Amplified spontaneous emission effects in semiconductor laser amplifiers
Abstract
A quantitative method for predicting semiconductor laser amplifier performance in the presence of ASE (amplified spontaneous emission) is described. In order to increase the fraction of pump power that contributes to the amplification of the input laser field, an amplifier should operate at as high an excitation level as possible, even above its free-running oscillation threshold. An increase in ASE thus limits the maximum pump power, quenching the amplifier gain, efficiency, and coherence. ASE effects may be mitigated by increasing the input laser intensity, decreasing the amplifier facet reflectivities, or tuning the master oscillator so that it is resonant with the amplifier. The present analysis shows that minimizing the facet reflectivity is the most effective way to circumvent ASE limitations, especially for amplifiers operating with very-low-Q resonators and at very high excitation levels. A high excitation level gives the device better efficiency than is typical with traveling-wave amplifiers.
- Publication:
-
IEEE Journal of Quantum Electronics
- Pub Date:
- August 1990
- DOI:
- 10.1109/3.59683
- Bibcode:
- 1990IJQE...26.1363C
- Keywords:
-
- Laser Outputs;
- Semiconductor Lasers;
- Signal To Noise Ratios;
- Spontaneous Emission;
- Carrier Density (Solid State);
- Phased Arrays;
- Reflectance;
- Threshold Currents;
- Lasers and Masers