CO2 glass ablation technology provides a very high degree of flexibility in the design of optical fiber sensors and optical probes for medical, sensing and industrial applications. In this paper, we review fabrication techniques for the design and manufacture of such devices, including diffusers, lensed fibers and cladding light strippers. We present an experimental characterization of the optical performance as well as a detailed description of the fabrication process for these devices.
The photonic crystal fibers (PCF) are considered as the future information support for the telecommunication system. In
this paper, a multicriteria method is used for the design of the PCFs with the user-defined optical proprieties. This
method combines the deductive and the inductive learning and it is introduced for the first time in the field of optical
fibers. These simulation tools will be optimized for PCF structures in order to optimize the parameters necessary for the
improvement of the communication system performances. The multicriteria decision analysis makes it possible to
evaluate the optical proprieties of PCFs by determining the effects of attenuation and distortion caused by Physics
Phenomena. This decision is done by the means of a relational model preferably. As a result, this method avoids the
recourse to distances and makes it possible to use quantitative and/or qualitative criteria. Moreover, it defeat some
difficulties encountered when data are expressed in different units. These advantages allow the new multicriteria
classification method to be employed easily to the diagnosis and to the design of photonic-crystals fibers.
We investigated the dispersion compensation by means of self phase modulation induced by the nonlinear Kerr effect in
photonic crystal fibers (PCF). Accurate calculations of both chromatic dispersion and nonlinear coefficient in small core
PCF were performed using a vector finite element method. Besides, ultrashort pulse propagation in PCF was simulated
using the generalized nonlinear Schrodinger equation. Conditions necessary for the formation of soliton during
propagation of a femtosecond pulse were investigated. To compensate the broadening caused by dispersion, we
thoroughly examined the pulse propagation in the anomalous dispersion regime at the wavelength λ=810nm. The study
showed that by carefully selecting laser and PCF parameters, the pulse broadening and frequency chirping, due to group
velocity dispersion of the PCF, can be compensated by using the Kerr nonlinearity of the medium.
Optical buffers are central elements in all-optical switched networks to avoid packet contention and loss. With actual traveling buffers, the delay time is discrete and predetermined by the length of the optical fiber delay line (FDL). Traveling buffers are bulky, since a large number of delay lines are required to handle multiple traffics. In this paper, we designed a variable optical delay line based on a re-circulating loop that is controlled by all-optical signal processing technology. We showed that a FDL based on fiber Bragg gratings (FBG) in combination with a single optical wavelength converter can realize variable delays. A simulator was developed to evaluate the performance and limitations of the proposed architecture.
Optics scholars did not only discover optical phenomena and laws governing them. Some of them also invented impressive optical systems and instruments or offered us techniques to juggle with optical signals and rays. One typical example of the impressive optical systems is the camera obscura invented by Ibn Al-Haytham. For techniques enabling us to easily handle optical rays, one can mention Young’s method to handle rays put into play by refraction. Nine centuries before him, Ibn Sahl proposed an elegant method to manipulate refraction related rays. These three examples will be handled in this paper, together with a historical overview inviting the reader to be in the context of this fascinating works.
Driven by the world's growing need for communication bandwidth, progress is constantly being reported in building newer fibers that are capable of handling the rapid increase in traffic. However, building an optical fiber link is a major investment, one that is very expensive to replace. A major impairment that restricts the achievement of higher bit rates with standard single mode fiber is chromatic dispersion. This is particularly problematic for systems operating in the 1550 nm band, where the chromatic dispersion limit decreases rapidly in inverse proportion to the square of the bit rate. For the first time, to the best of our knowledge, this document illustrates a new optical technique to post compensate optically the chromatic dispersion in fiber using temporal Talbot effect in ranges exceeding the 40G bit/s. We propose a new optical post equalization solutions based on the self imaging of Talbot effect.
In the present paper, we take a closer look at the design of long period fiber gratings (LPFG) which present several advantages compared to similar components. In fact, the LPFG has stronger wavelength stability when opposed to temperature variations and a better resistance against mechanical strength. These qualities offer them more importance in the industry. We use an electric arc to change the fiber characteristics and to create a fringe which presents a very thin section of the fiber that has a different refractive index. We use a computer based setup which allow us the control of the arc intensity and the discharge time and the gap between two neighbor fringes for the LPFG varies in the range of 400 to 700μm. A various optical fiber components designs and implementations are possible using electrical arc. In this paper we will expose the use of electrical arc and micro deformations for writing the Long Period Fiber Gratings (LPFG) on a single mode fiber. We take a closer look at the design of this component which present several advantages compared to similar components.
One of the most important vehicles for providing dynamic learning is interaction combined to animation. We designed a dynamic e-learning environment for teaching optics. In spite of the fact that the teacher and the learner do not share neither space nor time, dynamic teaching is implemented aiming at reducing passivity, engaging and motivating the learner, empowering him with responsibility for his own learning experience, allowing collaborative learning, popularizing complex aspects in optics, and enabling the learner to easily access and interact with the environment content at his own pace, in his own time and from wherever he might be. Audio-visual tools are used for real-time assistance. The degree of complexity is customized by supervising and interpreting the interactions of the learner so that laypeople can readily follow the course. The course is adapted to people with a modest background in physics such as clinicians, optometrists and ophthalmologists. However, the learning environment is useful for advanced topics in optics as well as for research.
Index — E-learning, dynamic teaching, interaction, optics.
A simple and handy technique to produce optical fiber components such as Bragg gratings has been used. A CO2 laser beam, focused on a single mode fiber, can change its optical properties locally, allowing therefore the creation of a Bragg grating inside the fiber itself. In the present study we investigate the effect of this laser beam on the fiber and show how optical fiber components can be produced. When exposing a single-mode optical fiber to a high-power CO2 laser beam a small device is developed insdie this fiber. Inside this micro-structure, the optical power is exchanged between the core and the cladding modes. This device may exhibit either a very selective rejection behavior similar to Bragg grating or an oscillating behavior like tapered fiber. The coupled mode theory combined with a mathmatical algorithm can be used to study the propagation of the modes involved in the fiber.
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