Mixed passive optical network system and transmission method thereof

Abstract

The invention discloses a mixed passive optical network system and a transmission method thereof in the technical field of fiber optical communication. The mixed passive optical network system comprises an optical circuit terminal, an optical code division multiplexing coder / decoder, an optical multiplexer / de-multiplexer, feeder line optical fiber, a remote node and optical network units, wherein the output port of the optical circuit terminal is connected with the corresponding optical code division multiplexing coder / decoder, and the output of the optical code division multiplexing coder / decoder and the output of another optical code division multiplexing coder / decoder together enter the feeder line optical fiber through the optical multiplexer / de-multiplexer for transmission; after being transmitted to another optical multiplexer / de-multiplexer, optical signals are transmitted into the input port of other optical multiplexer / de-multiplexer; and after coding / decoding, the optical signals enter the remote node to be transmitted to each corresponding optical network unit. In the invention, the optical circuit terminal and the optical network unit structure of the transitional passive optical network does not need changing, the optical code division multiplexing coder / decoder has transparent signal format for the transmitted signals, and transparent capacity expansion and smooth updating of the system can be realized.

Description

technical field [0001] The present invention relates to a system in the technical field of optical fiber communication and a transmission method thereof, in particular to a hybrid passive optical network system and a transmission method thereof. Background technique [0002] The passive optical network provides the connection between the optical line terminal and multiple optical network units, and shares the optical fiber medium between the optical line terminal and the remote node. While saving costs, it can provide high-bandwidth data transmission. Access network bandwidth requirements provide a powerful solution. However, whether it is a TDM PON or a WDM PON, its limited time slot resources and wavelength resources limit the number of ONUs in the PON, so hybrid PONs should be used It is born, which provides a possibility for the system expansion of the passive optical network. A passive optical network that uses both wavelength resources and time slot resources has bee...

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Problems solved by technology

[0003] After searching the prior art documents, it was found that Ken-ichi Kitayama et al. published a paper entitled "OCDMA over WDM PON-solution to gigabit-symmetric FTTH (solve Gigabit uplink and downlink symmetry) in "Journal of Lightwave Technology (Journal of Lightwave Technology)". Fiber-to-the-home optical code division multiplexing / wavelength division multiplexing passive optical network)", this paper proposes a hybrid passive optical network structure of optical code division multiplexing / wavelength division multiplexing, in this structure The sending and receiving end of each group of signals in the system introduces an optical code division multiplexing encoder / decoder, thereby increasing the number of access users in the passive optical network, but this technology needs to be ineffective for the existing numerous wavelength division multiplexing. The optical line terminals and optical network units of the source optical network are redesigned and planned, and the upgrade cost is relatively high

[0004] After searching, it was found that Xu Wang et al published a paper entitled "field trial of 3-WDM*10-OCDMA*10.71-Gbs asynchronousWDM / DPSK-OCDMA using hybrid ED without FEC and optical thresholding (using a hybrid codec without forward error correction and optical limiter to realize 3 wavelengths*10 codewords*10.7 gigabits per second asynchronous wavelength division multiplexing / differential phase keying modulation optical code division Multiple Access Experimental System)", which proposes an improved hybrid passive optical network structure, in which the optical line terminal only uses a multi-port optical code division multiplexing encoder / decoder to realize Different encoding is performed on different signals at the same time, while increasing the number of access users, it saves the number of optical code division multiplexing encoders / decoders required, but this technology still encodes a single group of signals separately, and each optical network The unit still needs a set of optical code division multiplexing encoder / decoder, so when the system is expanded, the idea of ​​not changing the existing transceiver module of the wavelength division multiplexing passive optical network is still not realized

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