Analysis of impact of frequency response of two-segment DFB laser on conversion of a frequency-modulated signal to amplitude modulation through dispersion in an optical fibre is presented. A novel modulation scheme that produces a binary optical signal at the fibre output is used. This new scheme is based on the linear frequency modulation along with the Manchester coding. A 5 Gb/s optical transmission system is presented ; it uses the new method of FM-AM conversion supported transmission. The propagation of optical field through a fibre is described by nonlinear Schrödinger equation, which is solved numerically by the split-step Fourier method.
W pierwszej części artykułu przedstawiono analizę zjawiska konwersji modulacji częstotliwości na modulację amplitudy w standardowym światłowodzie jednomodowym, która powodowana jest przez dyspersję chromatyczną włókna optycznego. Część druga opisuje właściwości systemu transmisji danych o przepływności 5 Gbit/s wykorzystujący zjawisko konwersji.
EN
The conversion of frequency modulation to amplitude modulation due to fiber chromatic dispersion is described. A 5 Gb/s optical transmission system is presented. It uses the method of FM-AM conversion supported transmission. The computer simulation are carried out for a system with the following characteristics. The transmitted optical sygnal is modulated by an 7 augmented pRBS of length 2 - 1. The fiber dispersion is 17 ps/nm . km, the loss is 0,2 dB/km. Optical in-line amplifier is inserted at 100 km. The gain of the amplifier is chosen to compensation of the fiber loss. A first orderButterworth filter at the receiver is used. A new analysis of conversion of a frequency-modulated signal to amplitude modulation trough dispersion in an optical fiber is presented. The propagation of optical field through a fiber is described by nonlinear Schrodinger equation, which is solved numerically by the split-step Fourier method. Novel method of laser frequency modulation for Dispersion Supported Transmission gives optical binary signal at the receiver with greater values of the extinction coefficient as compared to the previous reseach at least in the range of 100 km < L < 200 km. The most important result of this investigation is that the maximum signal to noise ratio is reached at fR = 5 GHz for fiber lengths in the range 100 km < L < 200 km. The optimum value of the receiver low-pass filter bandwidth is almost independent of the fiber length. This frequency satisfies the Nyquist criterion.
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W pierwszej części artykułu przedstawiono analizę zjawiska konwersji modulacji częstotliwości na modulację amplitudy w standardowym światłowodzie jednomodowym, która powodowana jest przez dyspersję chromatyczną włókna optycznego. Część druga opisuje właściwości systemu transmisji danych o przypływności 5 Gbit/s wykorzystujący zjawisko konwersji.
EN
The conversion frequency modulated signal to amplitude modulation is described. A novel modulation scheme for dispersion supported transmission is proposed. A new analysis of conversion of a frequency-modulated signal to amplitude modulation through dispersion in an optical fiber is presented. In this article is compared results of this analysis and results numerical simulation phenomena of FM - AM conversion. The propagation of optical field through a fiber is described by nonlinear Schrodinger equation, which is solved numerically by the split-step Fourier method. The computer simulations are carried out for a system with the following characteristics. The transmitted optical sygnał is modulated by an augmented PRBS of length [formula] fiber dispersion is 17 ps/nm . km, the loss is 0,2 dB/km. Optical in-line amplifier is inserted at 100 km. The gain of the amplifier is chosen to compensation of the fiber loss. A first order Butterworth filter at the receiver is used. Binary frequency modulation of transmitter laser a linear frequency modulation along with the Manchester coding is used. It gives optical binary signal at the receiver with greater values of excition coefficient as compared to the previous research at the region of 100 km < L < 2000 km.
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