WHAT IS A BIDIRECTIONAL OPTICAL WDM BIDI TRANSCEIVER?

Commonly, optical networks rely on Transceivers that utilize one optical fiber to transmit data and another optical fiber to receive data to and from the networking devices. Generally, this kind of data transmission raises the costs of the network deployment, however with use of the bidirectional optical WDM BIDI Transceiver, and its capability to send and receive data over one optical fiber, we can create a much more cost-effective optical networks.

 

The Bidirectional Optical Transceiver or BIDI, is a type of an optical Transceiver which uses the Wavelength Division Multiplexing technology or widely known as WDM technology. The BIDI Transceiver manages to do this with the help of the integral bidirectional coupler which transmits and receives signals.

 

The main difference that differentiates BIDI Transceivers from standard, two fiber Transceivers, is the possibility of the BIDI Transceiver to send and receive optical light data through a single fiber. This is easily illustrated in the pictures below which offer a side to side comparison between these two types of Transceivers. The other key difference between the standard and BIDI Transceiver is the introduction of Wavelength Division Multiplexing technology incorporated into BIDI Transceivers. This technology separates the data sent and received over the same fiber based on the wavelengths of the light. However, to work at maximum level, the BIDI Transceiver must be deployed in matched pairs and tuned to match the expected wavelength of the transmitter and receiver they are transmitting and receiving data from and to. To put things in perspective, if one Transceiver is transmitting wavelengths of 1310 nm, the other side must have a receiving wavelength of 1310 nm and vice-versa.

 

The common types of BIDI Transceivers used in today’s networks are:

 

Bidirectional optical X2 Transceiver – Firstly designed for 10GB serial data communications. This transceiver is made of two sections with the transmitter part using a multiple quantum 1330/1270 nm Distributed Feedback Laser. The receiving part of the transceiver uses an integrated detector with preamplifier for 1270/1330 nm. This optical transceiver is mainly used in Ethernet solutions. Primarily used in older networking equipment.

 

Bidirectional optical SFP Transceiver – this transceiver is most commonly deployed in high speed duplex data links over a single optical fiber. The most common optical wavelengths for this transceiver is 1310/1490 nm, 1490/1550 nm and 1310/1550 nm. Today this type of transceivers is used in optical communication for optical gigabit telecommunications and optical data bidirectional applications as follower of the GBIC Transceiver.

 

Bidirectional optical SFP+ Transceiver – This type of transceiver is a more advanced version of the BIDI SFP Transceivers. SFP transceiver. It is designed for 10 GB deployment and distances up to 80 kilometers. Bidi variants are also available for the form factor XFP.

 

Bidirectional optical QSFP Transceiver – This transceiver most commonly has two 20 GB/s channels with each transmitted and received at the same time over a single Multi-mode strand (OM3 or OM4).

 

The obvious advantage of using Bidirectional Transceivers is simple. Reducing the fiber optic cable infrastructure, reducing the number of patch cords and panels and thus reducing the overall cost of the Network Solution. Even though Bidirectional Optical Transceivers cost more to purchase them, deploying them will eventually result in cutting down half of the amount of fiber per distance needed for a certain project.

 

Today the Bidirectional Optical Transceivers are mainly used in FTTH/FTTB active Ethernet point-to-point connections. These connections consist of a central office, or premises equipment (PE), connecting to the CPE or widely known as Customer Premises Equipment. Active Ethernet solution uses the point-to-point technology in which each customer is connected to the PE on a dedicated fiber. In this case the use of BIDI Transceivers is essential because it provides a bidirectional communication over a single fiber by using the WDM technology making the connection simpler to deploy, troubleshoot and configure.