session 1: photonic integration and optical interconnect...energy-efficient silicon photonic...

The 9th International Conference on Information Optics and PhotonicsSession 1: Photonic Integration and Optical Interconnect

- 5 -

Sess

ion

1

Session 1: Photonic Integration and Optical Interconnect

18th JulyChair: Daoxin Dai, Zhejiang University, China

14:00-14:45Photonic Integrated Devices with Nanostructures (Keynote) Yidong HuangTsinghua University, China

- 7 -

14:45-15:15Energy-Efficient Silicon Photonic Transmitters for Pulse-Amplitude Modulation (Invited) Wei ShiCenter for optics, photonics, and lasers (COPL), Laval University, Canada

- 8 -

15:15-15:45Engineering Wavefront for Tailoring Accelerating Beams Based on Integrated Photonic Approaches (Invited) Yujie ChenSun Yat-sen University, China

- 9 -

15:45-16:00 Coffee BreakChair: Yidong Huang, Tsinghua University, China

16:00-16:30Silicon Microring Resonators for Optical Filtering and Switching (Invited) Daoxin DaiZhejiang University, China

- 10 -

16:30-17:00Photonic Integrated Devices on Silicon Platform for Chip-Scale Optical Interconnects and Processing (Invited) Jian WangHuazhong University of Science and Technology, China

- 11 -

17:00-17:30Electro-Optic Modulation and Thermo-Optic Tuning Based on Silicon-Graphene Hybrid Structure (Invited) Ciyuan QiuShanghai Jiao Tong University, China

- 12 -

18:00-19:00 Dinner Time

19th JulyChair: Baile Zhang, Nanyang Technological University, Singapore

09:00-09:30Silicon Optical Modulators with Advanced Modulation Formats (Invited) Lin YangState Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, CAS, Beijing, China

- 13 -

09:30-10:00Monolithic Integration of III-V Quantum Dot Lasers on Silicon for Silicon Photonics (Invited) Siming ChenUniversity College London, UK

- 14 -

10:00-10:30Physics-Enabled Design and Innovation in Silicon Photonics: From Novel Devices to High-Density Waveguides Integration (Invited) Wei JiangNanjing University, China

- 15 -

10:30-10:45

Relative Intensity Noise of An InAs/GaAs Quantum Dot Laser Epitaxially Grown on Germanium (Oral) Cheng Zhou1, Yueguang Zhou2, Chunfang Cao3, Jiangbing Du1, Qian Gong3, Cheng Wang2 1 Shanghai Jiao Tong University, China; 2 ShanghaiTech University, China; 3 Shanghai Institute of Microsystem and Information Technology, CAS, China

- 19 -

10:45-11:00 Coffee BreakChair: Lin Yang, State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, CAS, Beijing, China

11:00-11:30Surface-Wave Photonic Crystals (Invited) Baile ZhangNanyang Technological University, Singapore

- 16 -

11:30-11:45Measure and Correct the Orbital Angular Momentum Spectra of Light Beams (Oral) Peng Zhao, Xue Feng, Yidong Huang Tsinghua University, China

- 19 -

12:15-14:00 Lunch Time

Zhiping (James) Zhou, Peking University, ChinaYidong Huang, Tsinghua University, ChinaSiyuan Yu, Sun Yat-sen University, China

Session Chairs:

Location: B515, 5F, Main Building, Harbin Institute of Technology No.2 Campus

The 9th International Conference on Information Optics and PhotonicsSession 1: Photonic Integration and Optical Interconnect

- 6 -

Session 1

19th JulyChair: Wei Jiang, Nanjing University, China

14:00-14:30Integrated Devices for Optical Vortices (Invited) Xue FengTsinghua University, China

- 17 -

14:30-15:00China Silicon Photonics Platform in A Multi Project Wafer Service (Invited) Junbo FengChina Electronics Technology Group Corporation 38th Research Institute, China

- 18 -

15:30-16:00 Coffee Break15:30-17:30 Poster18:00-20:00 Banquet

The 9th International Conference on Information Optics and PhotonicsSession 1——Invited Talks

