Intracavity phase correction of an external Talbot cavity laser with the use of liquid crystals

Arrays of GaAlAs emitters have been diffractively coupled by using an external Talbot cavity to support a single spatial mode; however, element-to-element phase differences distort the desired spatial mode. To enable element-to-element phase correction, we incorporated a 20-element array of tunable liquid-crystal phase shifters into a 20-element GaAlAs external Talbot cavity laser. Using the tunable phase shifters, we corrected spatial mode distortions, which resulted in 663 mW of nearly diffraction-limited power.