40G dense wavelength division general optical module market is so far the first limited to 1000 km above the core long-distance optical network. Because of its good optical signal-to-noise ratio and optical nonlinear characteristics, the differential phase shift keying (DPSK) modulation and coding format is more appropriate in this application and become the primary selection of suppliers. Several different differential phase shift keying module in order to meet the different needs of the core network has been put on the market, such as partial differential phase shift keying (P-DPSK) and free spectral range (FSR) to switch the differential phase shift keying modules (Switchable of FSR DPSK).
The primary purpose of the different modules of the transmission performance of its channel spacing of 50GHz and 100GHz with different types and number of reconfigurable optical add-drop multiplexer (ROADM) dense wavelength spectral transmission system optimization . Recently, there is a new type of continuous optimization of differential phase shift keying module (CO-DPSK) market quickly by the system integrator attaches great importance to. Compared to other differential phase shift keying module, it can provide real-time and continuous optimization of the transmission performance under a variety of optical network cascade filter conditions. So it can not only maintain excellent transmission performance, but also greatly simplifies the optical transmission system with a reconfigurable optical add-drop multiplexer network maintenance. Continuous optimization of the filter shape of the differential phase shift keying module to run in real-time optimization process does not need the equivalent of the optical network, the number of cascaded filters and the effective bandwidth of the optical transmission channel pre-understand.Moreover, it is also light on the transmission channel residual dispersion, group delay ripple and nonlinear effects of signal distortion, which sparked the operative part of compensation.
The following figure shows the CO-DPSK with a number of different other types of spectral range (FSR) DPSK module performance simulation and experimental results (Bw indicate optical channel filter based on second order Gaussian distribution pattern (SG2), the effective bandwidth ; the Exp indicate the experimental results for different FSR; the vertical axis to indicate the required optical signal-to-noise ratio) set the BER. The figure shows the effective bandwidth of a normal optical transmission channel fell from 25GHz to 65GHz within the scope of the overall CO-DPSK transmission performance than several other differential phase shift keying module has the superiority. Precisely because of this, continuous optimization module of differential phase shift keying (CO-DPSK) is considered to be a common module is especially suitable for long-distance and regional networks. Generally speaking, in these networks, the transmission quality of fiber is often good, is not simple fiber polarization mode dispersion (PMD) values too much doubt.
没有评论:
发表评论