Everything You Should Know About Optical Transceiver Networking

NADDOD Edward Jan 9, 2023

Have you encountered the following problems in fiber optic transmission cabling: How to connect a fiber optic transceiver that does not light up? Can a fiber optic transceiver and a switch plugged into an optical transceiver be used together? Can a dome with an optical port be used with a switch?

1. Optical Fibers

A fiber made of glass or plastic for the transmission of optical signals. The principle of transmission is ‘total reflection of light’. It has the advantages of good confidentiality, lightweight, strong anti-interference ability, long distance, and high data bandwidth. The transmission rates supported by optical fiber include 100Mbps, 1Gbps, 10Gbps, and higher.

Optical Fiber Classification

Common wavelengths used for optical fiber transmission are 850, 1310, 1490, and 1550nm, according to the mode of optical fiber transmission optical signal is divided into single-mode fiber (SMF) and multi-mode fiber (MMF).
Single-mode fibers: can only transmit one mode of light and are suitable for long-distance transmission.
Multimode optical fiber: can transmit multiple modes of light, suitable for short-distance transmission such as in the server room.

Common types of interfaces for optical fibers

2.Optical Transceivers

Responsible for photoelectric conversion, the transmitter converts the electrical signal into an optical signal, which is transmitted through the optical fiber, and then the receiver converts the optical signal into an electrical signal. Common optical transceiver rates: 155M (100 megabits), 1.25G (gigabit), 10G (10 megabits), 40G.

Classification of optical transceivers

Classification by optical transceiver mode

Single-mode: long transmission distance

Multimode: transmission distance is close, generally less than ≤ 2km

Classified by link resources

Single-fiber optical transceiver

Dual-fiber optical transceivers

3.Optical Transceiver Pairing Principle

The above method is also applicable to equipment with built-in optical transceivers!

Since optical transceivers are divided into two directions when transmitting data: transmitting and receiving, dual-fiber optical transceivers are distinguished by different ports and single-fiber optical transceivers are distinguished by different optical wavelengths, as follows.

Therefore, when using a single-fiber optical transceiver, the wavelengths of the optical transceivers at both ends should be matched, i.e. TX/RX are opposite.

Dual-fiber optical transceivers, the same type at both ends
Single-fiber optical transceivers, both ends of the optical transceiver wavelength TX and RX opposite, the other consistent.

4. Optical Transceiver Networking Method

Do I need to turn on the optical port of the switch?
Except for the optical port of the optical multiplexer, the optical port of all other switches is plug-and-play and does not need to be switched on.

How to deal with the optical port not being lit?
Common troubleshooting in four steps.

  1. Check whether the optical port of the device and the optical transceiver are used to match the rate.
  2. Check whether the optical transceivers used at both ends are paired.
  3. Check whether the optical fiber used matches the optical transceiver, single-mode optical transceivers use single-mode fiber, and multi-mode optical transceivers use multi-mode fiber

    Double fiber optical transceiver, one end of the two optical fiber left and right pair down
  4. Check whether the optical fiber link is OK, use a short fiber for testing.