Design and verification of a miniaturized high density WDM array device

With the improvement of network rate, whether it is in the access network, transmission network, data center, intelligent computing center, multi-wavelength transmission has been more and more applications, the recent development of optical frequency comb technology has become a hot spot in the industry, a single optical device at the same time to send multi-wavelength signals become possible, with the increase in the number of wavelengths, the wavelength division multiplexing device will produce new demand, At present, WDM devices mainly include TFF thin film filter type and waveguide type. The advantages of TFF thin film filter type WDM are small insertion loss, high isolation, large bandwidth, cheap price and high reliability. The disadvantages are that lens convergence is required and the size is large. The disadvantages of PLC type are high insertion loss, low bandwidth and low isolation, which need to be cascaded to improve isolation. In this paper, a miniaturized and highly density WDM array device is proposed. Combining the advantages of TFF thin film filter and waveguide WDM, we simulate and design a group of Y-type PLC waveguide array, and open a 25um wide slot at the Y waveguide node by means of slice. The ultra-thin TFF film filter of about 20um is inserted into the slot, and the transmitted light and reflected light are derived through the transmitted waveguide and reflected waveguide to realize the WDM function. By optimizing the cone length and width at different Y junction, as well as the cutting position, we obtain that the transmitted path insertion loss is 0.77dB and the reflected path insertion loss is 1.07dB. Compared with traditional thin film filter type WDM, the number of WDM that can be placed on the same size in this scheme is more than 60 times, which greatly improves the space utilization rate, and simultaneously combines the advantages of TFF type WDM and waveguide type WDM. Subsequently, by improving the coupling accuracy, reducing the roughness of grooves or using etching method to make TFF slot, The insertion loss can be further reduced.