Note

- 7 -

Sess

ion

1

Photonic Integrated Devices with Nanostructures

ABSTRACT

BIOGRAPHYYidong Huang was born in Beijing, China. She received the B.S.

and Ph.D. degrees in optoelectronics from Tsinghua University, Beijing, China, in 1988 and 1994, respectively. From 1991 to 1993, she was with Arai Laboratories, Tokyo Institute of Technology, Japan, on leave from the Tsinghua University. Her Ph.D. dissertation was mainly concerned with strained semiconductor quantum well lasers and laser amplifiers. In 1994, she joined the Photonic and Wireless Devices Research Laboratories, NEC Corporation, where she was engaged in the research on semiconductor laser diodes for optical-fiber communication and became an assistant manager in 1998. She received “Merit Award” and “Contribution Award” from NEC Corporation in 1997 and 2003, respectively. She joined the Department of Electronics Engineering, Tsinghua University in 2003, as a professor, and be appointed by the Changjiang Project and the National Talents Engineering in 2005 and 2007, respectively. She was Vice Chairman of the Department from 2007-2012 and has been the Chairman of the Department from 2013. She is presently engaged in research on nano-structure optoelectronics. Professor Huang authored/co-authored more than 300 journal and conference papers. She is a senior member of the IEEE.

Yidong HuangTsinghua University,

China


Note

- 8 -

Session 1

Energy-Efficient Silicon Photonic Transmitters for Pulse-Amplitude Modulation

ABSTRACTEnergy-efficient data transmissions through optical interconnects

are required for rapidly growing short and mid-reach markets such as data centers and ultra-high-speed computing. Further increase in optical transmission speed has been hindered by power consumption and limited bandwidth resources, for which integrated optical transceivers using advanced modulation formats, such as pulse-amplitude modulation (PAM), are a promising solution. In this talk, we review our recent progress in silicon photonics for PAM transmissions, such as femtojoule PAM modulators and DAC-less CMOS-SiP integrated transmitters.

BIOGRAPHYWei Shi is an Assistant Professor in the Department of Electrical

and Computer Engineering, Université Laval, Québec, QC, Canada. He received the Ph.D. degree in electrical and computer engineering from the University of British Columbia, Vancouver, BC, Canada, in 2012, where he was awarded the BCIC Innovation Scholarship for a collaboration entrepreneurship initiative. Before joining Université Laval in 2013, he was a researcher at McGill University, Montreal, QC, Canada, where he held a Postdoctoral Fellowship from the Natural Sciences and Engineering Research Council of Canada (NSERC). His research focuses on integrated photonic devices and systems, involving silicon photonics, nanophotonics design and fabrication, CMOS-photonics co-design, high-speed optical transmission and detection, and integrated lasers. He currently directs a NSERC Strategic Partnership Grants (SPG) project on hybrid photonic integration and a NSERC Collaboration Research and Development Grants (CRD) project on high-speed silicon photonic transmitters for advanced modulation formats.

Wei ShiCenter for Optics,

Photonics, and Lasers (COPL), Laval University,

Canada


Note

- 9 -

Sess

ion

1

Engineering Wavefront for Tailoring Accelerating Beams Based on Integrated Photonic Approaches

ABSTRACTLight fields with appropriate wavefront design are capable of

propagating along curved trajectories in free space, namely, accelerating beams, which can be useful for either energy or information delivery using light. Previous methods for the realization of accelerating beams are mainly based on bulky phase-only spatial light modulator. In this talk, I will discuss how we can engineer wavefront using integrated photonic approaches with the outcome of the generation of accelerating beams.

BIOGRAPHYYujie Chen received his Ph.D. degree in Physics (Photonics) from the

Institute of Photonics, University of Strathclyde, Glasgow, UK, in 2012. He is currently an associate professor in School of Electronics and Information Technology at Sun Yat-sen University, Guangzhou, China. His research is mainly focused on the interaction of light with micro/nano-structures and their applications in integrated photonic devices. Up to date, he has authored/co-authored for about 48 peer-reviewed articles, 30 conference papers, 2 book chapters, as well as several patent applications.

