Coherence-collapse threshold of 1.3-μm semiconductor DFB lasers

Facet phase effects on the coherence collapse threshold of 1.55 μm AR/HR distributed feedback semiconductor lasers

“…Hence, a strong dependence of the coherence collapse threshold with FPE is theoretically predicted. Let us note that such results have already been confirmed experimentally [10]. As a conclusion due to the high reflection coating, the coherence collapse threshold is strongly linked to FPE.…”

“…Both approaches concluded on the importance of calculating the coupling strength coefficients [9]. Following [8], the coherence collapse threshold of DFB lasers having an antireflection (AR) coating on the emitted facet and a high reflection (HR) coating on the rear facet has been calculated and compared to experimental results [10]. It was both theoretically and experimentally shown in [10] that, due to the HR-facet, the feedback sensitivity as well as the coherence collapse threshold exhibit a quasi-parabolic distribution due to the facet phase dependence.…”

“…Following [8], the coherence collapse threshold of DFB lasers having an antireflection (AR) coating on the emitted facet and a high reflection (HR) coating on the rear facet has been calculated and compared to experimental results [10]. It was both theoretically and experimentally shown in [10] that, due to the HR-facet, the feedback sensitivity as well as the coherence collapse threshold exhibit a quasi-parabolic distribution due to the facet phase dependence. The large dispersion among the critical levels observed for a given set of DFB lasers leads to a wide range of behavior under external optical feedback which is detrimental to applications.…”

Analysis of Coherence-Collapse Regime of Semiconductor Lasers Under External Optical Feedback by Perturbation Method

“…For applications at 1.3 m µ , 350-m µ -long strained multi-quantum-well (MQW)-based antireflection (AR)/high reflectivity (HR) distributed feedback (DFB) lasers with a slope efficiency of 0.3 / WA and a threshold of instability of 15dB − have been shown to be suitable for 2.5 / Gb s transmission without optical isolators under the G.957 International Telecommunication Union recommendation, which specifies a threshold of 24 dB − (Grillot et al, 2003). For the 1.55 m µ band, more sophisticated MQW-based AR/AR chirped-grating DFB lasers were fabricated, with cavities (about 500 m µ in length) composed of a straight section followed by a stripe section of varying width.…”

Variation of the critical feedback level in a 1550nm quantum-dash Fabry-Perot semiconductor laser

“…Consequently, this strong degradation of the GS D Hfactor should theoretically produce a significant variation in the feedback sensitivity of the laser. The coherence collapse regime, in which the laser is subject to instabilities, is incompatible with data transmission because of induced high penalty 10 . One method to investigate the tolerance to optical feedback is to evaluate the onset of this regime through the following expression 11 :…”