Author Affiliations
School of Communication and Information Engineering, Chongqing University of Posts and Telecommunications, Chongqing 400065, Chinashow less
Fig. 1. Structure diagram of non-uniform MMI
Fig. 2. Optical field patterms of the first four guided modes in uniform and non-uniform MMIs. The first guided mode in (a) the uniform MMI and (b) the non-uniform MMI; the second guided mode in (c) the uniform MMI and (d) the non-uniform MMI; the third guided mode in (e) the uniform MMI and (f) the non-uniform MMI; the fourth guided mode in (g) the uniform MMI and (h) the non-uniform MMI
Fig. 3. Distribution of the optical field intensity at the end of the uniform MMI
Fig. 4. Distribution of the optical field intensity at the end of the non-uniform MMI
Fig. 5. Distribution of the optical field intensity at the end of the non-uniform MMI after tuning the refractive index
Fig. 6. Schematic diagram of the mode splitter. (a) 3D structure diagram; (b) top view; (c) cross-section diagram
Fig. 7. Transmission spectra of the output ports. (a) Output2; (b) output1; (c) output3
Fig. 8. Transmission spectra of the output ports after optimization again. (a) Output2; (b) output1; (c) output3
Fig. 9. Light field diagrams of each mode. (a) TE0; (b) TE1; (c) TE2
Fig. 10. Schematic diagram of the chip process (EBL: electron beam lithography, ICP: inductively coupled plasma etching, PECVD: plasma enhanced chemical vapor deposition)
Fig. 11. Variation ranges of insertion loss and crosstalk of mode splitter under different temperature deviation range. (a) Insertion loss; (b) mode crosstalk
Mode | Mode1 | Mode2 | Mode3 | Mode4 | Mode5 | Mode6 | Mode7 | Mode8 | Mode9 | Mode10 |
---|
TE0 | 0.078 | 0.144 | 0.189 | 0.208 | 0.200 | 0.170 | 0.126 | 0.078 | 0.033 | 0 | TE1 | -0.038 | -0.063 | -0.067 | -0.045 | 0 | 0.058 | 0.119 | 0.168 | 0.197 | 0.200 | TE2 | 0.025 | 0.041 | 0.042 | 0.027 | 0 | -0.029 | -0.052 | -0.056 | -0.056 | 0 |
|
Table 1. Excitation coefficients of the first 10 guided modes in a uniform MMI
Mode | Mode1 | Mode2 | Mode3 | Mode4 | Mode5 | Mode6 | Mode7 | Mode8 | Mode9 | Mode10 |
---|
TE0 | 0.133 | 0.887 | 0.134 | -0.171 | 0.132 | -0.136 | -0.117 | 0.052 | -0.015 | -0.046 | TE1 | 0.004 | -0.002 | 0.044 | -0.200 | 0.047 | -0.117 | -0.203 | 0.190 | 0.192 | 0.196 | TE2 | 0.001 | 0.085 | -0.027 | -0.081 | -0.014 | 0.034 | 0.040 | -0.034 | -0.025 | 0.017 |
|
Table 2. Excitation coefficients of the first 10 guided modes in non-uniform MMI
Ref. No | Structure | Mode separation counts | Insertion loss /dB | Cross talk /dB | Bandwidth /nm | Mode maintenance function |
---|
[13] | MMI | 3 | <1.18 | <-20 | — | No | [14] | Y-junction | 2 | <0.56 | <-9.1 | 106 | No | [16] | CTC | 4 | <4.73 | <-15.15 | 66 | No | [17] | MMI | 2 | <1.1 | <-18 | 120 | No | [3] | MMI | 3 | <1.1 | <-10 | 90 | No | This work | MMI | 3 | <1.06 | <-15.38 | 97 | Yes |
|
Table 3. Performance comparison of different mode splitter schemes