The vast majority of optical transceivers on the market utilize a pair of fiber optic cables; one to transmit data and the other to receive data. However, you may have heard of bidirectional optical transceivers (or BiDi for short) and wondered what these were, how they work, and what benefits do they offer. These are the questions we will consider in this blog.
What are BiDi optical transceivers and how do they work?
From a functional perspective, BiDi optical transceivers are the same as regular ones. The main difference is that BiDi optics will only use a single fiber optic cable instead of two. The regular optics will use one fiber optic cable to transmit and the other to receive using the same wavelength (1310nm, 1550nm, etc.). In contrast, the BiDi optics will do both functions, transmit and receive, on the same fiber optic cable but using different wavelengths for each function (e.g. 1310nm for TX and 1490nm for RX) and using WDM (Wavelength Division Multiplexing) to transport both wavelengths on the same fiber optic cable.
In order to function correctly, BiDi optics usually operate in pairs and for the most part are typically sold as such also. To illustrate this point better, consider the diagram below. BiDi Device A will use 1310nm to transmit and 1490nm to receive while at the opposite end, its paired BiDi Device B will use 1310nm to receive and 1490nm to transmit. This setup will ensure that each TX-RX link (from A to B and from B to A) is operating on the same wavelength and will function correctly.
Benefits of BiDi optical transceivers
The main benefit of utilizing BiDi optics is the reduction of the number of fiber optic cables needed in the network. While BiDi transceivers will cost more to purchase initially, the cost savings that come from using half the optic fiber cables will often more than offset the higher initial purchase price. These cost savings come from reducing the number of patch panel ports used, less cables to route and manage and lower tray space usage.
Common types of BiDi optical transceivers
The most common types of BiDi optics are BiDi SFP most typically used for rates up to 1G and BiDi SFP+ used for rates up to 10G. The BiDi SFP optics will commonly use 1310nm/1490nm or 1310nm/1550nm wavelength combinations whereas the BiDi SFP+ optics will typically use 1270nm/1330nm wavelength combination. In both case, these optics are available in different reach distances and can go up to 80km transmission distance making them suitable for different applications.
GigOptics - Your Trusted Supplier for Optical Transceivers
At Gigoptics, we offer a wide range of optical transceivers to meet the requirements of various application; all tested to ensure quality and reliability. For more information about BiDi optical transceivers or to request a quote, contact us at info@gigoptics.com.