A complete collection of test items for high-quality optical modules

In order to ensure the quality of optical module products, strict testing and quality inspection procedures such as incoming material inspection, parameter inspection, aging test, real machine test, and end-face inspection will be carried out before shipment. The results of all test items must reach the standard level, otherwise Optical modules will be returned to the production line for readjustment. But do you know all about these tests? In this article, follow Transcom to take a look at those optical module tests.

1. Material inspection, patch inspection

Before assembling the optical module, a material inspection and patch inspection will be carried out. Material inspection refers to the quality confirmation and inspection of raw materials and devices, such as testing optical transmitting components (TOSA), optical receiving components (ROSA), and optical transmitting and receiving components (BOSA), to ensure the quality of finished optical modules. Materials that meet the standard will be rejected. SMT inspection is mainly to detect whether the PCB board is mounted correctly or if there is pollution, so as to ensure the performance of the optical module.

2. Optical power detection

The power of the optical module generally refers to the output power of the optical module, that is, the average output optical power of the light source at the sending end of the optical module also called the output optical power, which is an important parameter that affects the transmission distance of the optical module. When the transmitted optical power is too small, the received optical power at the receiving end of the module will be lower than the receiving sensitivity, and the module will not be able to receive signals normally; when the transmitted optical power is too large, the required bias current will be too large, which will affect the signal transmission quality and the module. service life.

3. Extinction ratio and light modulation amplitude test

The extinction ratio refers to the ratio of the optical power of the high-level (that is, all "1" codes) and low-level (that is, all "0" codes) output by the laser. The larger the extinction ratio, the larger the relative amplitude, the stronger the ability to accept and distinguish the optical signal, and the higher the receiving sensitivity. The test can detect whether the laser works in the optimal bias electric point and the optimal modulation efficiency range. Optical Modulation Amplitude (Optical Modulation Amplitude) is a measure of the power difference when the laser is turned on and off.

4. Bit error rate and receiving sensitivity test

Bit error rate (BER：biterror) refers to the ratio of the number of errored code elements received after the photoelectric conversion at the receiving end within a specified time to the number of code elements given by the output end of the bit error meter. Due to problems such as attenuation and dispersion, bit errors are prone to occur, and there is a bit error rate if there is a bit error. Receiver Sensitivity (Receiver Sensitivity) refers to the minimum received optical power of an optical module under a certain rate and bit error rate.

5. Wavelength test

Communication can be established only when the optical modules used on both ends of the equipment have the same emission and reception wavelengths. Using a spectrum analyzer and other instruments to measure the center wavelength of the optical module usually deviates from the standard value. Different types of optical modules have different deviations. If If the tested value is not within the allowable range, the optical module is regarded as a defective product.

6. High and low-temperature aging test

The high and low-temperature aging test is to simulate extreme conditions to verify the working performance of the optical module. It can compare the differences in optical power, extinction ratio, sensitivity, and other parameters between normal temperature and high and low temperature, thereby reducing the scrap rate and ensuring the working stability of the optical module.

7. Compatibility test

Compatibility refers to the degree to which hardware and software work in harmony with each other. The optical module compatibility information is different from the device information, and there will be incompatibility problems on different devices. Insert the optical module into the switch of the corresponding brand for testing, check its working status, and if there is no abnormality in the communication, it is compatible. Transcom optical modules will be tested for switch compatibility before shipment to ensure 100% compatibility.

8. End-face inspection

Optical module end-face cleaning is very important to ensure the transmission performance of the entire optical fiber system. In the optical module production process, the optical module is inserted into the equipment or instrument, and the end face of the module is inspected for dirt and scratches through a microscope to avoid cross-contamination. If there is dirt or scratches, it needs to be cleaned.

9. Eye diagram test

Eye diagram analysis is at the heart of signal integrity analysis for high-speed interconnect systems. The influence of intersymbol crosstalk and noise can be observed from the eye diagram, which reflects the overall characteristics of the digital signal, so as to estimate the quality of the system. In ideal conditions such as no intersymbol talk and noise, what you see on the oscilloscope is the clear "eye" of the trace.

10. Real fiber test

Conclusion

In addition to the above test items, there is also a real fiber test to test the distance of the optical module to ensure that there will be no signal instability or packet loss during use. The above is the entire content of this article. Transcom strictly controls the quality of optical modules, ensures rigorous testing, and provides you with high-quality and safe optical module products. Please rest assured to buy! For more product information, you can move to the official website for detailed inquiries, thank you for your support!