrez, A., Juncar, P., Toffano, Z.: `Power and modal analysis of laser spectra at 1300nm', Proc. Opto 88 Conf., 1988, Paris, p. 247–250.
    3. 3)
      • W. Elsässer , E. Göbel . Multimode effects in the spectral linewidth of semiconductor lasers. IEEE J. Quantum Electron , 687 - 692
    4. 4)
      • J. Manning , R. Olshansky . Strong influence of nonlinear gain on spectral and dynamic characteristics of InGaAsP lasers. Electron. Lett. , 496 - 497
    5. 5)
      • M. Lax . Noise in self-sustained oscillators. Phys. Rev. , 290 - 307
    6. 6)
      • M. Osiński , J. Buus . Linewidth broadening factor in semiconductor lasers—an overview. IEEE J. Quantum Electron , 9 - 29
    7. 7)
      • M.-C. Amann . Linewidth enhancement in distributed-feedback semiconductor lasers. Electron. Lett. , 569 - 571
    8. 8)
      • J.S. Cohen , D. Lenstra . The critical amount of optical feedback for coherence collapse in semiconductor lasers. IEEE J. Quantum Electron. , 10 - 12

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