Yujie ChenSun Yat-sen University,

China


Note

- 10 -

Session 1

Silicon Microring Resonators for Optical Filtering and Switching

ABSTRACTSilicon-based optical micro-ring resonators (MRRs) are very

attractive for many applications because of the ultra-compact footprint and easy fabrication. This paper gives a review of our recent work on novel silicon-based MRRs and the applications for optical filtering and switching. The following parts are included. (1) A “perfect” high-order MRR optical filter with a box-like filtering response is realized by introducing bent directional couplers; (2) A efficient thermally-tunable MRR optical filter with a graphene transparent nano-heater is realized by introducing transparent graphene nanoheaters; (3) Polarization-selective MRR optical filters are realized to work with resonances for only one of TE and TM polarizations for the first time. (4) A on-chip reconfigurable optical add-drop multiplexer for hybrid mode-/wavelength-division-multiplexing systems is realized for the first time by monolithically integrating a mode demultiplexer, four tunable MRR optical switches, and a mode multiplexer.

BIOGRAPHYProf. Daoxin Dai received the B. Eng. degree from Zhejiang

University (ZJU) in 2000, and the Ph.D. degree from the Royal Institute of Technology (Sweden) in 2005. He joined ZJU as an assistant professor in 2005 and became an associate professor in 2007, a full professor in 2011. Dr. Dai worked at UCSB as a visiting scholar from the end of 2008 until 2011. His research interests are in silicon nanophotonics for optical interconnections and optical sensing. He has published >150 refered international journals papers (including 10 invited review papers). Dr. Dai is one of Most Cited Chinese Researchers in 2015 and 2016 (from Elsevier). His paper has >4560 citations and the H-index is 38 (Google Scholar). He has been invited to give more than 40 invited talks and served as the program committee member or session chair for many top international conferences (like OFC 2013-2015). Dr. Dai was the leading Guest Editor of the Integrated Photonics special issue of Photonics Research. He is serving as the Associate Editor of the Journals of "IEEE Photonics Technology Letters", "Optical and Quantum Electronics" and "Photonics Research".

Daoxin DaiZhejiang University,

China


Note

- 11 -

Sess

ion

1

Photonic Integrated Devices on Silicon Platform for Chip-Scale Optical Interconnects and Processing

ABSTRACTSilicon photonics is a promising nanophotonic integration platform

facilitating possible integration of complete optical communication systems on a monolithic chip. In this talk, we will report recent advances in photonic integrated devices on silicon platform for chip-scale optical interconnects and processing. Design, fabrication and applications of different kinds of silicon nanophotonic devices are discussed, such as strip waveguides, slot waveguides, hybrid plasmonic waveguides, microring resonators, comb filter and interleaver.

BIOGRAPHYJian Wang received the Ph.D. degree in physical electronics

from the Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China, in 2008. He worked as a Postdoctoral Research Associate in the Optical Communications Laboratory in the Ming Hsieh Department of Electrical Engineering of the Viterbi School of Engineering, University of Southern California, Los Angeles, California, USA, from 2009 to 2011. He is currently a professor at the Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, China. He gained supports from the New Century Excellent Talents in University in 2011, the National Science Foundation for Excellent Young Scholars in 2012, and the National Program for Support of Top-notch Young Professionals in 2015.

Jian Wang has devoted his research efforts to innovations in photonic integrated devices and frontiers of high-speed optical communications and optical signal processing. He has more than 300 publications, including 3 book chapters, 2 special issues, 3 review articles, 5 invited papers, 42 tutorial/keynote/invited talks (invited talk at OFC2014, tutorial talk at OFC2016), 8 postdeadline papers, and more than 100 journal papers published on Science, Nature Photonics, Scientific Reports, Optics Express, Optics Letters, etc.

Jian WangHuazhong University of

Science and Technology, China


Note

- 12 -

Session 1

Electro-Optic Modulation and Thermo-Optic Tuning Based on Silicon-Graphene Hybrid Structure

ABSTRACTGraphene is considered to be a promising material to build active

optoelectronic device. In this talk, we firstly review recent research progress on the silicon-graphene optoelectronic devices. Then we present our works on the electro-optic modulators and the thermo-optic tunable filter based on silicon-graphene hybrid structure. By tuning the Fermi level of the graphene, we demonstrate a silicon-graphene micro-ring electro-optic (EO) modulator with modulation depth about 40%. We also propose a nanobeam EO modulator and a spatial light modulator with speed higher than 45 GHz. Thanks to the high thermo-optic coefficient of graphene, we demonstrate a tunable filter with heating efficiency about 1.5 nm/mW.

