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We numerically investigate the effects of a minute femtosecond pulse seed on continuous wave pumped supercontinuum generation when the frequency shift of the seed varies.
For metro applications, direct detection offers the advantages of low cost and low complexity. Discrete multi-tone (DMT) is a promising format due to its high spectral efficiency, flexibility and tolerance to chromatic dispersion (CD). In this work, single-side-band-DMT (SSB-DMT) and tuneable electrical dispersion compensation double side-band-DMT (TEDC-DSB-DMT) are summarized and compared.
The sensing performance in Brillouin-based distributed fiber sensors is ultimately depends on the signal-to-noise ratio (SNR) of the received signal. In order to enhance the SNR, thus improve the sensing performance, several wavelength diversity techniques have been proposed. This paper presents the current wavelength diversity techniques employed in both Brillouin optical time-domain reflectometry...
A joint timing offset (TO) and frequency offset (FO) estimation method based on Radon-Wigner transform (RWT) is first proposed for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) systems. The result shows that the timing and frequency synchronization performance of the proposed method are both better than the Schmidl & Cox method and fractional Fourier transform (FrFT) algorithm...
In this paper, the OSNR expressions for the cascaded system in the practical optical network is derived from the definition of OSNR. Then we analyse the OSNR changes in optical channels resulted from the variation of network topology, which is verified by optical network simulation software at the end of the paper.
We propose an accurate laser linewidth estimation technique based on the decision-aided maximum likelihood carrier phase estimator (DA-ML). Its performance is verified in M-ary quadrature amplitude modulation (MQAM) within a wide range of the laser linewidths and SNR values.
In this paper, the haze attenuation of laser affects the performance of free space optical communication (FSOC). The Haze is regarded as coated particles, which considers haze as the inner and droplet aerosol as the outer core. Based on the coated scattering theory of Christian Mätzler, the scattering model of haze aerosols is established. According to the Meteorological Bureau, the fitting relationship...
High spectrum efficiency and flexibility are the advantages of elastic optical network, which is the future direction of optical network development. Routing and resource allocation is one of the core technologies of flexible optical networks. This paper propose an improved RSA algorithm in the elastic optical network which based on OSNR impairment model. It considers both QoT (quality of transmission)...
The cognitive radio (CR) have been proposed to improve spectral efficiency and to meet growing demands for higher data rates in mobile communications and satellite communications. In this paper, we propose a blind estimation algorithm for a secondary user to estimate transmission parameters of the primary signal in an OFDM overlay system, using only the available fast Fourier transform (FFT) component...
A constant modulus algorithm-(CMA) based carrier frequency offset estimation method for coherent optical orthogonal frequency division multiplexing (CO-OFDM) system is proposed. Theoretical analysis and simulation results indicate that the frequency offset estimation range of the proposed algorithm can achieve [−5.9, +5.9] GHz, and the mean normalized estimation error can be kept under 0.001 even...
A PolDemux method using Extended Kalman Filter is proposed, which is general and independent on channel RSOP models for RSOP tracing, and shows great RSOP tracing speed, moderate PMD tolerances, fast convergence and lower complexity.
This letter puts forward weak FBGs Fabry-Perot (FP) structures with copper coating for quasi-distributed temperature measurement. The weak FBGs (−33dB) are fabricated by on-line draw tower. The sensors system exhibits the superiorities of high signal to noise ratio (SNR). At the same time, wavelength/frequency/time multiplexing immensely increases the capacity of the sensing system. In the experiment,...
A phase-sensitive optical time domain reflectometry sensing system based on Ultra-weak FBG Array using double pulses is proposed. The principle of this sensing system is elaborated. A series of simulations are carried out to optimize the parameters to increase the sensing distance of this system. The parameters contain reflectivity of UWFBG, the interval between adjacent UWFBGs and pulse width. The...
Analytical model is proposed to estimate EVM under the case of nonlinear noise for coherent optical fiber communications with digital receivers. Theoretical formula is obtained, which is validated by numerical simulations.
In this paper, an enhanced differential carrier phase extraction method for carrier-suppressed wideband signal in CEI measurement is proposed. Based on Costas loop, after orthogonal transformation, low-pass filtering and phase detection, the differential carrier phase of the received signal of the two measuring stations can be obtained directly. It is more efficient comparing with the traditional...
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