Fig. 1. Structure of the multi-mode multiplexer/de-multiplexer

Fig. 2. Schematic of multi-mode multiplexer/de-multiplexer. (a) Structure of coupling area; (b) cross section of coupling area

Fig. 3. Coupling ratio as a function of core distance. (a) Coupling ratio of LP21 mode and LP02 mode as a function of core distance d2; (b) coupling ratio of LP11 mode as a function of core distance d1

Fig. 4. Coupling length as a function of core distance

Fig. 5. Power of LP01, LP11 and LP02 modes as a function of the propagation distance with the wavelength of 1550 nm

Fig. 6. Two-dimensional sketch of power flow for mode multiplexer with the wavelength of 1550 nm

Fig. 7. Coupling ratio of LP02 and LP11 modes as a function of wavelength

Fig. 8. Tolerance analysis of multi-mode multiplexer/de-multiplexer. (a) Coupling ratio of LP11 mode as a function of core distance d1; (b) coupling ratio of LP02 mode as a function of core distance d2