Demonstration of high pointing accuracy, dual-axis collimation of 49 emitter diode bar using a laser-written custom phase-plate

摘要

We present our work on a single optical component that combines fast-axis smile and lens error correction with slow-axis collimation, produced by a laser micro-machining technique. Customization of focal length of slow-axis lenses allows optimization of fill-factor of diode laser bars. We report on the use of the technique for a 49 single mode emitter array, 975 nm bar providing 30W cw output, obtaining excellent beam properties with RMS pointing error of 3% and 6% of far field divergence in fast and slow-axis, respectively. We observed a pitch mismatch of 0.03% between the slow-axis lens array and emitters, with slow-axis beam pointing clearly affected by chip thermal expansion.