All-optical synchronization of self-pulsating laser diodes

Abstract

We examine the behavior of self-pulsating laser diodes when injected with periodic optical signals. We experimentally and theoretically investigate the phase difference between the injected optical signal and the synchronized self-pulsating laser diode emission. We explore the phase difference dependence on detuning between the laser free-running self-pulsation frequency and the applied signal frequency, and on the injected signal power. The determined sensitive dependence of the phase difference on these factors has important consequences when self-pulsating lasers are used as optical signal processing elements in all-optical communication networks, where such sensitivity may lead to timing problems. © 1996 American Institute of Physics. ͓S0003-6951͑96͒02625-3͔The physics of nonlinear oscillators interacting with applied signals is a problem that has long been of intense interest.1-4 Laser diodes are particularly appropriate for investigating such phenomena as they are a relatively well understood model system for studying nonlinear dynamics and there is fundamental interest in understanding active nonlinear optical system behavior when perturbed by incident optical signals.5 A less esoteric, but nonetheless urgent, applied interest in these matters is driven by telecommunications as the increasing sophistication of high bandwidth fiber optic networks will ultimately demand high speed optically transparent systems. While existing networks are not yet alloptical and contain electronic elements that carry out specific functions such as routing and switching, it is becoming increasingly apparent that such electro-optical conversions will place severe limitations on the bandwidth of future networks. All-optical networks hold the key to communications that will be high-speed, high-volume, and more widespread than ever before, especially given the market driven constraints of effective utilization of the installed infrastructural base. Given these demands and constraints, all-optical alternatives are being sought to many functions currently performed by electronic devices in communication networks. Selection and development of these all-optical networks requires understanding of the interaction of light with active optical media; for example, in wavelength division multiplexing using semiconductor optical amplifiers 6 and in signal processing using self-pulsating laser diodes ͑SP LDs͒.7 In this letter, we examine the behavior of self-pulsating compact disk ͑CD͒ laser diodes when synchronized to externally injected optical signals. We examine the mechanism by which optical synchronization occurs and show how our numerical and experimental results can be explained on the basis of this mechanism. Calculations are found to be in excellent agreement with experimental results.SP LDs using complex, multisection devices have been shown to carry out function such as all-optical synchronization and clock extraction at high speeds. 7,8 However, future low cost networks may require simpler structures with which to implement such...

All-optical synchronization of self-pulsating laser diodes with frequency multiplication and division

“…It has previously been shown that there exists a power dependence of the phase difference between the injected optical signal and the laser output in a synchronized C D laser in the case of 1:l synchronization [19]. In this paper we find that, for frequency division, the sensitivity to the input power is even greater.…”

“…Full details of the experimental techniques have been given in [19]. A C D laser (slave laser) was synchronized to the optical output from an electrically synchronized C D laser (master laser) [19].…”

“…we present some results for 1:l synchronization[19].Figure 6 ( a )shows the numerically calculated frequency dependence of the phase difference between the Downloaded by [University of Tennessee, Knoxville] at 21:Calculated phase difference A& between injected optical signal and laser output against free-running SP frequency for three injected power levels: (a) 1:l synchronization; (b) 2 : 1 frequency division; (c) 3 : 1 frequency division. The labels indicate the injected power level and are relative to the largest power level, that is, OdB.…”

A theoretical analysis of optical clock extraction using a self-pulsating laser diode

“…We have previously used this kind of calculation to successfully predict the behavior of the optical synchronization of a CD self-pulsating laser diode [5].…”

Stabilizing periodic orbits in a chaotic semiconductor laser

“…The non-linear response of self-pulsating laser diodes to externally injected optical signals has been used to investigate their synchronization properties [19]. In order to study these features far from the equilibrium, we shall consider a driven diode laser model with two rate equations for the photon and carrier densities, denoted by SðsÞ and N ðsÞ, respectively, and written as [5] …”