Polarization multiplexing band interpolation based OFDMA-PON (orthogonal frequency division multiple access-passive optical network) system

Abstract

The invention discloses a polarization multiplexing band interpolation based OFDMA-PON (orthogonal frequency division multiple access-passive optical network) system which is characterized in that: two paths of OFDM (orthogonal frequency division multiplexing) signals are respectively produced at an optical line terminal, and sub-bands of the two paths of OFDM signals are mutually interleaved; and through respectively carrying out optical modulation and polarization control on the OFDM signals, two paths of optical OFDM signals in the x and y polarization directions are respectively obtained, and then combined into one path so as to form optical OFDM signals without protection bands, in such a way, the bandwidth of the system is fully used. An optical distribution network divides the received optical OFDM signals into optical OFDM signals in the x and y polarization directions, then an optical beam splitter divides the OFDM signals into multiple paths, and an optical filter extracts the optical OFDM signals divided by the optical beam splitter, selects required different sub-band optical OFDM signals or different numbers of sub-band optical OFDM signals, and sends the selected signals to respective optical network units, thereby achieving the variable-speed access of the optical network units.

Description

technical field [0001] The invention belongs to the technical field of optical communication, and more specifically relates to an OFDMA-PON system based on polarization multiplexing frequency band interleaving. Background technique [0002] In recent years, with the diversification of users' business needs and the rapid development of Internet technology, the future broadband access network has put forward higher requirements for the spectrum utilization and data transmission of the system. As a modulation method with high spectrum efficiency, Orthogonal Frequency Division Multiplexing (OFDM for short) technology is one of the most promising solutions. The idea of ​​OFDM technology was proposed in the 1960s, but it was not used in optical communication systems until 2005. It is a special frequency multiplexing technology that utilizes multi-carrier modulation. The essential idea is: First, the channel is divided into several orthogonal sub-channels, the input high-speed ser...

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Problems solved by technology

[0012] In 2008, W.Shieh et al. of the University of Melbourne proposed a scheme to realize 107Gb / s coherent optical OFDM transmission using Orthogonal Band Multiplexing (OBM), the purpose of which is to overcome digital-to-analog conversion (DAC) / analog-to-digital Electrical Bandwidth Bottleneck of Conversion (ADC) Devices

On the other hand, because OFDM uses a cyclic prefix to occupy a part of the bandwidth at the edge of the subcarrier, it needs to be oversampled. According to the Nyquist sampling theorem, the sampling rate is at least twice the maximum subcarrier frequency. High sampling rate ADC / DAC It is very difficult and expensive to implement

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