Research And Design Of Optical Channel Monitoring Module Based On Tunable Filter

With the continuous development of the Internet industry, the optical fiber communication is gradually developing towards the direction of the large-capacity, high-speed and long-range. The channel spacing is becoming increasingly narrow in order to make better use of bandwidth resources. The OCM(Optical Channel Monitoring) module which could monitoring the parameters such as wavelength, power and OSNR of every optical channel emerged when the deterioration of the parameters, the monitoring and location of the fault is particularly important to equipment in multi-channel and high-speed transmission. The traditional OCM module which is based on diffraction effect is widely used because of its mature technology. However, large space is required due to diffraction, which makes the volume of diffractive OCM module quite large. And it requires a large amount of PD (Photoelectric Diode), which means its cost is high. The OCM module which is base on Interference effect, requires only one detection circuit. As a result that, the interferential OCM module is low cost and small size. However, the tunable filter, which is the key component of interferential OCM module, is not yet mature. This means that existing tunable filters is easy to aging, drift severe and has poor reproducibility, which makes that the interferential OCM module is not widely used.This paper describes the research status of the OCM technology, which includes fundamentals, characteristics and key technologies of the diffractive OCM and interferential OCM. Then give the reason why we chose the interferential OCM module. The paper start with the basic principle, gives the overall design, function modules and technical parameters of OCM module. Then details the hardware platform and software drivers and algorithm. For the problems in the immature tunable filter such as large drift, easy to aging and the requirement of high accurate driver, hardware or software solutions are proposed to design the OCM module which gets large detection range, high power and wavelength accuracy.After passing the calibration test, the performance indicators of the OCM module were tested. And they were compared with the expectations. The results displayed that the performance indicators have achieved the desired goals, and some of them even exceeded the technical indicators of internationally renowned OCM module when the light into the OCM module is between-lOdBm to -40dBm. However, when the light into the module is lower then -40dBm, the performance of OCM module is not satisfactory, indicating that the section of low light detection of OCM module could be improved.