Author:  OEDI     2014-09-04

To meet the rapidly growing demands of transmission capacities of optical networks, the advance modulation formats combined with various multiplexing techniques are extensively utilized in the fiber optics communication nowadays. Consequently, the corresponding processing and switching techniques at the network interface were proposed and demonstrated to accommodate different multiplexing methods. Recently, polarization division multiplexing (PDM) and mode division multiplexing (MDM) have received more and more attention. However, to the best of our knowledge, there is no previous report on the conversions between PDM and MDM.

Under the guidance of Prof. Xinliang Zhang and associate Prof. Yu Yu, Mengyuan Ye, a doctoral candidate in OEDI department of WNLO, proposed a compact silicon-on-insulator device used for conversions between polarization division multiplexing (PDM) and mode division multiplexing (MDM) signals by utilizing a structure combining the improved two-dimensional grating coupler and two-mode multiplexer. The detailed design of the proposed device is presented and the results show the extinction ratio of 16 and 20 dB for X- and Y-pol input, respectively. The processing of 40 Gb∕s signal is achieved within the C-band with good performance. The proposed converter is capable of handling multiple wavelengths in wavelength division multiplexing (WDM) networks, enabling the conversions between WDM–PDM and WDM–MDM, which is promising to further increase the throughput at the network interface.

The result is published in Optics Letters (vol. 39, pp. 758-761, 2014). This work was supported by the National Basic Research Program of China (Grant No.2011CB301704), the National Natural Science Foundation of China (Grant No.61007042, 61275072 and 61125501), New Century Excellent Talent Project in Ministry of Education of China (NCET-13-0240).