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We use the well-known duality between paraxial diffraction in space and dispersion in time to propose a time-domain analog to spatial Fraunhofer diffraction. This analog permits the design of real-time optical Fourier-transformer systems. These systems are shown to be realizable by use of linearly chirped fiber gratings as dispersive media.
In this paper we propose analyse the apodisation or windowing of the coupling coefficients in the unit cells of coupled resonator waveguide devices (CROWs) as a means to reduce the level of secondary sidelobes in the bandpass characteristic of their transfer functions. This technique is regularly employed in the design of digital filters and has been… (More)
We show that a temporal effect that is equivalent to the spatial self-imaging (Talbot) effect applies to the reflection of periodic signals from linearly chirped fiber gratings. The effect can be used for multiplying the repetition frequency of a given periodic pulse train without distorting the individual pulse characteristics. The practical limit on the… (More)
A new type of clamp-on magneto-optical current transducer based on the Faraday effect is presented. It is openable, hybrid, and square-shaped, and it has an internal mirror that allows the current sensitivity to improve and the effects of the optical activity and temperature-dependent linear birefringence to be rejected. The design and the simulated… (More)
The letter presents a technique for Nth-order differentiation of periodic pulse train, which can simultaneously multiply the input repetition rate. This approach uses a single linearly chirped apodized fiber Bragg grating, which grating profile is designed to map the spectral response of the Nth-order differentiator, and the chirp introduces a dispersion… (More)
We propose a method to reconstruct the grating period in fiber grating structures from the field reflection coefficient or the related impulse response. The method is based on the joint time-frequency signal analysis and uses the Wigner-Ville and the spectrogram distributions. Results show good agreement between exact and reconstructed functions.
We propose and analyze a novel (to our knowledge) approach to implement the spectral self-imaging effect of optical frequency combs. The technique is based on time-domain multilevel phase-only modulation of a periodic optical pulse train. The method admits both infinite- and finite-duration periodic pulse sequences. We show that the fractional spectral… (More)
We propose a method for phase, time-delay, and impulse-response reconstruction from spectral power reflectance or reflectivity and apply it to uniform fiber Bragg gratings. This method is based on causality conditions and uses Hilbert and Wiener-Lee transforms. Results show a good agreement between exact and reconstructed functions.
We demonstrate a simple technique for the implementation of an all-optical integrator based on a uniform-period fiber Bragg grating (FBG) in reflection that is designed to present a decreasing exponential impulse response. The proposed FBG integrator is readily feasible and can perform close to ideal integration of few-picosecond and subpicosecond pulses.
A novel method of analysis of double-parallel amplified recirculating optical-delay lines (DPAROD) is presented. The location of the maxima and the minima of the transfer function for this configuration is calculated and experimentally demonstrated. The influence of different parameters, such as the coupling coefficients, gains, lengths of the fiber loops… (More)