BiDi SFP—An Economic Choice For Gigabit Ethernet Network

Almost all modern optical transceivers utilize two fibers to transmit data between switches, firewalls, servers, routers, etc. One fiber is dedicating to receiving data from networking equipment while the other fiber is dedicating to transmitting data to the networking equipment. A new optical transceiver technology is now available that allows transceivers to both transmit and receive data to/from interconnected equipment through a single optical fiber. This technology first emerged about 7 years ago and had led to the development of Bi-Directional transceivers, or BiDi transceivers for short.

The Bi-Directional Small Form Factor Pluggable (BiDi) is a compact optical transceiver module which is used in optical communication for both telecommunications and data bidirectional communications applications. It interfaces a network device mother board (for a switch, router or similar device) to a fiber optic or unshielded twisted pair networking cable. It is a popular industry format supported by several fiber optic component vendors. In the following text, the operation principle, advantages and applications of BiDi SFP transceivers will be provided.

Working Principle of Bidi SFP Transceivers:

The primary difference between BiDi transceivers and traditional traditional optical transceivers is that BiDi transceivers are fitted with Wavelength Division Multiplexing (WDM) couplers, also known as diplexers, which combine and separate data transmitted over a single fiber based on the wavelengths of the light. For this reason, BiDi transceivers are also referred to as WDM transceivers.

To work effectively, BiDi transceivers must be deployed in matched pairs, with their diplexers turned to matched the expected wavelength of the transmitter and receiver that they will be transmitting data from or to.

For example: If paired BiDi transceivers are being used to connect Device A (Upstream) and Device B (Downstream), as shown in the figure below, then:

• Transceiver A’s diplexer must have a receiving wavelength of 1490 nm and a transmit wavelength of 1310 nm.
• Transceiver B’s diplexer must have a receiving wavelength of 1310 nm and a transmit wavelength of 1490 nm.

Features and Advantages of BiDi Transceivers:

Bidi SFP transceiver module series are specifically designed for the high performance integrated duplex data link over a single optical fiber. These transceivers are compliant with the SFP Multisource Agree (MSA). With the features of hot pluggability, these modules offer an easy way to be installed into SFP MSA compliant port at any time without the interruption of the host equipment operation online. The BiDi SFP modules can support tranmission distance up to max 120 km, which is far beyond the traditional modules.

The obvious economic advantage of utilizing BiDi transceivers, such as BiDi SFP, BiDi SFP+ transceivers, is the reduction in fiber cabling infrastructure costs by reducing the number of fiber patch panel ports, the amount of tray space dedicated to fiber management, and less fiber cable counts.

While BiDi transceiver costs more than traditional transceivers, they utilize half the amount of fiber per unit of distance. For many networks, the cost savings of utilizing less fiber is not enough to offset the higher purchase price of BiDi transceivers.

Applications

BiDi SFP transceiver is applicable to many access networks: Passive Optical Networks (PON) and Point-to-Point, Digital video and Closedcircuit television (CCTV) applications, Inter-system communcation between servers, switches, routers, Optical Add Drop Multiplexer (OADM), WDM Fast Ethernet Links, SDH/STM-1, SONET/OC3, Metropolitan area networks and other optic link.

Summary

Bidi (WDM) SFP transceivers are mainly used in optical communication for both telecommunications and data bidirectional communications applications over only one stand of fiber. It is a definitely good choice for you to connect Gigabit Ethernet network.