| 1. |
He Xiao, Yudai Kawano, Haisong Jiang, Kiichi Hamamoto,, The proposal of a photon–photon resonance control scheme by using an active MMI laser diode, Photonics, 10.3390/photonics10121298, 10, 12, 1298, 2023.11. |
| 2. |
Yuta Shimamura, Haisong Jiang, Ryota Kuwahata, Younjin Kim, Kensei Yamauchi, Ryoma Matsuo, Kiichi Hamamoto, Precise asymmetric power-splitter (1.7:1) by using nano-pixel waveguide, ELECTRONICS LETTERS, 10.1049/ell2.12831, 59, 11, 2023.06, Power-splitter is one of the fundamental elements for photonic integrated circuits. Y-junction, multi-mode-interference (MMI), and directional coupler may have been widely used as power splitter; however, the design theory to realize precise asymmetric splitting ratio is not well established. In addition, the device length is relatively long and less robustness in general. To realize a power splitter with a desired splitting ratio, the authors used a nano-pixel structure. Nano-pixel structures consist of an array of pixels in which the rectangular waveguide region is divided into many nano-scale regions. The implemented devices were realized in an area of 3.2 mu m x 3.4 mu m. The device exhibited precise asymmetric splitting of 1.7:1 successfully at 1550 nm.. |
| 3. |
Yunjie Wang, Haisong Jiang, Kiichi Hamamoto, Space-mode compressor by using nano-pixel, JAPANESE JOURNAL OF APPLIED PHYSICS, 10.35848/1347-4065/ac7b0e, 61, SK, 2022.08, Spatial-division-multiplexing, as a promising way to enhance the fiber transmission capacity of optical networks, has been widely researched, and still suffers from the problem of device size increasing along with the space-mode order increasing. In order to solve this problem, an optical mode field compression method is needed, however, it is difficult to realize for traditional optical waveguide. To achieve a highly dense photonic integrated circuit for the transmission of higher order space-mode, a space-mode compressor using nano-pixel structure was proposed and investigated in this work. A supervised machine learning model using a deep neural network was used to design and optimize the space-mode compressor based on nano-pixel structure. As a simulated result, we achieved possible nano-pixel configurations for the purpose of mode-compression and there is a more than 50% size compression for the 0th and 1st order modes, as well as a 39.3% size compression for the 2nd and 35% for 3rd order modes.. |
| 4. |
Shun Matsubara, Tomoya Zennouji, Haisong Jiang, Kiichi Hamamoto, Rapid automatic waveguide recognition using YOLO and OpenCV for 3D waveguide fabrication, JAPANESE JOURNAL OF APPLIED PHYSICS, 10.35848/1347-4065/ac6e57, 61, SK, 2022.08, A 3D waveguide is attractive because it has the potential that the waveguides are arranged, not only in plane, into three-dimension. The mosquito method, in which the core and cladding material sources are liquid and will be cured using UV light, is known as one of the ways to fabricate the 3D waveguide. In this method, if multiple waveguides are fabricated, the time until UV cure is different between the first waveguide and the last one and it leads to core position shift because of gravity. To solve the problem, we considered reducing the time from the first waveguide formation to the UV cure using automatic waveguide fabrication with a camera. For the automatic waveguide fabrication, YOLO (you look only once) and OpenCV are exploited as machine learning and an image processor, respectively. As a result, a waveguide recognition time of 10 ms and image processing time of 50 ms, totally 60 ms, are realized.. |
| 5. |
Zhiyuan Fan, Yasuhiro Hinokuma, Haisong Jiang, Kiichi Hamamoto, Active multi-mode interferometer semiconductor optical amplifier on quantum dots toward high saturated output power under high temperature, JAPANESE JOURNAL OF APPLIED PHYSICS, 10.35848/1347-4065/ac6a3e, 61, SK, 2022.08. |
| 6. |
Keiichiro Shoda, Xiao He, Keiichirou Koudu, Haisong Jiang, Kiichi Hamamoto, Equal input, compact optical power coupler based on a nano-pixel structure designed with machine learning, JAPANESE JOURNAL OF APPLIED PHYSICS, 10.35848/1347-4065/ac678d, 61, SK, 2022.08, A multi-mode interference (MMI) waveguide has been widely researched and developed to realize an optical power coupler. MMI coupler exhibits the superior performance of the "Equal intensity coupling" characteristics, however, it has a problem that excess loss occurs if the phase-matching condition is not satisfied at all of the input ports. The phase condition depends on the number of input ports, and relatively complicated phase control is required, thus, it is desired to realize an optical power coupler without complicated phase adjustment. In order to avoid the phase-control difficulty, a nano-pixel power coupler is investigated in this paper. The nano-pixel-based coupler has the merit of ultra-compact dimension which is close to the wavelength order, therefore, it is expected that less excess loss even under simple "equal" phase conditions. The structure was examined using FDTD and the simulated results show equal input (intensity and phase) coupling capabilities with a low excess loss of 0.11 dB.. |
| 7. |
