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NTC Thermistor Improves Circuit of Poor Tracking Error of Optical Module-1
2019/02/19 03:02:22

NTC Thermistor has fast response, high cost performance, good stability and other characteristics, widely used in bonding, sensors, circuit boards and so on. The NTC thermistor produced by EXSENSE Electronic Technology Co., Ltd. adopted advanced semi-conductor processing system, combined with proprietary intellectual property rights of the NTC thermistor materials and processing technology, to achieve the high-precision and batch manufacturing of NTC thermistor. Now, we will introduce the role of NTC thermistor in optical module.


In the optical module, due to the optical transmitting device TOSA or optical transceiver device BOSA has the situation of high-low-temperature tracking error inevitably. Tracking error refers to the ratio of the optical fiber output power at two different temperature conditions, it’s the parameter to measure the coupling efficiency stability of the device, the unit is dB.


The output light power of the optical module is usually adjusted to a fixed value at room temperature (usually 25℃) before shipment. Because the tracking error TE phenomenon exists, when the optical module is worked, high-temperature environment or its own work produces heat and raises the temperature, resulting in a quite number of optical module products of high-low-temperature tracking error power less than the normal working requirements of the range in the high temperature, the product can’t be used will cause waste of TOSA or BOSA, increase cost of production.

In order to overcome the shortcomings in the existing technology, a method to improve circuit of poor tracking error of optical module is provided. This method enables the optical module output light power to become smaller than the normal working requirement in the high temperature time to reach the required range, avoids the waste of TOSA or BOSA devices, and saves the production cost.


The method includes laser driver chip, laser driver chip is connected to laser, the laser driver chip is connected to optical power first thermistor, optical power first thermistor is NTC thermistor RNTC. At room temperature 25℃, the resistance value of thermistor RNTC is 50KΩ, at high temperature 90℃, the resistance value is 8KΩ, the resistance value of NTC thermistor RNTC decreases gradually with the increase of temperature.

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