The word “soliton” is meant to describe the particle like behavior of the optical pulses propagating through a medium . The pulses envelope for soliton not only propagates undistorted but also survives collisions just as particles do. The soliton are very narrow, high intensity optical pulses that retain their shape through the interaction of balancing pulse dispersion with the nonlinear properties of an optical filter. If the relative effect of SPM and GVD are controlled just right, and appropriate pulse shape is chosen, the pulse compression resulting from SPM can exactly offset the pulse broadening effect of GVD. Depending upon the particular pulse shape chosen , the pulse either does not change its shape as it propagates, or it undergoes periodically repeating change in shape. The pulses that do not change in shape are called fundamental solitons , and those that undergo periodic shape changes are called higher-order solitons .
As discussed earlier, when a high-intensity pulses is coupled to fiber , the optical power modulates the refractive index seen by the optical excitation. This induces phase fluctuations in the propagating wave, thereby inducing a chirping effect in the pulse. When such a pulse traverses a medium with a positive GVD for the constituent frequency, the leading part of the pulse is shifted towards a longer wavelength, so that the speed in that portion increases. Conversely, in the trailing half , the frequency rises so the speed decreases. This causes the trailing edge to be further delayed. Consequently , in addition to a spectral change with distance, the energy in the center of the pulse is dispersed to either side, and the eventually take a rectangular shape.
On the other hand, when a narrow high-inten...
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...tion formats Optics Communications, Volume
259, Issue 2, 15 March 2006, Pages 640-644Hankui
Liu, Xianmin Zhang and Kangsheng Chen
13. Effect of polarization mode dispersion in optical soliton transmission in fibers Physica D: Nonlinear
Phenomena, Volume 188, Issues 3-4, 1 February
2004, Pages 241-246,Akira Hasegawa
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Communications, Volume 227, Issues 1-3, 1 November
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15. Analytical theory of pulse broadening due to polarization mode dispersion and polarization- dependent loss Optics Communications, Volume 223,
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Waves are all around us and come in various forms. Sound waves can travel through air because air is made of molecules, which carry the sound. Another type of wave is electromagnetic waves, which are different than sound waves because they don’t need molecules to travel. This means that electromagnetic waves can travel through air and solid materials as well as empty space (Groleau 2011). The electromagnetic spectrum consists of all waves of energy found in our universe. Radio waves, microwaves, infrared light, visible light, UV light, X-rays, and gamma rays, are the are the most common wavelengths on the spectrum. Wavelength is the distance between one wave crest (peak) to the next. Waves in the electromagnetic spectrum vary in size-- from very long radio waves the size of buildings, to very short gamma rays smaller than the size of the nucleus of an atom. But you may ask, are all of these waves that different from one another? The answer in fact, is no! What differentiates these types of waves is the amount of energy they carry. Photons, the smallest massless unit of energy, bundle up and travel in waves. The amount of photons that travel are measured and classified by the energy they posses. As the wavelength of the waves decrease, the amount of energy of the photons increases (Bitesize 2011).
The spectral bands with frequencies I-m are called Stokes Raman bands whereas and those of I+m are called anti-Stokes. Thus the energy differences between the incident and the Raman scattered photons are equal to the frequencies of lattice vibrations or phonons.
The filter, an amplifier with an electronic filter referred to as a bandpass filter, is set to only allow a specific range of frequencies to continue on. The filter uses rejection to block any frequencies that do not fall into this range. This is helpful in reducing a lot of noise and giving a clear signal. Harmonic imaging is where the fundamental frequencies are actually filtered out, allowing the harmonic frequencies to pass through (Kremkau, 2011). Coded excitation helps with harmonics by creating shorter and stronger pulses. Detection, or demodulation, is where the echo voltages, which are received as radio frequencies, are converted into amplitude/video form (Miele, 2006). This happens in two parts, rectification and smoothing. During rectification the pulses are cut into ½ wave sections and refigured making them appear all positive. With smoothing, the humps are smoothed out so the pulse appears in video form. Dynamic range is used to compress the intensity ratio into one that can be displayed (Kremkau, 2011). Figure 2 shows the effect of different dynamic range settings on the same image. There is a large difference between the dynamic range that the human eye is able to detect and that of the reflected signals, and for this reason, compression must be performed (Miele,
In this essay I will be elaborating on the concept of communication within the mental health services. I will further explore it’s effectiveness. The names of all involved in this reflection have been altered and pseudonym used in accordance with (NMC 2008). I will explore the definition of communication, its rationale and its application within my professional area. My reflection is based on Gibbs Reflective cycle (1988) with 6 stages: description, feelings and thoughts, evaluation, analysis, conclusion and action plan. My reflection shows my contribution in communication practice working to facilitate Joe’s recovery journey within a multidisciplinary team. My reflection is based on CPA in MDT meetings. A CPA is regularly conducted to facilitate Joe’s effective recovery journey. An integrated care pathway in this case refers to anticipated care set in a timely manner, written and agreed by the mental health multidisciplinary team. Its agreed standards includes Joe’s milestones and clinical interventions, logged on stage when its occurrence is expected, and it also acts as a basis for a payment system as highlighted by Darzi (2008). In order to work collaboratively, communication skill is essential in allowing development of trust and benefit for Joe and team members. This results in providing Joe a holistic and person centred care which entails treating his biological, psychological and social needs (Pence, 1999).
