Two-Wave Multi/Demultiplexer on the Base οf Gradient Index Multimode Interference Structures Made by $Ag^{+}-Na^{+}$ Ion Exchange

The paper presents optimizing investigations by the beam propagation method method of two-wave multi/demultiplexer which uses gradient index multimode interference structures made by $Ag^{+}-Na^{+}$ ion exchange in BK-7 glass. We have discussed the influence of the structure geometry and technological process parameters for selected wavelength combinations within the range of 635÷ 850 nm. We have described operating parameters of the multiplexers - excess losses and contrasts. We have also presented the way of finding approximate MMI section widths and lengths which satisfy the multiplexing condition.