Zhiyuan Fan, Yasuhiro Hinokuma, Haisong Jiang, Kiichi Hamamoto, Active multi-mode interferometer semiconductor optical amplifier on quantum dots toward high saturated output power under high temperature, JAPANESE JOURNAL OF APPLIED PHYSICS, 10.35848/1347-4065/ac6a3e, 61, SK, 2022.08, A semiconductor optical amplifier (SOA) is wildly used as gain media in a photonic integrated circuit, as it is integrable with various devices, including wavelength filter, on the same wafer. Quantum dots (QD) have been known to realize high-temperature operation without using a thermo-cooler, the saturated output power was not high due to the limited density of state in QD. To realize high saturated output power under high temperatures, we have exploited the active multi-mode interferometer (active-MMI) configuration on QD SOA. We fabricated active-MMI SOA using a 1.31 mu m InAs/GaAs QD active layer with the design of approximately 5 times larger footprint compared to a single stripe, whereas it holds regular single transverse mode output. As a result, a significant improvement of 15 dB saturated output power at 75 degrees C was substantiated successfully.. |
| 8. |
JIANG Haisong, NASEF Mahmoud, HAMAMOTO Kiichi, Spatial Single Dimensional Mode Based De-Multiplexer Using Slab Waveguide, IEICE Transactions on Electronics, 10.1587/transele.2020ecs6017, E104.C, 5, 164-167, 2021.05, This paper reports a single dimensional mode based multiplexer / de-multiplexer using the slab waveguide to realize high modes multiplexing and high integration in the non-MIMO (multi-in multi-out) multimode transmission system. A sufficient mode crosstalk of -20 dB was obtained by selecting suitable parameters of the spacing between the connecting positions of each arrayed waveguide Di, the radius slab waveguide R0 and lateral V-parameter.. |
| 9. |
Yu Han, Zanhui Chen, Leiyun Wang, Wenying Li, Haisong Jiang, Kiichi Hamamoto, Asymmetric-ration optical power couplers based on nano-pixel structure, OSA CONTINUUM, 10.1364/OSAC.412933, 4, 2, 556-568, 2021.02, An optical power coupler is one of the most well-used components in integrated photonics. Although couplers with an output power ratio 1:1 have been widely studied in the past, constructing asymmetric-ration optical power couplers is still an issue that is difficult to be addressed by using traditional Y-branch waveguides. Artificial intelligence (AI) assisted design is an effective technique for realizing complex optical structures. In this work, we have designed asymmetric-ration optical power couplers by using AI assisted design. TWo couplers with the targeted splitting power ratio as 1:9 and 1:99 have been designed, respectively. In the AI assisted design, the coupler area was divided into discrete nano-pixels in the shape of circular holes with the same dimension. The AI controlled each pixel to be occupied by waveguide or air and trialed the occupation of each pixel one by one. In a 3.4 x 3.2 mu m(2) area, it took 1452 trials to obtain one optimized coupler. As a result, a splitting power ratio of 1:9.007 and 1:99.004 for the two couplers has been confirmed by using the finite-difference time-domain method. In addition, the waveguide configuration was further modified as the excess loss of the AI-designed coupler was a bit high, more than 3.50dB. The way to reduce the loss is as follows: 1) positioning optimization of the output waveguide to avoid light scattering at the boundary between the coupler and the output waveguide, and 2) widening the output waveguide width to avoid insufficient light coupling. As a result, a scattering loss reduction of 1.7 dB by position optimization, and a coupling loss reduction of 1.6dB by width widening were confirmed. The achieved design also exhibited a wide operation wavelength ranging from 1500-1600 nm in addition to sufficient fabrication tolerance of +/- 10nm (+/- 11%). (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement. |
| 10. |
JIANG Haisong, HINOKUMA Yasuhiro, GHOSH Sampad, KUWAHATA Ryota, HAMAMOTO kiichi, Concept Demonstration of 3D Waveguides Shuffle Converter for Multi-Core Fiber/Single-Mode Fiber Fan-in Fan-out Configuration Toward Over 1,000 Port Count, IEICE Transactions on Electronics, 10.1587/transele.2020ecs6002, E104.C, 1, 34-36, 2021.01, A novel shuffle converter by using 3D waveguide of MCF (multi-core fiber)/SMF (single mode fiber) ribbon fan-in fan-out configuration towards over 1,000 port count optical matrix switch has been proposed. The shuffle converter enables to avoid waveguide crossing section in the optical matrix switch configuration, and the principle device showed sufficient crosstalk of less than -54.2 dB, and insertion loss of 2.1 dB successfully.. |
| 11. |
Zan Hui Chen, Wenying Li, Yu Han, Leiyun Wang, Haisong Jiang and Kiichi Hamamoto,, Vertical field enhancement of spot size converter with nano-pixels waveguide and window structure, Optics Express, https://doi.org/10.1364/OE.412911, 29, 2, 2757-2768, 2021.01. |
| 12. |