When light interacts with objects that are much smaller than the wavelength of the light, the light being scattered, rather than reflected. The electrons of such a small object are all shaken up and down at the same time by the electric field of the light wave, and they radiate that frequency of light in all directions. It turns out that the higher the frequency of the light, the more the light is scattered.
The interference of waves causes a variable electric field, at each oscillator site, both in direction and in phase, so that the oscillator interacts with an effective wave of constant direction and phase for only short (coherence) time relative to relaxation times and yet longer than the period of the EM wave:
-umulates an extra phase shift. This effect is known as SPM since light causes a phase change on itself [DH96]. SPM refers to the selinduced phase shift experienced by an optical field during its propagation in optical fibers. The intensity-dependent nonlinear phase shift [D305]
In recent years, network coding [1], [2] has been considered as an auspicious information network paradigm for augmenting the throughput of multiple unicast networks [5]. The pioneering researches of network coding were undertaken by R. Ahlswede, N. Cai, S.-Y.R. Li and R.W. Yeung. Their discovery, which was first introduced in [1][2], are considered to be the crucial breakthrough in modern information theory and the time of its appearance, is recognized as the beginning of a new theory-Network Coding theory. In these elegant, succinct articles, within the purview of rigorous mathematics, the glimmering of an optimal network protocol for multiple unicast network was introduced in which the key idea is considering digital information as wave [riis].
different paradigm – that of staccato bursts mistily but surely connected by the wispy links of
Scintillation may be the most noticeable one for FSO systems. Light traveling through scintillation will experience intensity fluctuations, even over relatively short propagation paths. The scintillation index, σi2 describes such intensity fluctuation as the normalized variance of the intensity fluctuations given by
Direct Broadcast satellite (DBS) delivers hundreds of TV channels to millions of people around the world. Satellite owners buy slots in space and lease assigned transponder frequencies to service providers. In this paper, I briefly introduce the history and development of DBS, the major vendors of the products, and overall market situation. In order to illustrate why DBS is such a popular technology, I also give out the comparison between DBS and the traditional cable TV. Both of them have advantages and disadvantages. But the competitive advantages of DBS will make it attract more subscribers thus gain larger market share in the future.
Simultaneous communication, also known as Sim-com is a form of communication process that utilizes both signs and sound. Quite often Sim-com has been referred to as a sign supported speech; these signs are usually in English in order to ensure that there is fluency in the language. In this, it is noted that some other non-verbal cues like the use of finger spelling and visual aids which rhyme to the spoken language can be used. Simultaneous communication has always been known to be a form of communication that is intended to help people who have hearing problems (deaf) understand what is being said. In this, it is realized that over the years, Sim-com has been able to utilize other systems of communication like seeing essential English. Sim-com has proven its advantageous use in both the deaf and hearing people because it presents both the spoken language and also the non-verbal. Simultaneous language is not only used by the deaf, but also used when communicating with students at the preschool level. This is important because these children tend not to understand verbal communication fully (Beginnings, 2014).
Refraction is a process that occurs when light travels between media of different optical density. Light travels at a speed of roughly 3.0 × 108ms-1 in a vacuum. A vacuum has a refractive index n=1.00. The speed at which the light is travelling will decrease as it moves into differently optically
"Properties of sine waves." University of Manitoba. University of Manitoba, 2010. Web. 29 Nov. 2013. .