High performance quantum well intermixed superluminescent diodes

Abstract

A broad spectral width superluminescent diode emitting at 1500 nm has been fabricated using post-growth quantum well intermixing. The one-step impurity induced quantum well intermixing technique incorporating ion implantation through a graded-thickness implant mask pattern is utilized here. By thermally diffusing the vacancies through the structure to the QW region, we can obtain a differential bandgap energy shift across the wafer by an amount directly related to the implant mask thickness. We use this effect to broaden the spectral width of the superluminescent diode. Output powers exceeding 1.5 mW and spectral modulation better than 0.2 dB have been achieved. The superluminescent diode is able to operate up to 85 °C showing good uncooled operation. The true inherent superluminescent mode operation of the superluminescent diode with full-width half maximum of spectrum increasing along with the increment of the current injection is also discussed. Accelerated ageing at continuous constant current has been carried out at 70 °C, 85 °C and 100 °C. The life test shows a very positive result, demonstrating that this quantum well intermixing technique is reliable for fabricating active devices.