Zan Hui Chen, Wenying Li, Yu Han, Leiyun Wang, Haisong Jiang, Kiichi Hamamoto, Vertical field enhancement of a spot-size converter using a nanopixel waveguide and window structure, OPTICS EXPRESS, 10.1364/OE.412911, 29, 2, 2757-2768, 2021.01, Spot-size converter (SSC) is an essential building block for integrated photonic circuits applied as a mode transformer between optical components. One typical issue for SSC is the difficulty of broadening the vertical field profile. Herein, we propose a nanopixel SSC (1 x 2 mu m(2)) with changing hole size and density. Unlike a typical SSC, this configuration controls both the lateral and vertical field profiles relatively easily by enhancing the nanopixel density. A vertical field expansion of 1.21 mu m was obtained by enhancing the nanopixel density. In addition, we designed the optical field in the lateral direction using deep neural network (DNINO-based learning to realize a perfect circular spot for high coupling efficiency that reached -3 dB at lambda(0) = 1.572 gm when the optical field aspect ratio was adjusted to 1 after training for 200 epochs. Furthermore, the vertical expansion was increased from 1.21 to 4.9 mu m and the coupling efficiency from -3 to -0.41 dB by combining it a silicon dioxide window structure (5 x 15 x 10 mu m(3)). The 1-dB operating bandwidth of the designed SSC structure is 100 nm (1.5-1.6 mu m), while fabrication tolerance of the nanopixels and window structure length for the designed SSC structure are +/- 15 nm and +/- 250 nm when the coupling efficiency drops by 1 dB. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement. |
| 13. |
Wenying Li, Yu Han, Zanhui Chen, Leiyun Wang, Haisong Jiang, and Kiichi Hamamoto, Amplifier-assisted waveguide sensing toward breath-gas analysis, Engineering Sciences Reports, Kyushu University, 42, 1, 19-26, 2020.09. |
| 14. |
HAMAMOTO Kiichi, JIANG Haisong, Erratum: Mode Selective Active Multimode Interferometer Laser Diode — Mode Selection Principle, and High Speed Modulation — [IEICE Transactions on Electronics Vol.E102.C (2019) , No.4 pp.364-370], IEICE Transactions on Electronics, 10.1587/transele.2020ece0001, E103.C, 8, 381_e1-381_e1, 2020.08. |
| 15. |
Yu Han, Wenying Li, Zanhui Chen, Haisong Jiang, Kiichi Hamamoto, Fabrication and analysis of low-loss silicon high-mesa waveguides, APPLIED OPTICS, 10.1364/AO.391604, 59, 16, 4964-4969, 2020.06, Breath sensing is an effective tool for health monitoring. Previously, high-mesa waveguide structures have been proposed by our group for realizing a compact breath-sensing photonic circuit. By using the doped SiO2 as the waveguide core, 50% concentration CO2 has been detected. One issue of preventing parts per million (ppm)-order detection is the low portion of evanescent light (Gamma(air) = 2.2%) in the doped SiO2 waveguides. In order to realize low propagation loss a and high simultaneously, thin silicon (Si) waveguides with a Gamma(air) as high as 37.6% have been proposed and fabricated in this work. A thermal oxidation technique was applied to further reduce a, so that a was decreased from 1.45 to 0.84 and 0.29 to 0.2 dB/cm for the 0.5 and 3-mu m-wide waveguide, respectively. According to our analysis, the significantly decreased alpha is attributed to recovering the damaged Si core and smoothing the waveguide sidewalls. The high Gamma(air) air and effective loss reduction show a promising potential of applying Si high-mesa waveguides to realize ppm-order sensing. (C) 2020 Optical Society of America. |
| 16. |
Li Wenying, Han Yu, Chen Zanhui, Jiang Haisong, Hamamoto Kiichi, Compact Breath Sensing using Amplifier Assisted CRDS (Cavity Ring-down Spectroscopy), 10.15017/2552953, 5, 107-108, 2019.10. |
| 17. |
Chen Zan Hui, Jiang Haisong, Hamamoto Kiichi, Compact and Highly Sensitive Methane Sensor Based on Two Tangent Air Hole Structure, 10.15017/2552951, 5, 103-104, 2019.10. |
| 18. |
Murakami Shingo, Hong Bingzhou, Jiang Haisong, Hamamoto Kiichi, Observation of 60 GHz and 20 GHz Multiple Photon-Photon Resonances Using Active Multimode Interferometer Laser Diodes, 2019 24TH MICROOPTICS CONFERENCE (MOC), 10.15017/2552954, 5, 109-110, 2019.10, We have designed and fabricated 1 x N active multimode interferometer laser diodes to achieve two photon-photon resonances (PPRs). Very high frequency of 60 GHz in addition to 20 GHz PPR peaks were confirmed.. |
| 19. |
Ogawa Satoshi, Jiang Haisong, Hamamoto Kiichi, Proposal of 1×N Optical Mode Switch Based on Spatial Single Dimensional Mode, 2019 24TH OPTOELECTRONICS AND COMMUNICATIONS CONFERENCE (OECC) AND 2019 INTERNATIONAL CONFERENCE ON PHOTONICS IN SWITCHING AND COMPUTING (PSC), 10.15017/2552952, 5, 105-106, 2019.10, 1xN optical mode switch is newly proposed in this paper. Simulated results show all the switching under low excess loss (1.6 dB) due to the precise eigen-mode realization.. |
| 20. |
Propagation Mode Retention at Fiber Bending Region Using Strongly Coupled Multi-Core Fiber. |
| 21. |
Significant Propagation Loss Reduction on Silicon High-Mesa Waveguides Using Thermal Oxidation Technique
We have exploited thermal oxidation technique to silicon high-mesa waveguides for sensing-application. Significant propagation loss reduction from 1.45 to 0.84 dB/cm at a waveguide width of 500 nm has been achieved by the technique successfully.. |
| 22. |
