Enhanced stability of MFA-MOPA semiconductor lasers using a nonlinear, trumpet shaped flare.

P.M.W. Skovgaard, J.G. McInerney, J.V. Moloney, R.A. Indik and C.Z. Ning

Abstract:

Monolithically integrated Flared Amplifier Master Oscillator Power Amplifier (MFA-MOPA) are studied theoretically using a high resolution computational model which resolves time as well as longitudinal and transverse space dependences and includes Lorentzian gain and dispersion dynamics. The simulations show that, by altering the linear flare of the power amplifier into a nonlinear, trumpet-shaped flare to overlap the gain region to the expanding field, the instability threshold of the MOPA is increased by 2 for single-longitudinal, single-transverse mode operation and 3 for single-transverse mode operation. This enables the MOPA to maintain a stable, near-diffraction limited output beam for higher currents before the onset of transverse instabilities. Thus the trumpet-flared amplifier enables the MOPA to emit an output beam of significantly higher power and brightness. This increased stability is due to a significantly smaller feed-back from the output facet of the trumpet shaped MFA-MOPA.

Keywords MOPA, High power semiconductor lasers, high brightness, diffraction-limited, flared amplifier, tapered amplifier, trumpet flare.

• Introduction
• Description of the model
• Numerical simulations
• Conclusion
• Acknowledgement
• References
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