Dynamical and noise properties of laser diodes subject to strong optical feedback

Abstract

Dynamical and noise properties of laser diodes subject to strong optical feedback have been investigated. Under strong optical feedback a conventional rate-equation approach is not valid, and thus an iterative traveling-wave model has been developed to describe this operating regime. Attention has been given to identifying the transition from stable strong-feedback operation to the coherence collapse regime obtained with moderate optical feedback.

An improved analysis of semiconductor laser dynamics under strong optical feedback

“…The phase in the function is obviously given by (30) where is an integer. Equation (27) is applicable for an arbitrary amount of OFB. The so-called Lang and Kobayashi model [15] is obtained from (27) by supposing weak OFB with and a constant phase due to the round trip of time delay , such that we get for…”

“…When more than 20, the laser shows CW operation and pulsing operation with again. In such calculations, the round trips between the front facet and external mirror were limited to a single round trip , which is effective for the case of small reflectivity at the front facet (e.g., AR-coated facet) [26], [27]. Nevertheless, we compare the results in Fig.…”

“…Moreover, numerical analysis of the time-delayed rate equations of lasers is required. Rong-Qing and Shang-Ping [26] and Langley et al [27] reported improved models to analyze laser operation under strong OFB. Although the treatment in [26] is effective for the strong OFB range, the field amplitude and phase were approximated as random variables in stationary stochastic processes, which is valid if the laser dynamics are stabilized.…”

“…Moreover, application of such a model was limited to stationary analysis of operation under OFB, which is not enough to trace the phenomena in a trustworthy fashion. Although Langley et al [27] improved the Lang and Kobayashi model [15] by counting multiple reflections between the laser front facet and external mirrors, their model is still not applicable for the case of strong OFB. Moreover, the analysis in [27] was concerned only with the regime of transitions from moderate OFB-induced coherence collapse to continuous wave (CW) operation under stronger OFB.…”

Enhanced intensity fluctuations in a laser diode subject to optical feedback

“…Optical feedback also influences the noise properties of semiconductor lasers, [8][9][10][11][12][13][14][15][16][17][18]. Petermann [15] has both theoretically and experimentally demonstrated that the relative intensity noise (RIN) increases rapidly in regime IV.…”