TWDM-PON (Time Wavelength Division Multiplexing-Passive Optical Network) ONU (Optical Network Unit) implementation device and method based on cyclical optical tunable filter

Abstract

The invention discloses a TWDM-PON (Time Wavelength Division Multiplexing-Passive Optical Network) ONU (Optical Network Unit) implementation device and method based on a COTF (Cyclical Optical Tunable Filter), and relates to the field of PON access. The ONU implementation device comprises an optical coupler, a circulator, a gain medium, a BPF (Band Pass Filter) 1, an isolator, a WDM (Wavelength Division Multiplexing), a COTF, a COTF control circuit, a BPF 2, a receiver, a signal modulating circuit and a burst control circuit; the COTF is connected with the COTF control circuit; the optical coupler, the COTF, the WDM, the BPF2 and the receiver are connected in sequence to form a downlink chain jointly; the optical coupler, the circulator, the BPF1, the isolator, the WDM, and the COTF form a closed loop; the circulator is connected with the gain medium; the gain medium is further connected with the signal modulating circuit and the burst control circuit respectively to form an uplink chain jointly. By adopting the the device and the method provided by the invention, the selectable wavelength of the ONU receiving end and the changeable wavelength of the sending end can be realized; the requirement of the TWDM-PON system to the ONU is satisfied; the existing investment of an operator is protected, and the construction cost of the network is saved.

Description

technical field [0001] The present invention relates to the PON (Passive Optical Network, Passive Optical Network) access field, in particular to a TWDM-PON (Time Wavelength Division Multiplexing-Passive Optical Network, Time Wavelength Division Multiplexing-Passive Optical Network) based on a periodic optical tunable filter - Passive optical network) ONU (Optical Network Unit, optical network unit) implementation device and method. Background technique [0002] Because optical fiber communication has the advantages of transmission frequency bandwidth, large communication capacity, and high signal transmission quality, this technology has extremely wide applications in the field of communication. Optical access network FTTH (Fiber To The Home, fiber to the home) as an important part of the optical fiber communication network has broad application prospects, but with the enrichment of business content, the demand for bandwidth is getting higher and higher, 1G rate EPON (Ethe...

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Problems solved by technology

[0004] For the first single-wavelength increase rate, the key technology is to increase the single-wavelength bit rate in the downlink direction to 40Gb / s, and the bit rate in the uplink direction to 10Gb / s, but the following problems need to be solved: dispersion, if the rate is increased by 4 times, the dispersion will increase 16 times, which limits the transmission distance; the optical power budget, under the condition of increasing the bit rate by 4 times, to ensure the same SNR (Signal to Noise Ratio, signal-to-noise ratio), the optical power must be increased by 6dB, and the optical amplifier must be added; High-speed circuit technology on the ONU side, high-speed circuits will inevitably lead to higher costs

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