Negative group delay and pulse compression in superluminal pulse propagation

We systematically study the pulse advance and pulse compression in light propagation through a transparent, anomalously dispersive medium. Using an Argand diagram, we show that pulse compression is the only form of pulse distortion, while other forms of pulse distortion can be eliminated. Experimentally, we implement a dual-band electronic amplifier to measure the negative pulse group delay and compression and confirm that they are related via a quadratic form.