16 Tips to Troubleshoot Your Optical Transceiver Issues

It’s no secret that a solid and stable Internet connection is more important than ever in today’s world. With 5G, loT, and cloud data centers becoming more prevalent, the need for a dependable connection will only grow. And as part of the Internet infrastructure, optical transceivers play a vital and irreplaceable role. So, if you’re upgrading or replacing equipment and your network goes down, there’s a good chance that the problem lies in a piece of hardware. Before troubleshooting the issue, please look at our 16 tips for troubleshooting your optical transceiver connections.

Tip #1: How can we distinguish between the SFP module’s RX and TX ports?

The triangle indicates the Tx (transmit) port with the pole facing outward on the SFP module, whereas the triangle indicates the Rx (receive) port with the bar facing inside. When connecting the SFP, we must ensure that Tx and Rx, or Tx –> Rx and Rx –> Tx, match on both sides.

Tip #2: Why the LED of the switch slot does not light up after inserting the transceiver?

It may cause by two reasons: compatibility issues and physical connection issues. If you have not inserted the SFP/SFP+/XFP transceiver module into the switch slot correctly, it or link loss. The first thing you should do is re-plug the optical module into the switch slot and make sure it is firmly inserted. If the problem persists, please check the compatibility of the optical module with your switch.

Tip #3: Why is there no link after connecting two switches with the transceiver?

When connecting two switches using the optical transceiver, please ensure that they are of the same type, with the same wavelength and data rate, then recheck the connection between them.

Tip #4: What should I do when the optical power is abnormal?

First, we must determine if the optical power is too high or too low. If the optical power is too high, it will cause signal distortion, packet loss, and even damage to the optical module. If the optical power is too low, it will cause the receiving end to receive a weaker signal and affect data transmission. Therefore, adjusting the optical power within a specific range is necessary. Ensure use of the transceiver with proper link distance. Also, the optical transceiver with digital diagnostic monitoring (DDM) can help you monitor the real-time optical power.

Tip #5: How to deal with a “no light” issue?

There are several reasons for “no light” issues: incompatible SFP module, incorrect connection, SFP module not powered on, or bad SFP.

• Incompatible SFP: Please check the compatibility of your optical transceiver with your equipment.
• Incorrect connection: Please check the connection between the optical transceiver and your equipment. Make sure the Tx port of the optical transceiver is connected to the Rx port of the equipment, and the Rx port of the optical transceiver is connected to the Tx port of the equipment.
• SFP module not powered on: Please check whether the optical transceiver is inserted correctly into the switch slot and whether it is turned on.
• Bad SFP: If the above three reasons are excluded, then the optical transceiver may be defective, and you will need to replace it.

Tip #6: Why do the switch ports frequently shut down after working for some hours?

The switch port may be faulty, or the optical transceiver may be overheated. If the optical transceiver is overheated, it will cause the switch port to shut down. Please check whether the optical transceiver is appropriately ventilated and cooled. If the problem persists, please replace the optical transceiver.

Tip #7: What should I do if the optical transceiver is not recognized?

Incompatible issues may cause this problem. Ensure you buy an original optical transceiver or compatible transceiver because some mainstream switch vendor locks their transceiver port to prevent the use of third-party transceivers. In this case, you need to contact the switch vendor for help.

Tip #8: What should I do if the link is intermittent?

This problem may be caused by poor contact, and we need to check whether the optical transceiver is correctly inserted into the switch slot. In addition, it prevents whether the optical interface is dirty. If so, clean it with a fiber optic cleaner. Please replace the optical transceiver if the above two methods do not work.

Tip #9: Don’t insert 1G SFP transceiver on the SFP+ port, or insert 10G SFP+ transceiver on 1G port.

SFP and SFP+ transceiver seems the same in appearance, but they have different speed and different applications. 1G SFP transceiver is only for 1G Ethernet, and 10G SFP+ transceiver is only for 10G Ethernet. If you insert the 1G transceiver on the 10G SFP port or vice versa, it will not work.

Tip #10: How to view SFP transceiver optical power?

For SFP optical modules with a digital interface (DDM), you can use the DDM function of your equipment to monitor the real-time optical power. For SFP optical modules without DDM function, you can use an optical power meter to test the optical power of the transceiver.

 Tip #11: Ensure the fiber optic cable works properly

If the optical transceiver and the connection between the optical transceiver and your equipment are normal, but there is still no light, please check whether the fiber optic cable is working correctly. You can use an optical fiber visual fault locator (VFL) to test whether the fiber is broken. If the fiber is damaged, please replace the fiber optic cable.

Tip #12: Ensure to use the correct fiber optic cable

Use the optical transceiver along with the correct fiber optic cable. For instance, a multimode optical transceiver should be used with a multimode fiber optic cable, and a single-mode optical transceiver should be used with a single-mode fiber optic cable. If you use the wrong type of fiber optic cable, it will not work.

Tip #13 Have optical output but fails to connect

This failure is usually because the fiber end face is dirty or too long a transmission distance.

– Clean the end face of the optical module with an optical fiber cleaning pen;

– If the optical power at the receiving end is too low, it may be caused by too long a transmission distance. You can use an optical amplifier or try a long-reach optical transceiver to solve this problem.

Tip #14 Ensure the optical receiver is not Overload

For example, a 10G SFP+ ZR transceiver output very high optical power, and it will cause an Overload to the receiver for a very short distance if there is no added optical attenuator. So, it would help if you used an optical attenuator to reduce the optical power to an average level.

Tip #15 Ensure the correct wavelength for BiDi Transceiver

Unlike the regular optical transceiver, the BiDi transceiver transmits and receives data on the same fiber using different wavelengths. So, you should ensure that the wavelength of the transmitting end is consistent with the wavelength of the receiving end. Otherwise, it will not work.

Tip #16 Ensure the transceiver voltage is correct

The voltage is not a problem for most transceivers like SFP, SFP+, XFP, and QSFP+ optics because MSA defines the standard voltage. But for a 1×9 transceiver, it’s easy to have a voltage problem because there is two voltage of 3.3v or 5v. So, you should check the voltage of the transceiver and ensure it meets your system requirements.

Conclusion

Optical transceivers are delicate devices and need to be handled with care. Following the tips above can avoid many common problems and ensure that your optical transceiver works appropriately.

If you have followed the tips above and your optical transceiver still does not work, please contact us. We will be happy to help you troubleshoot the issue.