Introduction to BiDi SFP

SFP, a compact and hot-pluggable transceiver, is popular in telecommunication and data communication. As we know, most SFP transceivers utilize two fibers to achieve the data transmission. Nowadays, more and more people realize that the cost of fiber counts accounts for a large proportion, so it is necessary to find a cost-effective solution in the communication field. As an optimized version of SFP transceiver, BiDi SFP may be a good option. The following passage will focus on the overview, connection method and application of BiDi SFP.

Overview of BiDi SFP

BiDi SFP is a compact transceiver module which utilizes WDM (Wavelength Division Multiplexing) technology. The technology is increasingly popular among telecommunication and service operators because it can mix and transmit multiple wavelengths simultaneously over same unique fiber strand. With the use of this technology, BiDi SFP is specially designed for the high performance integrated duplex data link over a single optical fiber. BiDi SFP is compliant with the SFP multi-source agreement (MSA), and it interfaces a network device motherboard (for a switch, router, media converter or similar device) to a fiber optic or copper networking cable. Here is a figure of BiDi SFP, and it can help you get a general understanding of BiDi SFP’s connection method before we move on.

Structure of BiDi SFP Transceiver

Connection Method

BiDi SFP uses only one port fitted with an integral WDM coupler, also known as diplexer. The WDM coupler can combine and separate data transmitted over a single fiber based on different wavelengths of the light. For this reason, BiDi transceivers are also referred as WDM transceivers. To work effectively, BiDi SFP must be deployed in matched pairs with the opposite wavelength together. Here is a figure to help you get intuitive understanding of this. If paired BiDi transceivers are being used to connect Device A (Upstream) and Device B (Downstream), then Transceiver A’s diplexer must have a receiving wavelength of 1550nm and a transmit wavelength of 1310nm; Transceiver B’s diplexer must have a receiving wavelength of 1310nm and a transmit wavelength of 1550nm.

BiDi SFP Connection Method

Application

At present, the BiDi SFP is usually used in FTTx deployment P2P (point to point) connection. In a FTTH deployment, optical fibers are used directly to connect the central office and the customer premises equipment. But because the use of P2P structure, the customer premises equipment has to be connected to the central office on a dedicated fiber. BiDi SFP can realize a bi-directional communication on a single fiber by using WDM. This makes the connection between central office and customer premises equipment become more simple. In addition, BiDi SFP can be also applied in WDM fast Ethernet links, metropolitan area network, and inter-system communication between servers, switches, routers, OADM, etc.

Conclusion

With the increasing demand of high density and reliability of data transmission over long distance, more and more optical communication products appear on the market. The deployment of BiDi SFP instantly doubles the bandwidth capacity of the existing optical fiber infrastructure which can be a cost-effective solution in the applications. BiDi SFP is a popular industry format jointly developed and supported by many network component vendors mainly because it saves the cost of fiber. It is certain to be the first option when choosing fiber optic transceiver applied to large data rate and long distance data transmission.

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