Experimental method of transfer function linewidth determination for laser amplifiers using FM-to-AM conversion.

We propose an experimental method for the determination of the transfer function linewidth of a laser amplifier. This technique is based on a transfer function scan using frequency modulation to amplitude modulation (FM-to-AM) temporal modulation measurement as a function of wavelength. Using this method, we show that the output spectrum of a laser amplifier in Q-switch mode is not representative of the transfer function of the amplifier.