RESUMO
A Stokes vector based non-data-aided (NDA) differential group delay (DGD) estimation scheme with flexible bandwidth requirements is investigated. The scheme is demonstrated in both experiments and simulations for 40-Gb/s polarization-multiplexed coherent optical OFDM systems with up to 1000-km long haul transmission with an estimation error of less than 2.5 ps after 1000-km standard single-mode fiber transmissions.
RESUMO
We propose using low bandwidth coherent receivers for distributed optical performance monitoring. We demonstrate optical signal-to-noise ratio (OSNR) monitoring of both 20-Gb/s single-polarization and 40-Gb/s polarization-multiplexed coherent optical orthogonal frequency-division multiplexing (CO-OFDM) signals with a 0.8-GHz receiver using both data-aided (DA) and non-data-aided (NDA) approaches. The sampling rate of the performance monitor is much lower than the signal baud rate, so provides a cost-effective solution for distributed optical performance monitoring. The proposed method is demonstrated experimentally and through simulation. The results show that after calibration the OSNR monitoring error is less than 1 dB and the two approaches are not affected by fiber dispersion after 800-km transmission and 30-ps differential group delay (DGD).
Assuntos
Tecnologia de Fibra Óptica/instrumentação , Modelos Teóricos , Dispositivos Ópticos , Telecomunicações/instrumentação , Simulação por Computador , Desenho Assistido por Computador , Desenho de Equipamento , Análise de Falha de Equipamento , Luz , Espalhamento de RadiaçãoRESUMO
We propose an optical performance monitoring scheme that combines a tunable narrowband optical filter with asynchronous histograms to create density plots that represent probability maps of both optical power and frequency. Simulations are used to investigate the technique, and show that measurements at transmitters and filters can directly detect optical chirp. The effects of several optical impairments are also shown, comprising misaligned filters in the optical path, dispersion, nonlinear effects and optical signal to noise ratio. The density plots are affected differently by each of these impairments.