Satoshi Ogawa, Ahmad Syahrin Idris, Yu Han, Haisong Jiang, Kiichi Hamamoto, Surface improvement investigation of sol-gel SiO2 cladding for waveguide device passivation, JAPANESE JOURNAL OF APPLIED PHYSICS, 10.7567/1347-4065/ab27b2, 58, 2019.08, The sol-gel method is a well-known process for SiO2 formation on top of a semiconductor-based waveguide. This method does not require expensive equipment or SiH4 gas. However, it may result in difficulty with wet-etching, which prevents proper current injection into the semiconductor layer. We have investigated the surface condition of sol-gel SiO2 on top of Si, and have confirmed that the main causes of the antietching property might be due to the formation of a polymer layer after the curing process. To improve the surface condition, plasma ashing, in addition to 700 degrees C curing, is proposed. Regular wet etching of SiO2 layer on Si with a ratio of 1800 nm min(-1) has been successfully confirmed. (C) 2019 The Japan Society of Applied Physics. |
| 23. |
Bingzhou Hong, Tomotaka Mori, Shingo Murakami, Haisong Jiang, Kiichi Hamamoto, A space mode selective light source with over 40 GHz direct modulation bandwidth, JAPANESE JOURNAL OF APPLIED PHYSICS, 10.7567/1347-4065/ab1fd7, 58, 2019.08, A high-speed mode selective light source with over 40 GHz direct modulation bandwidth on both 0th and 1st order modes was demonstrated on an active multimode interferometer laser diode (active-MMI LD). By introducing multiple photon-photon resonances (PPR), the bandwidth of small signal frequency response is extremely extended. As the advantage of the active-MMI, the designed PPR frequencies are stable and do not change as the cleaving condition changes. In this work, 1 x 3 asymmetric active-MMI LD was fabricated to introduce multiple PPRs. Over 40 GHz direct modulation bandwidth has been confirmed experimentally on both 0th and 1st order modes. (C) 2019 The Japan Society of Applied Physics. |
| 24. |
Mahmoud Nasef, Fujimoto Kantaro, Haisong Jiang, Kiichi Hamamoto, Propagation Mode Retention Using Strongly Coupled Multi-Core Fiber, IEICE Proceeding Series, 10.34385/proc.31.p-15, 31, P-15-83, 2019.05, "Data center traffic is already estimated to become 20 ZB by the year 2021 about twice as much as in 2018 [1]. MDM (mode division multiplexing) can expand transmission capacity within data center [2]; therefore, we propose to introduce an optical network system utilizing MDM into data centers [3]. It has; however, a problem of mode crosstalk in the fiber that prevents proper preservation of individual mode transmission. One main cause of this crosstalk has been mode excitation phenomenon at the bending region of the fiber [4]. In this paper, we study and demonstrate strongly coupled MCF to verify the mode retaining capability. We simulated and estimated the transmittance of input mode by using BPM (beam propagation method) simulation and verified the results by an experiment setup involving 4-cores strongly coupled MCF. As a result, we verified the mode retention characteristics of 5dB at 80mm bending radius, compared to regular multi-mode fiber.". |
| 25. |
Haisong Jiang, Mahmoud Nasef, Fujimoto Kantaro, Kiichi Hamamoto, Spatial Single Dimensional Mode De-multiplexer Based on Rowland Circle Waveguide, IEICE Proceeding Series, 10.34385/proc.31.p-17, 31, P-17, 2019.05, Several mode de-multiplexers base on LP mode (Linearly Polarized) have been proposed and demonstrated [1-3], however, LP mode based multiplexing, have required multi-in multi-out (MIMO) processing due to its difficulty of mode de-multiplexing caused by the mode degeneration and the mode crosstalk. In order to resolve this problem, spatial multiplexing transmission using a single dimensional spatial mode has been proposed [4-5]. We are studying a phase control type de-multiplexer using Rowland circle waveguide to de-multiplex singledimensional spatial mode [6]. In this work, we investigated the light focusing function of the Rowland circle waveguide for single dimensional spatial mode. The simulated result shows the possibility of de-multiplexing single dimensional spatial mode with this configuration.. |
| 26. |
Kiichi Hamamoto, Haisong Jiang, Mode selective active multimode interferometer laser diode - Mode selection principle, and high speed modulation, IEICE Transactions on Electronics, 10.1587/transele.2018ODI0003, E102C, 4, 364-370, 2019.04, We have proposed and demonstrated a mode selective active-MMI (multimode interferometer) laser diode as a mode selective light source so far. This laser diode features; 1) lasing at a selected space mode, and 2) high modulation bandwidth. Based on these, it is expected to enable high speed interconnection into future personal and mobile devices. In this paper, we explain the mode selection, and the high speed modulation principles. Then, we present our recent results concerning high speed frequency response of the fundamental and first order space modes.. |
| 27. |
Kiichi Hamamoto, Haisong Jiang, Mode Selective Active Multimode Interferometer Laser Diode -Mode Selection Principle, and High Speed Modulation-, IEICE TRANSACTIONS ON ELECTRONICS, 10.1587/transele.2018ODI0003, E102C, 4, 364-370, 2019.04, We have proposed and demonstrated a mode selective active-MMI (multimode interferometer) laser diode as a mode selective light source so far. This laser diode features; 1) lasing at a selected space mode, and 2) high modulation bandwidth. Based on these, it is expected to enable high speed interconnection into future personal and mobile devices. In this paper, we explain the mode selection, and the high speed modulation principles. Then, we present our recent results concerning high speed frequency response of the fundamental and first order space modes.. |
