ترغب بنشر مسار تعليمي؟ اضغط هنا

Phase coherence and extreme self phase modulation

152   0   0.0 ( 0 )
 نشر من قبل Paul Kinsler
 تاريخ النشر 2011
  مجال البحث فيزياء
والبحث باللغة English
 تأليف P. Kinsler




اسأل ChatGPT حول البحث

I study how pulse to pulse phase coherence in a pulse train can survive super-broadening by extreme self phase modulation (SPM). Such pulse trains have been used in phase self-stabilizing schemes as an alternative to using a feedback process. However, such super-broadened pulses have undergone considerable distortion, and it is far from obvious that they necessarily retain any useful phase information. I propose measures of phase coherence (i.e. supercontinuum coherence) applicable to such pulse trains, and use them to analyze numerical simulations comparable to self-stabilization experiments.



قيم البحث

اقرأ أيضاً

We present a simple approach to predict the main features of optical spectra affected by self-phase modulation (SPM), which is based on regarding the spectrum modification as an interference effect. A two-wave interference model is found sufficient t o describe the SPM-broadened spectra of initially transform-limited or up-chirped pulses, whereas a third wave should be included in the model for initially down-chirped pulses. Simple analytical formulae are derived, which accurately predict the positions of the outermost peaks of the spectra.
Extreme-ultraviolet (XUV) light is notoriously difficult to control due to its strong interaction cross-section with media. We demonstrate a method to overcome this problem by using Opto-Optical Modulation guided by a geometrical model to shape XUV l ight. A bell-shaped infrared light pulse is shown to imprint a trace of its intensity profile onto the XUV light in the far-field, such that a change in the intensity profile of the infrared pulse leads to a change in the shape of the far-field XUV light. The geometrical model assists the user in predicting the effect of a specific intensity profile of the infrared pulse, thus enabling a deterministic process.
In this paper we report phase modulation obtained by inducing a capacitive charge on graphene layers embedded in the core of a waveguide. There is a biasing regime in which graphene absorption is negligible but large index variations can be achieved with a voltage-length product as small as $V_pi,L_pi simeq 0.04 $,V,cm . Examples of phase induced changes are computed for straight waveguides and for microring resonators showing the possibility to implement several optoelectronic functionalities as modulators, tunable filters, and switches.
A phenomenological model for spectral broadening of incoherent light in silica fibers via self-phase modulation and dispersion is presented, aiming at providing a qualitative and readily accessible description of incoherent light spectral broadening. In this model, the incoherent light is approximated by a cosine power-modulated light with modulation parameters depending on the coherent time and the dispersion in fibers. A simple and practical method for spectral broadening predictions is given and demonstrated by both the straightforward NLSE-based numerical modeling and series of experiments including narrowband and broadband incoherent light in passive fibers and fiber amplifiers.
We experimentally demonstrate a negative Kerr nonlinearity for quasi-undoped graphene. Hereto, we introduce the method of chirped-pulse-pumped self-phase modulation and apply it to graphene-covered silicon waveguides at telecom wavelengths. The extra cted Kerr-nonlinear index for graphene equals n2,gr = -10^(-13) m^2/W. Whereas the sign of n2,gr turns out to be negative in contrast to what has been assumed so far, its magnitude is in correspondence with that observed in earlier experiments. Graphenes negative Kerr nonlinearity strongly impacts how graphene should be exploited for enhancing the nonlinear response of photonic (integrated) devices exhibiting a positive nonlinearity. It also opens up the possibility of using graphene to annihilate unwanted nonlinear effects in such devices, to develop unexplored approaches for establishing Kerr processes, and to extend the scope of the periodic poling method often used for second-order nonlinearities towards third-order Kerr processes. Because of the generic nature of the chirped-pulse-pumped self-phase modulation method, it will allow fully characterizing the Kerr nonlinearity of essentially any novel (2D) material.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا