Introduction to Bi-Directional SFP

Almost all modern optical transceivers utilize two fibers to transmit data between switches, firewalls, servers, routers, etc. The first fiber is dedicated to receiving data from networking equipment, and the second fiber is dedicating to transmitting data to the networking equipment. But there is a type of fiber optic transceiver module called BiDi (Bi-Directional) transceiver to break this rule. What's BiDi transceiver? How does it work? And why people believe it will have broad market prospect? This tutorial may give you the answer.

What's BiDi Transceiver?
BiDi transceiver is a type of fiber optic transceivers which is used WDM (Wavelength Division Multiplexing) Bi-directional transmission technology so that it can achieve the transmission of optical channels on a fiber propagating simultaneously in both directions. BiDi transceiver is only with one port which uses an integral bidirectional coupler to transmit and receive signals over a single fiber optical cable. Thus, it must be used in pairs.

How Does BiDi Transceiver Work?
The primary difference between BiDi transceivers and traditional two-fiber fiber optic 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 tuned to match the expected wavelength of the transmitter and receiver that they will be transmitting data from or to.

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

While BiDi transceivers (a.k.a. WDM transceivers) cost more to initially purchase than traditional two-fiber transceivers, they utilize half the amount of fiber per unit of distance. For many networks, the cost savings of utilizing less fiber is enough to more than offset the higher purchase price of BiDi transceivers.

Generic Reliability Assurance Requirements for Passive Optical Components


Passive optical components help eliminate many bottlenecks of conventional communications systems. Replacing active components with passive components provides a significant cost savings by eliminating the need to power and service active components in the
transmission loop.

GR-1221, Issue 3, presents the i-fiberone view of proposed generic reliability assurance requirements for passive optical components, and is directed toward an equipment supplier's design engineering, manufacturing, procurement, and reliability/quality organizations.
Common forms of passive fiber optic branching components include splitters, couplers, and wavelength division multiplexers (WDM-MUXES)and demultiplexers (WDM-DEMUXES).

The new issue of GR-1221 contains updated generic and reliability assurance requirements for passive optical components, and now has added value for system developers and component manufacturers.

Updates include:
Requirements for the efficient and cost-effective operation of components in various environmental conditions such as salt and fog, water immersion, and exposure to airborne contaminants Requirements for specific packaging and shipping tests Aligns with general industry specifications for system developers Aligns with critical NEBS requirements developed since the last issue of GR-1221 Fully aligned vibration and impact requirements to simplify testing Used with GR-1209, Issue 4, Generic Requirements for Passive Optical Components, these documents assure that optical devices function satisfactorily for long periods under adverse environmental conditions.