| 28. |
CHEN ZANHUI, Li Wenying, Han Yu, Jiang Haisong, Hamamoto Kiichi, Proposal of Two Tangent Hole Structure for Higher Sensitivity Gas Sensor, JSAP Annual Meetings Extended Abstracts, 10.11470/jsapmeeting.2019.1.0_830, 2019.1, 830-830, 2019.02, One-dimensional photonic crystal (1D PhC) cavities are used as ultrasensitive gas sensors due to their high sensitivity to changes in the surrounding environment. One of the issues for typical 1D PhC-based sensors is that the confined optical field does not fully overlap with analytes, which therefore leads to low sensitivity. Herein, we propose and numerically investigate a photonic crystal cavity by introducing a two tangent air hole array to improve the gas refractive index sensitivity. We also investigate the spectral feature of the proposed photonic crystal cavity for varying structure parameters and methane gas concentration. In addition, the coupling efficiency of the waveguide and the influence of the temperature on the proposed structure for sensing applications are analyzed. Theoretical analysis reveals that the proposed two tangent hole structure simultaneously achieves a high sensitivity (353 nm/RIU) and figure of merit (FOM = 1.2 x 10(4)) compared to those observed in previous studies. (C) 2019 The Japan Society of Applied Physics. |
| 29. |
Bingzhou Hong, Tomotaka Mori, Shingo Murakami, Haisong Jiang, Kiichi Hamamoto, A space mode selective light source with over 40 GHz direct modulation bandwidth, Japanese Journal of Applied Physics, 10.7567/1347-4065/ab1fd7, 58, SJ, 2019.01, A high-speed mode selective light source with over 40 GHz direct modulation bandwidth on both 0th and 1st order modes was demonstrated on an active multimode interferometer laser diode (active-MMI LD). By introducing multiple photon-photon resonances (PPR), the bandwidth of small signal frequency response is extremely extended. As the advantage of the active-MMI, the designed PPR frequencies are stable and do not change as the cleaving condition changes. In this work, 1 × 3 asymmetric active-MMI LD was fabricated to introduce multiple PPRs. Over 40 GHz direct modulation bandwidth has been confirmed experimentally on both 0th and 1st order modes.. |
| 30. |
Wenying Li, Yu Han, Zanhui Chen, Haisong Jiang, Kiichi Hamamoto, Amplifier-assisted CRDS (cavity ring-down spectroscopy) toward compact breath sensing, Japanese Journal of Applied Physics, 10.7567/1347-4065/ab1e3d, 58, SJ, 2019.01, A cavity-ring-down spectroscopy (CRDS) system utilizing waveguide for breath sensing realizes several meter optical path integration that has possibility for ppm-order gas sensing within a compact area. We have proposed an optical amplifier assisted gas sensing system scheme to compensate waveguide propagation loss that may prevent ppm-order gas detection. The amplifier in a CRDS system, however, may result in self-lasing at specific wavelength in case of high pumping condition. Once self-lasing happens, signal light loose its gain from amplifier. The amplifier spontaneous emission that generated by an erbium-doped fiber amplifier affects the background noise level of cavity ring-down waveforms. In this work, we propose the scheme of polarization direction control so as to suspend the self-lasing, and the scheme of additional loss as to suppress ASE power. As a result, we confirmed the suppression of light intensity at a self-lasing wavelength below -50 dBm and the gain improvement of 24 dB at signal.. |
| 31. |
Zan Hui Chen, Wenying Li, Yu Han, Haisong Jiang, Kiichi Hamamoto, Proposal of two tangent air hole structure for higher sensitivity gas sensor, Japanese Journal of Applied Physics, 10.7567/1347-4065/ab26ab, 58, SJ, 2019.01, One-dimensional photonic crystal (1D PhC) cavities are used as ultrasensitive gas sensors due to their high sensitivity to changes in the surrounding environment. One of the issues for typical 1D PhC-based sensors is that the confined optical field does not fully overlap with analytes, which therefore leads to low sensitivity. Herein, we propose and numerically investigate a photonic crystal cavity by introducing a two tangent air hole array to improve the gas refractive index sensitivity. We also investigate the spectral feature of the proposed photonic crystal cavity for varying structure parameters and methane gas concentration. In addition, the coupling efficiency of the waveguide and the influence of the temperature on the proposed structure for sensing applications are analyzed. Theoretical analysis reveals that the proposed two tangent hole structure simultaneously achieves a high sensitivity (353 nm/RIU) and figure of merit (FOM = 1.2 × 104) compared to those observed in previous studies.. |
| 32. |
Ahmad Syahrin Idris, Haisong Jiang, Kiichi Hamamoto, Multi-layer stacking scheme of sol-gel based SiO
2
towards thicker (>0.8 µm) cladding layers for optical waveguides, IEICE Electronics Express, 10.1587/elex.15.20180783, 15, 19, 2018.10, A multi-layer stacking scheme using a sol-gel SiO
2
