Posted in Article, Optical Transceiver

Guide to Fiber Optic Transceiver Testing

Fiber optic transceiver is an important component of optical network converting electrical signals to optical signals or the same thing in reverse. The performance of a transceiver is vital to the function of whole system. If its compatibility and interoperability are assured, there will be less problems for practical applications. A reliable vendor will first verify the performance of transceivers before putting them into the market. But how much do you know about the testing process of fiber optic transceiver?

transceiver-testing

As we know, fiber optic transceiver is a single, packaged device composed of a transmitter and a receiver. Poor quality transceivers will affect the operation of entire network. Therefore, the testing of transmitter optical power and receiver sensitivity are absolutely necessary. This post will guide you to know the basics of transmitter and receiver testing for fiber optic transceivers. From the following figure, you may have an overview of the main measurement process.

transceiver-tesing-process

Transmitter Testing

The transmitter port of an optical transceiver consists of a light source and relevant electronic circuitry. Measurement for the transmitter is a typical production test performed to ensure that the transmitter performs at a specified level. Here are two steps to test a transmitter:

  • Step one, the input signal must be good enough when testing a transmitter. Measurements of jitter and an eye mask test must be performed to confirm the quality. An eye mask test is the common method to view the transmitter waveform and provides a wealth of information about overall transmitter performance.
  • Step two, the optical output of the transmitter must be tested using several optical quality metrics such as a mask test, OMA (optical modulation amplitude), and extinction ratio.
Receiver Testing

The receiver port of an optical transceiver is composed of a photodiode that performs the optical-to-electrical conversion and electronic circuitry to correctly interpret the bits received. Receiver is tested within reasonable gating time at higher BER (bit error ratio). Here are two steps for receiver testing:

  • Step one, the receiver testing involves sending in a signal that has poor quality. To do this, a stressed eye representing the worst case signal shall be created. This is an optical signal, and must be calibrated using jitter and optical power measurements.
  • Step two, testing the electrical output of the receiver should be processed. Three basic categories of tests are included. First is the mask test. It ensures a large enough eye opening accompanied by a BER depth. Second is the jitter budget test which tests for the amount of certain types of jitter. Third is the jitter tracking and tolerance. This is performed to measure the ability of the internal clock recovery circuit to jitter within its loop bandwidth.
Summary

All in all, fiber optic transceiver testing is essential to the performance of network system. Today, most produced transceivers are tested based on the above parameters to make sure that they are fully complied with the required specifications. The widely used eye-mask test is an effective way to test a transmitter. But testing a receiver may seem much more complicated because of the requirements for multiple testing methods. Our website provides full series of fiber optic transceivers. Each transceiver is tested to be 100% compatible to your network. Please search at our site for more information.

Source:http://www.sfp-transceiver-modules.com/wiki/a/110/Guide-to-Fiber-Optic-Transceiver-Testing

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