Integrated waveguides with slot structures have attracted increasing attention due to their advantages of tight mode confinement and strong light-matter interaction.Although extensively studied,the issue of mode misma...Integrated waveguides with slot structures have attracted increasing attention due to their advantages of tight mode confinement and strong light-matter interaction.Although extensively studied,the issue of mode mismatch with other strip waveguide-based optical devices is a huge challenge that prevents integrated waveguides from being widely utilized in large-scale photonic-based circuits.In this paper,we demonstrate an ultra-compact low-loss slot-strip converter with polarization insensitivity based on the multimode interference(MMI)effect.Sleek sinusoidal profiles are adopted to allow for smooth connection between the slot and strip waveguide,resulting reflection reduction.By manipulating the MMI effect with structure optimization,the self-imaging positions of the TE0 and TM0 modes are aligned with minimized footprint,leading to low-loss transmission for both polarizations.The measurement results show that high coupling efficiencies of−0.40 and−0.64 dB are achieved for TE_(0) and TM_(0) polarizations,respectively.The device has dimensions as small as 1.1μm×1.2μm and composed of factory-available structures.The above characteristics of our proposed compact slot-strip converter makes it a promising device for future deployment in multi-functional integrated photonics systems.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
A multimode interference(MMI)structure is designed to simplify the fabrication of quantum cascade laser(QCL)phase-locked arrays.The MMI geometry is optimized with a sufficient output channel distance to accommodate co...A multimode interference(MMI)structure is designed to simplify the fabrication of quantum cascade laser(QCL)phase-locked arrays.The MMI geometry is optimized with a sufficient output channel distance to accommodate conventional photolithography and wet etching process by which power amplifier array is fabricated without using the complicated two-step etching-regrowth or dry etching technique.The far-field pattern with periodically modulated peaks reveals that the beams from the arrays are phase-locked.Furthermore,the frequency tuning performance of the MMI-based phase-locked arrays is studied using the Littrow-configuration external cavity structure.A wavelength tuning range of more than 60 cm^(−1) is demonstrated,which will eventually realize the high power,frequency tunable,large-scale phase-locked arrays,and their application in spectroscopy.展开更多
Optical switches are key components for constructing optical communication networks, so it is necessary to design optical switches and optical switch arrays with high performance and low cost. As one type of optical s...Optical switches are key components for constructing optical communication networks, so it is necessary to design optical switches and optical switch arrays with high performance and low cost. As one type of optical switches, the multimode interference（MMl） switches have received considerable attention due to their unique merits. The structures and operation principles of various types of MMI switches are introduced, and the recent progresses of MMI switches are also discussed.展开更多
基金This work was funded by the National Key Research and Development Program of China(No.2018YFB2201704)the National Natural Science Foundation of China(Grant Nos.61635001 and 62105008)+2 种基金China National Postdoctoral Program for Innovative Talents(No.BX20200017)China Postdoctoral Science Foundation(No.2021T140004)the Major Key Project of PCL(No.PCL2021A14)。
文摘Integrated waveguides with slot structures have attracted increasing attention due to their advantages of tight mode confinement and strong light-matter interaction.Although extensively studied,the issue of mode mismatch with other strip waveguide-based optical devices is a huge challenge that prevents integrated waveguides from being widely utilized in large-scale photonic-based circuits.In this paper,we demonstrate an ultra-compact low-loss slot-strip converter with polarization insensitivity based on the multimode interference(MMI)effect.Sleek sinusoidal profiles are adopted to allow for smooth connection between the slot and strip waveguide,resulting reflection reduction.By manipulating the MMI effect with structure optimization,the self-imaging positions of the TE0 and TM0 modes are aligned with minimized footprint,leading to low-loss transmission for both polarizations.The measurement results show that high coupling efficiencies of−0.40 and−0.64 dB are achieved for TE_(0) and TM_(0) polarizations,respectively.The device has dimensions as small as 1.1μm×1.2μm and composed of factory-available structures.The above characteristics of our proposed compact slot-strip converter makes it a promising device for future deployment in multi-functional integrated photonics systems.
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.
基金supported by the National Basic Research Program of China(Grant Nos.2018YFA0209103 and 2018YFB2200504)the National Natural Science Foundation of China(Grant Nos.61991430,61774146,61790583,61674144,61774150,and 61805168)+1 种基金the Beijing Municipal Science&Technology Commission,China(Grant No.Z201100004020006)the Key Projects of the Chinese Academy of Sciences(Grant Nos.2018147,YJKYYQ20190002,QYZDJ-SSW-JSC027,and XDB43000000).
文摘A multimode interference(MMI)structure is designed to simplify the fabrication of quantum cascade laser(QCL)phase-locked arrays.The MMI geometry is optimized with a sufficient output channel distance to accommodate conventional photolithography and wet etching process by which power amplifier array is fabricated without using the complicated two-step etching-regrowth or dry etching technique.The far-field pattern with periodically modulated peaks reveals that the beams from the arrays are phase-locked.Furthermore,the frequency tuning performance of the MMI-based phase-locked arrays is studied using the Littrow-configuration external cavity structure.A wavelength tuning range of more than 60 cm^(−1) is demonstrated,which will eventually realize the high power,frequency tunable,large-scale phase-locked arrays,and their application in spectroscopy.
文摘Optical switches are key components for constructing optical communication networks, so it is necessary to design optical switches and optical switch arrays with high performance and low cost. As one type of optical switches, the multimode interference（MMl） switches have received considerable attention due to their unique merits. The structures and operation principles of various types of MMI switches are introduced, and the recent progresses of MMI switches are also discussed.
