The present invention relates to the field of optical Local Area Network (LAN), and more specifically, to Bi-Directional (Bi-Di) CWDM optical LANs.
Traditional enterprise networks have used copper connectivity such as UTP Cat. 5, 6, or 6A or coaxial for Distributed Antenna Systems (DAS). However, copper connectivity limits the network distances to 100 m and has reached the point where achieving efficient transmission at data rates beyond 10 G over 100 m of the copper cable becomes impractical.
Since the last decade, enterprise networks have been experiencing an accelerated migration from wired to wireless connections. It is expected that before 2025, more than 95% of enterprise traffic will be carried by wireless access. Newer wireless access points (WAP) require more extended and high-bandwidth channels. For example, WiFi6 can require a wired transmission of 10 G to the (WAPs). In addition, newer generation of wireless access (WiFi7) and deployment of newer cellular bands in 5 G (e.g., NR) will impose challenges to DAS using coaxial media.
Under this trend, the performance of the copper-based cabling could limit future growth in terms of data rates or reaches. Therefore, many businesses need to upgrade their local area networks (LAN) and campus networks to remain competitive.
Optical networks can provide secure and virtually limitless bandwidth for very long distances that can cover the requirement of premises and campus networks from core to access layers. Passive Optical Networks, a Time Division Multiplexing (TDM) based fiber-optic telecommunications technology used for delivering broadband network access to end-customers, can also be utilized for enterprise LAN. Passive Optical LANs (POL) could provide significant value for some enterprises since their implementation can offer longer distances than copper channels, an efficient way to provide access to many users. Also, POL can save CAPEX and OPEX using a passive distribution layer and cables with a smaller diameter that facilitates the network installation. Nevertheless, POL has some disadvantages compared with traditional point-to-point optical LAN in terms of bandwidth, latency, and security. The limitations on bandwidth compared with conventional optical LAN are caused by: Bandwidth sharing with many users based on TDM, the slower development of POL standards relative to Ethernet, the long gap between standard release and availability in the market, and the way POL operates.
Although the provided bandwidth by POL could be enough for some users in verticals such as hospitality, school, and small libraries, some enterprise networks might find the bandwidth and latency provided by POL unacceptable.
The inventors of this application found that the advantages provided by POL, such as faster and less complex deployment using smaller cables, bi-directional transmission that further reduces the number of installed fibers by half, and the passive distribution layer, can also be achieved by Ethernet networks using the apparatus and methods described in this application. This discusses implementing bi-directional transmission over the passive CDWM optical network. Using wavelength channels, multiple applications can be implemented over the same passive physical infrastructure, such as active point to point Ethernet, POL, and DAS for cellular communication networks.
A system for implementing Bi-Di fiber optic LAN has a plurality of optical channels being transmitted over a same optical fiber by using wavelength division multiplexing and wherein at least one of the optical fiber channels have bi-directional transmission. The system also has an access network side located in at least one of a zone distribution area or zone box, access network side cabling distributed across diverse physical distances with individual cable runs; and optical Ethernet transceivers that do not require the high transmitting optical power and high receiver sensitivity typically.
POL has been proposed for enterprise networks since it can offer longer distances than copper channels, it's an efficient way to provide access to many users, and it's installation flexibility. However, POL has disadvantages in bandwidth and latency compared with traditional Ethernet optical LAN. Therefore, it is not the best option for enterprises interested in future-proof infrastructure required for the fastest wireless access points such as WiFi 7.
Optical Ethernet networks used in today's data center can provide the required bandwidth for future enterprises. However, they require either an active distribution layer or point-to-point connections to the devices. For some enterprise networks with long distances or many interconnecting devices, point-to-point interconnections can be costly to implement.
In this invention, the authors disclose methods for fiber optic Bi-Di LAN configurations utilizing CWDM. The authors also disclose apparatus that enclose various fiber optical components to be used in Bi-Di LANs.
The first embodiment is shown in
Access switches, 101, are connected to core switch ports, 100, point-to-point over CWDM. According to the figure, only the trunk cable is used as Bi-Di in this method. Two separate 16-channel CWDM modules, 110, are used on either side of the LAN, core, and access. One CWDM module is used for transmitting, and the other is used for receiving, where wavelength ports are combined together at the module interface to form duplex connector, e.g., for equipment patch cord connection at the core network side. Broadband circulators, 211, are used to combine and separate the forward and reverse traveling signals. According to availability of current ITU CWDM wavelength grid, 18 channels are possible, and each channel can run multitude of Ethernet transmission speeds, 1 G, 10 G, 25 G, and other applications such as DAS and various PON applications can run on these wavelength channels as well. The LAN configuration disclosed in
In embodiment 2, as shown in
In embodiment 3, shown in
Embodiments 1, 2 and 3 in
Embodiment 4, as shown in
The example configuration in In
Embodiment 5, shown in
Similar to embodiment 4, embodiment 5 can also be constructed using circulators or isolator/splitter combinations instead of the 1×2 CWDMs, 111. For both embodiments 4 and 5, the core side cabling is constructed as duplex. However, if the core side cabling also must be in Bi-Di mode, optical components used in access side of the network (CWDM, circulators, isolators etc.) can be used in core side as well, by using the methods in the disclosure.