High-speed operation of optical preamplifier using inverted amplified spontaneous emission signal of saturated semiconductor optical amplifier

We investigate the dynamics of an optical preamplifier using an inverted amplified spontaneous emission (ASE) signal of a saturated semiconductor optical amplifier (SOA). The small-signal response of the converted ASE was measured and its 3 dB bandwidth was over 9 GHz when the injection current of the SOA was increased to more than 200 mA. The rise and fall times of the converted output ASE were also evaluated. In addition, we achieved 10 Gbit/s operation of the proposed preamplifier. The minimum receiver sensitivity was improved by 7 dB using the preamplifier for the 10 Gbit/s signal.