High efficiency 1.3 mu m superluminescent diode with absorbing tapered waveguide

A new type of superluminescent diode (SLD) with a tapered waveguide in the absorbing region is proposed. This SLD structure monitors output power, as it emits monitor light from the rear facet that is about one-tenth the output power from the front one. Device parameters have been determined by beam propagation methods. A 1.3 mu m SLD fabricated by liquid phase epitaxy (LPE) with an absorbing waveguide 200 mu m long and with a 6.5 degrees tapered angle can emit output power of 13.5 mW from the front facet at a 200 mA driving current without lasing.