Recovery of Laser-Diode Coherence Length by a Photorefractive Double Phase-Conjugate Mirror

Abstract

We report an experimental study of dynamic coupling of two laser diodes (LD's) with a double phase-conjugate mirror (DPCM) in a Bi₁₂TiO₂₀ fiber-like crystal. After the DPCM is recorded in the crystal, one of the LD's is switched to the multimode regime, while the other remains lasing in the single longitudinal mode. Nevertheless, the DPCM produces phase locking of the single-mode laser with one of the longitudinal modes of the multimode laser. Only the longitudinal mode survives after the transmission through the DPCM, demonstrating the coherence length recovery of the multimode laser.