BIOGRAPHYCiyuan Qiu received the B.S. degree and M.S. degree from Tsinghua

University, Beijing, China in 2005 and 2007 respectively, and the Ph.D. degree from Rice University, Houston, USA, in 2013. He then worked as post-doc in Rice University until June 2014. He joined Shanghai Jiao Tong University, Shanghai, China, in August 2014. Dr. Qiu has published 59 journal and conference papers. He has 1 first-author paper published in Nano Letters (IF=13.779) and 1 first-author paper published in Scientific reports (IF=5.578). The total SCI citation is 381 from other researchers.

Ciyuan QiuShanghai Jiao Tong

University, China


Note

- 13 -

Sess

ion

1

Silicon Optical Modulators with Advanced Modulation Formats

ABSTRACTI will review our efforts in developing high-speed silicon Mach-

Zehnder optical modulators with large optical bandwidth. Firstly, I will introduce how to optimize the modulation efficiency, optical loss, electro-optical bandwith of the silicon optical modulator. The fabricated silicon Mach-Zehnder optical modulator has an electro-optical bandwidth of 30 GHz. When the device is optically biased at the quadrature point, it has the dynamic extinction ratios of 6.5 dB, 5.9 dB and 5.2 dB at the speeds of 40 Gbps, 50 Gbps and 64 Gbps for OOK modulation. Secondly, I will introduce a silicon 16-QAM optical modulator, which is based on four Mach-Zehnder modulators driven by four binary electrical signals. With the simple electrical driving configuration, the device generates a 16-QAM optical signal at 20 Gbaud with an error vector magnitude of 13.7%. Finally, I will introduce two types of silicon PAM-4 optical modulator. One is driven by a PAM-4 electrical signal and the other is driven by two binary electrical signals with different peak-to-peak voltages. Both two devices can generate PAM-4 optical signals at the speed of over 30 Gbaud in the wavelength of 1525-1565 nm. The corresponding bit error rates could reach as low as ~10−6, which is below the hard-decision forward error correction threshold of 3.8×10-3.

BIOGRAPHYLin Yang received his Ph. D. degree in microelectronics and solid

state electronics from Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China, in 2003. From 2003 to 2007, he was a postdoctoral fellow of Research Center for Integrated Quantum Electronics, Hokkaido University, Sapporo, Japan. He is currently a professor of State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, China. His current research interests include silicon-based photonic devices for optical interconnect, optical computing and optical communication. He is the author or co-author of 80 journal papers and 100 conference papers.

Lin YangState Key Laboratory

on Integrated Optoelectronics, Institute

of Semiconductors, CAS, Beijing, China


Note

- 14 -

Session 1

Monolithic Integration of III-V Quantum Dot Lasers on Silicon for Silicon Photonics

ABSTRACTThe availablility of silicon lasers is the key technology for the whole Si

photonics industry. But the indirect bandgap of silicon is a severe limitation, and, despite recent advances, these devices will not, in the foreseeable future, outperform their III-V counterparts. Much effort has been directed toward hybrid integration of III-V lasers with Si photonics platforms. Although impressive results have been achieved, on a longer term, large-scale integration of photonics circuits will rely on monolithic integration of laser sources on silicon.

In this talk, I will review our recent progress made in the direct growth of III-V light sources on silicon. I firstly briefly address issues related to the III-V/Si substrates itself before moving to results on III-V quantum lasers monolithically integrated on Ge, Ge-on-Si, and Si substrates.

BIOGRAPHY Siming Chen received his MSc and PhD degrees in Electrical

Engineering from the University of Sheffield, U.K., in 2010 and 2014, respectively. In Sep 2013, he joined the Department of Electronic and Electrical Engineering at University College London, U.K., as a research associate. He is currently a Royal Academy of Engineering (RAEng) Research Fellow hosted by University College London. His major research interest concentrates on monolithic integration of III-V compound semiconductors and optoelectronic devices on silicon substrates.

