Optical Feedback Generated by Tapered Amplifiers Emitting at 1120 nm

Abstract

In this work the optical feedback generated by a tapered amplifier (TPA) emitting at 1120 nm is characterized at different operational conditions. The TPA is operated in a master oscillator power amplifier (MOPA) configuration, while the influence of pump current or seed power on the emitted feedback is investigated. Measurements are also performed with the TPA exposed to defined external optical feedback. For an estimation of the feedback from the TPA a simple formula is derived and the calculations are compared to the measurement results. With the experimental and theoretical results the required feedback resistance of the master oscillator seed source can be defined and the MOPA system optimized for certain applications with unwanted optical feedback.