Can one prevent a diode laser with optical feedback from coherence-collapse operation without using optical isolators?

Summary form only given. Optical feedback is a well-known effect to take into account when analysing the behavior of a semiconductor laser in optical communication systems. Even for external reflections of less than 1% the laser can operate in the coherence-collapse regime associated with a chaotic behavior of the output power and a linewidth of thousand times the one in the absence of feedback. To prevent these and other detrimental effects expensive and nonintegrable optical isolators have to be included in the system. The physical behavior of a single mode semiconductor laser (SMSCL) in the coherence-collapse regime is studied here.