Double-pass amplification of picosecond pulses with a tapered quantum-dot semiconductor amplifier

Double-pass amplification using tapered semiconductor optical amplifiers (SOA) enables a potential improvement in gain and output power compared to standard single-pass configurations, particularly at low input optical power. The potential of double-pass amplification has already been demonstrated in the case of a CW input1, as well of nanosecond pulses2. To the best of our knowledge, here we report the first demonstration of double-pass amplification of picosecond pulses. A single-pass approach was also implemented, using the same tapered SOA. A comparison is drawn, demonstrating the performance enhancement achieved with double-pass amplification, which paves the way for a more (electrically-)efficient amplification of ultrashort optical pulses.