Since 2011, Chen has published over 50 papers in international journals and conference proceedings, such as Nature Photonics, ACS Photonics, MRS Bulletin, Applied Physics Letters, Optics Express and IEEE JSTQE, etc. Chen’s research achievements have been widely reported/highlighted by over 20 tech magazines, newspapers, and websites world-wide, including Daily Mail, OSA: optics & photonics, Technology.org, Photonics.com, Headlines & Global News, Science Daily, Nanotechnology Now, SPIE Newsroom, Semiconductor Today, IET, Phys.org and Space Daily, etc. Chen has also filed 5 international patents, with 1 granted already.

Siming ChenUniversity College

London, UK


Note

- 15 -

Sess

ion

1

Physics-Enabled Design and Innovation in Silicon Photonics: From Novel Devices to High-Density Waveguides Integration

ABSTRACTSilicon photonics is making rapid advances in recent years.

Currently, basic device building blocks have become widely available. In the future, innovation opportunities may continue to emerge in devices and integration. At the device level, novel structures (such as photonic crystals and resonators) show promise to reduce device size and power consumption, yet they may bring sophisticated physics that cannot be easily analyzed by common simulation tools such as FDTD. Advanced physics theory is needed to analyze performance of such novel devices. Furthermore, advanced device physics and design can also help to prevent device failure in fabrication. We will show an example how this helped to successfully fabricate Si photonic devices on a CMOS fab line that has not done photonics before. Lastly, for large-scale integration, physics-based theory can also help. High-density waveguide integration at half-wavelength waveguide pitch has been demonstrated with very low crosstalk, assisted by advanced physics theory. Potential applications of such high-density waveguides in optical phased arrays and space-division multiplexing will be discussed.

BIOGRAPHYWei Jiang received his B.S. degree in physics from Nanjing

University, Nanjing, China, in 1996, and his M.A. degree in physics and his Ph.D. degree in electrical and computer engineering from the University of Texas, Austin, in 2000 and 2005, respectively.

He is currently a professor in the Department of Quantum Electronics and Optical Engineering, College of Engineering and Applied Sciences, Nanjing University, Nanjing, China. Prior to joining Nanjing University, he was an assistant professor and then an associate professor in the Department of Electrical and Computer Engineering of Rutgers, the State University of New Jersey, USA. His research interests include silicon photonics, photonic crystals, nanophotonics, and their applications in communications, computing, and sensing.

Dr. Jiang received DARPA Young Faculty Award in 2012 and IEEE Region I Outstanding Teaching Award in 2013, among other honors.

Wei JiangNanjing University,

China


Note

- 16 -

Session 1

Surface-Wave Photonic Crystals

ABSTRACTPhotonic crystals, also known as photonic bandgap (PBG) materials,

can forbid the propagation of electromagnetic (EM) waves in a certain frequency range in all directions, but they generally lack subwavelength features. In parallel, EM modes supported on periodically textured metal surfaces, which are commonly termed as spoof (or designer) surface plasmons, possess spatial scales typically much smaller than the wavelength, but they generally do not have PBG concepts. Here we show that it is possible to merge these two fields by creating surface-wave photonic crystals. Many device concepts in the context of photonic crystals can thus be transferred and applied directly to the manipulation of surface waves at the subwavelength scale.

BIOGRAPHYDr. Baile Zhang is an Associate Professor in the Division of Physics

and Applied Physics, School of Physical and Mathematical Sciences, at Nanyang Technological University, Singapore. He received his Ph.D. in 2009 from MIT, following his B.S. degree in 2003 and M. S. degree in 2006 from Tsinghua University in Beijing, all majored in Electrical Engineering.

Baile ZhangNanyang Technological University, Singapore


Note

- 17 -

Sess

ion

1

Integrated Devices for Optical Vortices

ABSTRACTIntroduced by Allen et al., it has been realized that light can

carry orbital angular momentum (OAM) in addition to the spin angular momentum (SAM). Independent of the polarization state, light with an azimuthal phase dependence of exp(ilφ) has OAM lћ per photon. The value of l (the topological charge), as a new dimensionality, can be valued with any integer. Having l spiral phase fronts and a transverse component of the Poynting vector perpendicular to the propagating direction, such kind of light is also known as optical vortex.

