A broadband superluminescent III-V-on-silicon light-emitting diode (LED) was realized. To achieve the large bandwidth, quantum well intermixing and multiple die bonding of InP on a silicon photonic waveguide circuit were combined for the first time, to the best of our knowledge. The device consists of four sections with different bandgaps, centered around 1300, 1380, 1460, and 1540 nm. The fabricated LEDs were connected on-chip in a serial way, where the light generated in the smaller bandgap sections travels through the larger bandgap sections. By balancing the pump current in the four LEDs, we achieved 292 nm of 3 dB bandwidth and an on-chip power of -8 dBm.