fabrication technique was developed towards stacking thick layers of >0.8 µm for cladding and passivation layers of optical waveguides. The multi-layer stacking scheme, which improves the intrinsic stress problem especially in case of thick layer stacking, enables a >0.8 µm sol-gel SiO
2
thickness without cracking and peeling issues. As a result, thick layer of 3.5 µm with high surface resistivity of >6.6 × 10
13
Ω/m was obtained. Furthermore, a-Si/SiO
2
waveguide (cladding thickness: 1.9 µm) was realized to confirm the fundamental potential as a cladding layer.. |
| 33. |
Nasef Mahmoud, Jiang Haisong, Hamamoto Kiichi, Research on Mode Multiplexer / Demultiplexer by Using Optical Waveguides for MDM Transmission System, 10.15017/1961297, 4, 106-107, 2018.10. |
| 34. |
Preliminary Research on Spatial Single Dimensional Modes Demultiplexer by Adjusting Phase Wavefronts. |
| 35. |
Amplifier Assisted CRDS (Cavity Ring-down Spectroscopy) toward Compact Breath Sensing
A cavity-ring-down spectroscopy (CRDS) system utilizing waveguide for breath sensing realizes several meter optical path integration that has possibility for ppm-order gas sensing within a compact area. We have proposed an optical amplifier assisted gas sensing system scheme to compensate waveguide propagation loss that may prevent ppm-order gas detection. The amplifier in a CRDS system, however, may result in selflasing at specific wavelength in case of high pumping condition. Once self-lasing happens, signal light loose its gain from amplifier. The amplifier spontaneous emission that generated by an erbium-doped fiber amplifier affects the background noise level of cavity ring-down waveforms. In this work, we propose the scheme of polarization direction control so as to suspend the self-lasing, and the scheme of additional loss as to suppress ASE power. As a result, we confirmed the suppression of light intensity at a self-lasing wavelength below -50 dBm and the gain improvement of 24 dB at signal. (C) 2019 The Japan Society of Applied Physics. |
| 36. |
B. Hong, T. Kitano, T. Mori, Haisong Jiang, K. Hamamoto, Bandwidth enhancement scheme demonstration on direct modulation active-MMI laser diode using multiple photon photon resonance, Applied Physics Letters, 10.1063/1.5005070, 111, 22, 2017.11, By introducing properly designed multiple photo photon resonances (PPRs) on an active-Multimode Interferometer Laser Diode, the confirmed direct modulation bandwidth was enhanced from less than 5 GHz to at least 34 GHz. Multiple oscillating cavities that have slightly different free space ranges (FSRs) are integrated within a single device. The overlap between such FSRs contributes to multiple wavelength differences that are directly related to the PPR frequencies. Evaluated PPR frequencies from experimental data match with designed frequencies. The potential of the 100 GHz level bandwidth of the device has been proved.. |
| 37. |
Bingzhou Hong, Takuya Kitano, Haisong Jiang, Akio Tajima, Kiichi Hamamoto, First Demonstration of Mode Selective Active Multimode Interferometer Laser Diode, IEICE TRANSACTIONS ON ELECTRONICS, 10.1587/transele.E100.C.775, E100C, 10, 775-781, 2017.10, We newly propose the first lateral mode selective active multimode interferometer laser diode. The design principle is to arrange identical propagation path of different lateral mode. Thanks to multimode waveguide structure, 0th mode and 1st order mode has individual propagation path within one device. Individual lasing of fundamental mode as well as first mode was confirmed successfully.. |
| 38. |
Haisong Jiang, Ryan Imansyah, Luke Himbele, Shota Oe, Kiichi Hamamoto, Fast Mode-Switching (60 ns) by Using A 2 x 2 Silicon Optical Mode Switch, IEICE TRANSACTIONS ON ELECTRONICS, 10.1587/transele.E100.C.782, E100C, 10, 782-788, 2017.10, We present dynamic mode switching characteristic by using a 2 x 2 optical mode switch based on silicon waveguide. The configuration of optical mode switch is similar to MZI where the width of input and output ports are designed to permit the combining of the fundamental mode and the first order mode. We designed the symmetrical arms with phase shifter based on p-i-n structure in one arm to generate a p-phase difference between each arm. As a result, mode switching with the injection current of 60mA (5.7 V) was successfully achieved with the mode crosstalk of -10 dB at lambda = 1550 nm. A minimum of less than 60 ns and 40 ns mode switching time for the fundamental mode to first order mode and first order mode to fundamental mode, was achieved respectively in this time.. |
| 39. |
Ghosh Sampad, Idris Ahmad Syahrin, Jiang Haisong, Hamamoto Kiichi, Realization of a Stacked Waveguide using Higher Refractive Index Material with SiO_2 as Cladding, 10.15017/1906119, 3, 19-20, 2017.10. |
| 40. |
Ahmad Syahrin Idris, Sampad Ghosh, Haisong Jiang, Kiichi Hamamoto, A multi-layer stacked all sol-gel fabrication technique for vertical coupled waveguide, Evergreen, 4, 2-3, 12-17, 2017.09, A multi-layer vertically stacked all sol-gel fabrication technique on bulk silicon is proposed to realize vertical coupling from planar waveguides to 3-dimensional structures. The all sol-gel fabrication technique realizes the capability to stack ZnO sol-gel core layer and SiO2 sol-gel cladding and core separation layers. A major issue with sol-gel based fabrication is the appearance of cracks on the sol-gel layer, and these were improved by a slow cooling process of 1°C/min after 500°C temperature annealing in addition to a SiO2 surface cleaning using photoresist remover. As a result, a multi-layer vertically stacked structure with a ZnO core layer thickness of 300 nm and SiO2 cladding/core separation layer thickness of 1.5 μm was successfully fabricated on bulk Si.. |
