Fast Facts: Bi-Di optical transceivers

14 December 2018

What are Bi-Di optical transceivers?

Bi-Di is a shortened version of ‘Bi-Directional’. Bi-Di optical transceivers got their name due to their technology of using a bidirectional coupler to transmit and receive signals. This means that instead of the conventional transceiver where there are 2 ports used to send data (the TX for the transmit port and the RX for receive port), the Bi-Di optical transceiver transmits and receives using a single port, over a single fibre.


BIDI SFP Mechanical Drawing
SFP Bi-Di Mechanical Drawing


How do Bi-Di transceivers work in the telecom network?

Bi-Di transceivers need to be in matched pairs when used. The couple are adjusted to use two different wavelengths in order to send and receive data. For example, if there are two matched Bi-Di transceivers deployed, the transmit wavelength of Transceiver 1 must be the same as the receiving wavelength of Transceiver 2 and vice versa. Typically the wavelengths used for the up and downstream are 1310/1550 and 1270/1330. Because of this ability to both transmit and receive data, the optical subassembly is also different to a standard transceiver. The common transceiver includes a two-part optical subassembly. This being TOSA (Transmitter Optical Subassembly) and ROSA (Receiving Optical Sub-Assembly). While the Bi-Di uses BOSA (Bidirectional Optical Sub-Assembly) to replace the need for both.


Business Case for Bi-Di Transceivers in the telecoms network

Clearly where it is possible to go up and downstream over a single fibre using different wavelengths, the telecom operator is able to make a considerable commercial saving. This is because the cost of laying new fibre is considerable. Also, once it has been deployed it can be used more efficiently using bidi transceivers. This means that the operator can achieve double the capacity from existing fibre plant thereby unlocking considerable savings.



Bi-Di transceivers are available from TXO for 1G, 10G and 40G transmission using SFP/ SFP+ / XFP and QSFP form factors.


Testing of Bi-Di transceivers for telecoms use

TXO’s range of BiDi modules are compatible with all of the major brands and are fully tested in our in-house test lab. TXO’s test lab has a huge range of devices for interoperability testing of Bi-di transceivers. Brands include Juniper, Huawei, Arista, Extreme and so on. In addition, some Bi-di transceivers for legacy brands such as Lucent are difficult to obtain, TXO is also able to help with such cases. As usual, in addition to interoperability testing in the intended device TXO also performs the standard optical tests in our lab to ensure client satisfaction.


Browse our range of Bi-Di transceivers today

TXO Optics have a huge range of compatible Bi-Di modules on offer including the following:

3FE53441BA-TX – Alcatel compatible SFP Bi-Di 1000BASE GPON 1490nm/1310nm 20km transceiver

SFP-10G-BX40D-I-TX – Cisco compatible SFP+ Bi-Di 10GBASE 1310nm/1270nm 40km SM transceiver

XCVR-040U31-TX – Ciena compatible SFP Bi-Di 1000BASE 1310nm/1550nm 40km SM transceiver

For more information on our Bi-Di optical transceivers or for a 30-day free trial, contact us using the buttons below or call +44 (0)1291 623 813.