Aculight has demonstrated spectral beam combining of four diode laser bars in a single optical cavity; each 1 cm wide diode bar included 200 individual single mode laser emitters. The beam combining was accomplished in the plane of the diode bar -- slow direction. In earlier work, Aculight has reported near diffraction limited performance from single diode laser bars where we have spectrally beam combined 200 laser emitters while maintaining a beam quality near the diffraction limit. Without spectral beam combination these diode laser bars will have a beam quality, in the plane of the bar, corresponding to an M2 of 1000. In current work, Aculight is extending this technology to demonstrate a spectrally beam combined, diode laser system of 50 Watts, with near diffraction limited beam quality. To accommodate multiple diode laser bars, optical modeling was used to design and complete sensitivity analysis of a unique optical cavity based on the Schmidt telescope principal to remove off-axis aberrations. Error trees have been developed for beam quality and efficiency that illustrates just how the efficiency and beam quality have been maintained within this system.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.