| 41. |
Idris Ahmad Syahrin, Ghosh Sampad, Jiang Haisong, Hamamoto Kiichi, Multi-Layer All Sol-Gel Fabrication Technique on Bulk Silicon toward Vertical Coupler, JSAP Annual Meetings Extended Abstracts, 10.11470/jsapmeeting.2017.2.0_979, 2017.2, 979-979, 2017.08. |
| 42. |
A. S. Idris, Haisong Jiang, Kiichi Hamamoto, Accurate dry etching technique for germanium waveguide by using CHF3 based inductively coupled plasma, Electronics Letters, 10.1049/el.2016.2846, 52, 22, 1868-1869, 2016.10, A CHF3 inductively coupled plasma (ICP) based dry etching method is proposed for accurate etching of Ge waveguides. CHF3 ICP based dry etching produces excellent anisotropy along with good selectivity with regards to regular polymeric photoresist, which leads to the elimination of under-cut. As a result, an almost vertical sidewall angle of 85° with an etching rate of 190 nm/min was realised with a relatively high selectivity ratio of 5:1 against regular photoresist.. |
| 43. |
Hokazono Hirohito, Jiang Haisong, Hamamoto Kiichi, Optical field profile evaluation on silica high-mesa waveguide for infrared absorption sensing, 10.15017/1812436, 38, 1, 1-6, 2016.09. |
| 44. |
Takuya Kitano, Mohammad Nasir Uddin, Bingzhou Hong, Akio Tajima, Haisong Jiang, Kiichi Hamamoto, Demonstration of photon-photon resonance peak enhancement by waveguide configuration modification on active multimode interferometer laser diode, JAPANESE JOURNAL OF APPLIED PHYSICS, 10.7567/JJAP.55.08RD04, 55, 8, 2016.08, The recent rapid growth of data traffic is leading to high-speed communication for local areas, such as the fiber-to-the-home service. A semiconductor laser is used for such a purpose; however, there is the difficulty that an even higher frequency response occurs in only carrier-photon resonance. For this reason, it is effective to use a second resonance, such as a photon-photon resonance (PPR), for enhancing the frequency response, and the active multimode interferometer laser diode (active-MMI LD) is one of the candidates for achieving a high PPR frequency. In order to obtain an even higher PPR frequency, we have investigated the control scheme of enhancing PPR. In this work, we compared two types of active-MMI waveguide structures to confirm the scheme. As a result, a 3.8 GHz enhancement of the PPR peak, resulting in a 3 dB lower frequency response of 17 GHz, has been successfully achieved by waveguide geometry modification. (C) 2016 The Japan Society of Applied Physics.. |
| 45. |
Ryan Imansyah, Tatsushi Tanaka, Luke Himbele, Haisong Jiang, Kiichi Hamamoto, Electrically controlled optical-mode switch for fundamental mode and first order mode, Japanese Journal of Applied Physics, Part 1: Regular Papers & Short Notes, 10.7567/JJAP.55.08RB06, 55, 8, 2016.08, We have proposed an optical mode switch, the principle of which is based on the partial phase shift of injected light; therefore, one important issue is to clarify the proper design criteria for the mode combiner section. We focused on the bending radius of the S-bend waveguide issue that is connected to the multi mode waveguide in the Y-junction section that acts as mode combiner. Long radius leads to undesired mode coupling before the Y-junction section, whereas a short radius causes radiation loss. Thus, we simulated this mode combiner by the beam-propagation method to obtain the proper radius. In addition, we used a trench pin structure to simplify the fabrication process into a single-step dry-etching process. As a result, we successfully fabricated an optical-mode switch with the bending radius R = 610 m. It showed the successful electrical mode switching and the achieved mode crosstalk was approximately %10 dB for 1550nm wavelength with the injection current of 60mA (5.7 V).. |
| 46. |
Ryan Imansyah, Tatsushi Tanaka, Luke Himbele, Haisong Jiang, and Kiichi Hamamoto, Mode Crosstalk Evaluation on Optical Mode Switch by Using MMI Mode Filter, IEICE Transaction on Electonics, E99-C, 7月, 825-829, 2016.07. |
| 47. |
Ryan Imansyah, Tatsushi Tanaka, Luke Himbele, Haisong Jiang, Kiichi Hamamoto, Electrically controlled optical-mode switch for fundamental mode and first order mode, Japanese Journal of Applied Physics, 10.7567/jjap.55.08rb06, 10.1587/transele.e100.c.782_references_DOI_GzWIMJJFo1bI9Ublmu1A7kijR5N, 55, 8S3, 08RB06, 2016.07. |
| 48. |
Ryan Imansyah, Tatsushi Tanaka, Luke Himbele, Haisong Jiang, Kiichi Hamamoto, Mode Crosstalk Evaluation Method by Using MMI Mode Filter for Optical Mode Switch, IEICE TRANSACTIONS ON ELECTRONICS, 10.1587/transele.E99.C.825, E99C, 7, 825-829, 2016.07, We have proposed and demonstrated the principle of optical mode switch. However, the crosstalk between modes has not yet reported due to the difficulty of mode recognition and distinction. To accomplish this mode crosstalk evaluation, we integrated multimode interference (MMI) mode filter with the optical mode switch in this work. As a result, for the both TE and TM modes, the crosstalk of approximately - 10 dB has been evaluated experimentally.. |
