An InP optical 90°hybrid based on a×4 MMI coupler with a deep ridged waveguide is designed and fabricated.The working principle of the 90°hybrid is systematically introduced.Three-dimensional beam ropag...An InP optical 90°hybrid based on a×4 MMI coupler with a deep ridged waveguide is designed and fabricated.The working principle of the 90°hybrid is systematically introduced.Three-dimensional beam ropagation method(3D BPM)is used to optimize the structure parameters of the 90°hybrid.The designed compact structure is demonatrated to have a low excess loss less than-0.15 dB,a high common mode rejection ratio better than 40 dB,and a low relative phase deviation less than±2.5°.The designed hybrid is manufactured on a sandwitched structure deposited on an InP substrate.The measured results show that the common mode rejection ratios are larger than 20 dB in a range from 1520 nm to 1580 nm.The phase deviations are less than±5°in a range from 1545 nm to 1560 nm and less than±7°across the C band.The designed 90°optical hybrid is suitable well for realizing miniaturization,high-properties,and high bandwidth of coherent receiver.展开更多
In recent years, the silica-on-silicon based multimode interference （MMI） optical waveguide is an interesting research topic. It is being advanced various researches on the silica based MMI coupler. This paper repre...In recent years, the silica-on-silicon based multimode interference （MMI） optical waveguide is an interesting research topic. It is being advanced various researches on the silica based MMI coupler. This paper represents the considerations of the optimal design of the silica-on-silicon based MMI optical coupler for better performance. For that, we have illustrated the simulation results on a particular case of the 4x4 silica-on-silicon based MMI coupler. From the simulation results, it is seen that the performance of the MMI coupler depends on multiple width and length combinations of the MMI waveguide. The results also show that the width of the multimode waveguide could not be too small or too large for optimal performance, and at the widths, 100~tm, 120~tm and 130~tm, the performance could be optimized and be almost 0.62 - 0.64 in a given length range. Finally, the results have been compared with the optical coupler presently available in the market and show that the silica-on-silicon based MMI coupler is much more efficient in terms of losses and the performance associated with it and the size of the coupler.展开更多
The experimental results of a 2x2 integrated thermooptic Mach-Zehnder interferometer(MZI)switch based on multimode interference(MMI)couplers are reported.The insertion loss(IL)is 3.40 dB,the polarization dependent los...The experimental results of a 2x2 integrated thermooptic Mach-Zehnder interferometer(MZI)switch based on multimode interference(MMI)couplers are reported.The insertion loss(IL)is 3.40 dB,the polarization dependent loss is 0.47 dB,the extinction ratio(ER)at bar state and cross state is 32.01 dB and 16.42 dB respectively,the response time is less than 3 ms,and the power consumption is 658 mW.Regarding the asymmetry of extinction ratio at bar state and cross state,theoretical analysis is first presented.The coupling ratio of the two MMI couplers deviates from 50׃50 but the deviation is nearly the same,which is decided by good uniformity of semiconductor planar lightwave circuit(PLC)process.This property affects the extinction ratio at bar state and cross state in different mechanisms.Adding a metal electrode on the waveguide affects its effective index and analysis based on experimental results is given.The increment of waveguide effective index is in the order of 2x10^(-4).展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2016YFB0402404)the Beijing Natural Science Foundation,China(Grant No.4194093)the National Natural Science Foundation of China(Grant Nos.61635010,61674136,and 61435002).
文摘An InP optical 90°hybrid based on a×4 MMI coupler with a deep ridged waveguide is designed and fabricated.The working principle of the 90°hybrid is systematically introduced.Three-dimensional beam ropagation method(3D BPM)is used to optimize the structure parameters of the 90°hybrid.The designed compact structure is demonatrated to have a low excess loss less than-0.15 dB,a high common mode rejection ratio better than 40 dB,and a low relative phase deviation less than±2.5°.The designed hybrid is manufactured on a sandwitched structure deposited on an InP substrate.The measured results show that the common mode rejection ratios are larger than 20 dB in a range from 1520 nm to 1580 nm.The phase deviations are less than±5°in a range from 1545 nm to 1560 nm and less than±7°across the C band.The designed 90°optical hybrid is suitable well for realizing miniaturization,high-properties,and high bandwidth of coherent receiver.
文摘In recent years, the silica-on-silicon based multimode interference （MMI） optical waveguide is an interesting research topic. It is being advanced various researches on the silica based MMI coupler. This paper represents the considerations of the optimal design of the silica-on-silicon based MMI optical coupler for better performance. For that, we have illustrated the simulation results on a particular case of the 4x4 silica-on-silicon based MMI coupler. From the simulation results, it is seen that the performance of the MMI coupler depends on multiple width and length combinations of the MMI waveguide. The results also show that the width of the multimode waveguide could not be too small or too large for optimal performance, and at the widths, 100~tm, 120~tm and 130~tm, the performance could be optimized and be almost 0.62 - 0.64 in a given length range. Finally, the results have been compared with the optical coupler presently available in the market and show that the silica-on-silicon based MMI coupler is much more efficient in terms of losses and the performance associated with it and the size of the coupler.
文摘The experimental results of a 2x2 integrated thermooptic Mach-Zehnder interferometer(MZI)switch based on multimode interference(MMI)couplers are reported.The insertion loss(IL)is 3.40 dB,the polarization dependent loss is 0.47 dB,the extinction ratio(ER)at bar state and cross state is 32.01 dB and 16.42 dB respectively,the response time is less than 3 ms,and the power consumption is 658 mW.Regarding the asymmetry of extinction ratio at bar state and cross state,theoretical analysis is first presented.The coupling ratio of the two MMI couplers deviates from 50׃50 but the deviation is nearly the same,which is decided by good uniformity of semiconductor planar lightwave circuit(PLC)process.This property affects the extinction ratio at bar state and cross state in different mechanisms.Adding a metal electrode on the waveguide affects its effective index and analysis based on experimental results is given.The increment of waveguide effective index is in the order of 2x10^(-4).
