An eight-channel wavelength-mode-division (de)multiplexer based on photonic crystals

摘要

With the rapid development of data services, the speed of IP network convergence is accelerating. It is particularly important to expand the capacity of the network. The combination of wavelength division multiplexing (WDM) and mode division multiplexing (MDM) can double the system capacity and spectral efficiency. In the wavelength-mode-division multiplexing (WMDM) system, the wavelength-mode-division (de)multiplexer is the core device. A wavelength-mode-division (de)multiplexer based on photonic crystals is proposed in this paper. The device is integrated on a photonic crystal chip. According to the time-domain coupled mode theory, the filter is realized by using the structure of point-defect cavity and wavelength-selective reflection cavity. According to the transverse coupled mode theory, the mode conversion is realized by using the asymmetric parallel waveguide (APW). The finite-difference time-domain method (FDTD) is used to analyze the performance of the device. The simulation results show that the device can multiplex and de-multiplex eight channel signals, including TE0, TE1, TE2 and TE3 modes of 1540 nm and 1550 nm. The (de)multiplexer has low insertion loss (<0.38 dB) and crosstalk (<-15.87 dB), which plays an important role in the WMDM system, is of great value to enhance the capacity of optical communication system.