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A novel design of a polarization filter based on photonic crystal fiber (PCF) is proposed in this paper. With the introduction of a gold-coated air hole, the resonance strength is much stronger in y-polarized direction than in x-polarized direction at some particular wavelengths, which is due to the metal surface plasmon effects. At the wavelength of 1.31 μm, the loss of y-polarized mode is 2138.34 dB/cm while the loss is very low in x polarization. Furthermore, the loss peak can be flexibly adjusted from the wavelength of 1.26 to 1.56 μm by changing the thickness of a gold layer, and the loss in y polarization can be kept above 1200 dB/cm. The significant loss in y polarization makes this PCF a good candidate for developing a polarization filter with high performance. [ABSTRACT FROM AUTHOR]

The results of international comparisons in the field of fiber-optic communication and information transmission systems, in particular, for the average power of optical radiation (COOMET PR-S6 and APMP PR-S2 projects) and chromatic dispersion in an optical fiber (EURAMET PR-S3 project), are considered. Data on comparisons as regards the length of the optical fiber (APMP PR-S8), polarization mode dispersion (COOMET PR-S9 project), and wavelength for fiber optics (COOMET PR-S8 project), all of which are now being performed, are presented. [ABSTRACT FROM AUTHOR]

We studied the reflection spectra of one-dimensional deformed periodic photonic crystal at the optical telecommunication frequency range, using the theoretical model based on the transfer matrix method. A broad reflection bands covering the 1.3 and 1.55 $$\upmu$$ m wavelength of telecommunication was obtained. The propagation of signals is forbidden for all incident angles and for both transverse electric and transverse magnetic polarizations. The deformation of the stack was introduced according to a power law with a coefficient k that represents the deformation degree. [ABSTRACT FROM AUTHOR]

An optimal gain-flattened lumped Raman fiber amplifier (L-RFA), which was designed by cascading different chalcogenide fiber, was proposed and numerically demonstrated. The As-S fiber and the As-Se fiber were pumped by laser with different wavelengths. By solving the equation of the L-RFA, the characteristics including the gain and gain flatness of L-RFA are investigated. The results show that the L-RFA pumped by dual wavelengths can provide gain-flattened band from 1544 to 1558.4 nm with 0.0293 km fiber. Moreover, the average gain and gain flatness are 26.083 and 0.173 dB, respectively. The factors which influenced the output characteristics of L-RFA were also analyzed. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate a random fiber laser operating at 1,115 nm using a LD-pumped Yb-doped fiber laser as the pump source. We achieve about 270 mW lasing output in a 50 km standard communication optical fiber with slope efficiency more than 28 %. A new wavelength is provided for the application of random distributed feedback fiber lasers as light sources. [ABSTRACT FROM AUTHOR]

We propose a simple and efficient approach to the design of 3-wavelength backward-pumped Raman amplifiers with increased gain flatness over a wide spectral band. Three different methods dealing with the optimization of one or two different simple parameters are studied. Various examples are provided for illustration, and the dependence of both amplifier gain and gain flatness with pump power is shown. Gain flatness in the spectral range of 1,520–1,595 nm of about 1 dB for a 7.5 dB gain and of 1.8 dB for a 13.5 dB gain is demonstrated using only three pumps with wavelengths within the 1,420–1,480 nm interval. [ABSTRACT FROM AUTHOR]

A new method of data transmission in DWDM systems along existing long-distance fiber-optic communication lines is proposed. The existing method, e.g., uses 32 wavelengths in the NRZ code with an average power of 16 conventional units (16 units and 16 zeros on the average) and transmission of 32 bits/cycle. In the new method, one of 124 wavelengths with a duration of one cycle each (at any time instant, no more than 16 obligatory different wavelengths) and capacity of 4 bits with an average power of 15 conventional units and rate of 64 bits/cycle is transmitted at every instant of a 1/16 cycle. The cross modulation and double Rayleigh scattering are significantly decreased owing to uniform distribution of power over time at different wavelengths. The time redundancy (forward error correction (FEC)) is about 7% and allows one to achieve a coding enhancement of about 6 dB by detecting and removing deletions and errors simultaneously. [ABSTRACT FROM AUTHOR]

We study the interaction properties of optical soliton pulses propagating in a two-channel wavelength-division multiplexed strongly dispersion managed communication system. We analyze the effects of third order dispersion, Raman scattering and self-steepening using an ordinary differential equations model obtained by a variational method applied to the Generalized Nonlinear Schrödinger Equation. The validity of the model is assessed against the integration of the full nonlinear partial differential equations. The variational equations are initially solved for a single pulse in order to identify the launching parameters for each pulse in the first DM cell of the system. One pulse per wavelength is then injected in the transmission link. We then systematically study the evolution of multiplexed soliton trains and analyse the transmission system in terms of residual frequency shifts and interchannel interactions as the map strength is varied, focusing on the ratio of dissimilar peak powers in a broad range of dispersion difference values, concluding that the transmission characteristics improve by using specific values of unequal energies and considering higher-order correction terms. The work presented is an extension of previous analysis where isolated intra-channel two-pulse interactions had been addressed considering pulses with dissimilar energies. [ABSTRACT FROM AUTHOR]