The high power and broad spectral output of superluminescent diodes (SLDs) are desirable for fiber optic gyroscopes, optical sensors and short to medium haul communications. Certain applications are sensitive to spectral modulation on the subnanometer wavelength scale where coherent interference can be a source of noise. We present a simple SLD design which eliminates the optical feedback within the chip normally responsible for spectral modulation. Although the design can be applied to conventional SLD wavelengths, initial device demonstration at 960 nm has been chosen to illustrate SLD operation in a materials system in which spectral modulation is particularly difficult to suppress. Ridge waveguide based SLDs suitable for coupling to single mode fiber have been fabricated. Typical output is 10 mW cw at 140 mA with a spectral width of 30 nm and less than 5% spectral modulation over a wide range of operating conditions.