| 49. |
Idris Ahmad Syahrin, Jiang Haisong, Hamamoto Kiichi, C-3-42 Dry Etching of Ge by Using CHF_3 Inductively Coupled Plasma for Ge Waveguides, Proceedings of the IEICE General Conference, 2016, 1, 180, 2016.03. |
| 50. |
Yutaka Chaen, Kazuhiro Kazuhiro, Haisong Jiang, Kiichi Hamamoto, Low wavelength dependency design for MMI (multi-mode interference) mode converter, IEICE ELECTRONICS EXPRESS, 10.1587/elex.12.20150727, 12, 20, 2015.10. |
| 51. |
Kiichi Hamamoto, Haisong Jiang, Active MMI devices: concept, proof, and recent progress, JOURNAL OF PHYSICS D-APPLIED PHYSICS, 10.1088/0022-3727/48/38/383001, 48, 38, 2015.09. |
| 52. |
Hirohito Hokazono, Wenying Li, Syota Enami, Haisong Jiang, Kiichi Hamamoto, Gas sensing demonstration by using silica high-mesa waveguide with amplified cavity ring down spectroscopy technique, IEICE ELECTRONICS EXPRESS, 10.1587/elex.12.20150574, 12, 15, 2015.08. |
| 53. |
Kiichi Hamamoto, Haisong Jiang, Active MMI devices: concept, proof, and recent progress, Journal of Physics D: Applied Physics, 10.1088/0022-3727/48/38/383001, 10.7567/1347-4065/ab090f_references_DOI_RPRj6MFCJEfiJM5RxJ2vQUve0qB, 10.1587/transele.e100.c.775_references_DOI_RPRj6MFCJEfiJM5RxJ2vQUve0qB, 48, 38, 383001, 2015.08. |
| 54. |
Imansyah Ryan, Himbele Luke, Jiang Haisong, Hamamoto Kiichi, C-3-17 Electrically Controlled Mode Switching Using Trench Structure, Proceedings of the Society Conference of IEICE, 2015, 1, 91, 2015.08. |
| 55. |
Yasuhiro Hinokuma, Yutaka Chaen, Haisong Jiang, Takuma Hagio, Seiki Nakamura, Akio Tajima, Kiichi Hamamoto, CW Single-Wavelength Emission by Using Novel Asymmetric Configuration for Active Multi-Mode Interferometer Laser Diodes, IEICE Electronics Express (ELEX), 9, 18, 1448-1453, 2012.09, We report CW single-wavelength emission at RT from non-grating active multi-mode interferometer laser diodes (MMI LDs) by using an asymmetric configuration. Fabricated devices showed side-mode suppression ratio (SMSR) of 31 dB (λ=1.56μm). We also present the modulation characteristics of this novel device at 1.25 Gbps for a 27−1 pseudorandom binary sequence.. |
| 56. |
Haisong Jiang, Yutaka Chaen, Takuma Hagio, Kazuisao Tsuruda, Makoto Jizodo, Shinji Matsuo, Jing Xu, Christophe Peucheret, Kiichi Hamamoto, All-optical flip-flop operation based on asymmetric active-multimode interferometer bi-stable laser diodes, OPTICS EXPRESS, 10.1364/OE.19.00B119, 19, 26, B119-B124, 2011.12, We demonstrate fast and low energy all optical flip-flop devices based on asymmetric active-multimode interferometer using high-mesa waveguide structure. The implemented devices showed high speed all-optical flip-flop operation with 25ps long pulses. The rising and falling times of the output signal were 121 ps and 25 ps, respectively. The required set and reset pulse energies were only 7.1 fJ and 3.4 fJ, respectively.. |
| 57. |
Haisong Jiang, Hany Ayad Bastawrous, Takuma Hagio, Shinji Matsuo, Kiichi Hamamoto, Low Hysteresis Threshold Current (39 mA) Active Multimode-Interferometer (MMI) Bistable Laser Diodes Using Lateral-Modes Bistability, IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS, 10.1109/JSTQE.2011.2156386, 17, 5, 1258-1263, 2011.09, We demonstrate low hysteresis threshold current (39 mA) bistable laser diodes (BLDs), with maintaining sufficient hysteresis window(7 mA, 18% of the hysteresis threshold), in active multimode-interferometer (MMI) using lateral-modes bistability. The sufficient cross-gain saturation effect, due to the lateral-modes bistability principle, enables wide hysteresis window. By using this principle, we could design the active-MMI BLDs with relatively short saturable-absorber length that has been one of the main causes of high hysteresis threshold current. In the actual design, we reduce the saturable-absorber region length to 25 mu m, and thus, we could achieve a low hysteresis current of 39 mA in the active MMI BLDs with maintaining sufficient hysteresis window for the first time.. |
| 58. |
Haisong Jiang, Hany Ayad Bastawrous, Hirotaka Saikaku, Yuichiro Tahara, Shinji Matsuo, Kiichi Hamamoto, Optical Bit-Memory Element Based on Bi-Stability between Different Lateral Modes Using Novel Active Multi-Mode-Interferometer (MMI) for Random Access Memory (RAM) Application, Engineering Science Reports, Kyushu University, 31, 1, 1-6, 2009.06, A novel principle of active multi-mode-interferometer (MMI) bi-stable laser diode (BLD), utilizing different lateral modes, has been proposed and demonstrated for optical random access memory (RAM) application. The two different propagation modes realize two different identical paths in a single active MMI cavity simultaneously, with sharing exactly same port at one facet side. This novel concept contributes to realize relatively large cross-gain saturation region between the two identical paths, which result in stable bi-stability even in a relatively compact device size. Implemented devices showed relatively low operation current of 100mA and sufficient hysteresis window of 8mA with the cavity length of only 550µm. High optical ON/OFF ratio of more than 15dB was also confirmed successfully.. |