Aim to explore the benefit introduced by optical vortex, we have proposed and demonstrated several photonic integrated devices. In this article, some representative devices of our recent work would be briefly introduced. They are the integrated “Cobweb” emitter with a wide switching range of OAM modes, integrated “Cogwheel” emitter to generate optical superimposed vortex beam and plasmonic vortex devices.

BIOGRAPHYDr. Xue Feng received his BS, MS and PhD degrees in Electrical

Engineering from Tsinghua University in 1999, 2002 and 2005, respectively. Since 2005, he has been working in Department of Electronic Engineering, Tsinghua University, Beijing, China. His major research interest is focused on micro/nano-structure optoelectronics, silicon photonics, and integrated optoelectronic devices. As author and co-author, he has published more than 100 journal or conference papers.

Xue FengTsinghua University,

China


Note

- 18 -

Session 1

China Silicon Photonics Platform in a Multi Project Wafer Service

ABSTRACTRapid progress has been made in recent years in the field of silicon

photonics in China. Foundry processes now become an essential issue in the whole design and fabrication flow. Shared shuttle run services are ideal for rapid and relatively inexpensive prototyping. We present the silicon photonic platform in China that offers monolithically integrated active and passive silicon photonics devices through the MPW (multi-project wafer) service. A great number of devices have been demonstrated in this platform, which include low-loss waveguides, efficient grating couplers, passive optical devices, high-speed modulators and germanium waveguide photo-detectors.

BIOGRAPHYJunbo Feng received the B.E. and Ph.D. degrees from Huazhong

University of Science and Technology, China in 2004 and 2009, respectively. He is currently a senior engineer in the 38th Institute of China Electronics Technology Group Corporation. His research topics focus on silicon photonics and optical integration technologies. He studied in the Electronic Engineering Department of Georgia Tech. from January 2007 to June 2008. After that, he continued his research in Peking University and became a post doctor in Tsinghua University until 2011. He has authored more than 30 journal and conference publications and a book chapter, and owned more than 10 patents. He presided over 5 national and provincial projects in the past five years. He obtained Youth Talent Support Program and First Class Prizes of the State Scientific and Technological Progress Award of CETC38.

Junbo FengChina Electronics Technology Group Corporation, China

The 9th International Conference on Information Optics and PhotonicsSession 1——Oral Reports

- 19 -

Sess

ion

1

CIOP-2017-0773 Relative Intensity Noise of an InAs/GaAs Quantum Dot Laser Epitaxially Growing on Germanium

Cheng Zhou1, Yueguang Zhou2, Chunfang Cao3, Jiangbing Du1, Qian Gong3, Cheng Wang21 State Key Laboratory of Advanced Optical Communication Systems and Networks, Department of Electronic Engineering, Shanghai Jiao Tong University; 2 School of Information Science and Technology, ShanghaiTech University; 3 State Key Laboratory of Functional Materials for Informatics, Shanghai Institute

of Microsystem and Information Technology, Chinese Academy of Sciences

Integration of photonic circuits on the CMOS-compatible silicon (Si) platform is increasingly demanded for cost-effective applications in data centers, access networks, and supercomputers. Nowadays, a large variety of Si-based optical modulators, detectors, and passive photonic devices have been successfully demonstrated. However, it remains challenging to monolithically integrate semiconductor lasers on Si. Fortunately, III-V quantum dot (Qdot) lasers are weakly sensitive to growth defects arising from the lattice mismatch between the III-V compounds and Si, and epitaxially-grown InAs/GaAs Qdot lasers on germanium (Ge), Ge-Si, and Si were reported in recent years. It was shown that the static performances including the lasing threshold and the output power were slightly degraded in comparison with their counterparts grown on the GaAs substrate, which was attributed to the high density of threading dislocation defects. However, there are few studies of the defect impacts on the dynamical characteristics. Among the laser dynamics, the relative intensity noise (RIN) increases the bit error rate during the data transmission and hence limits the maximum communication rate.

In this work, we report the RIN properties of an InAs/GaAs Qdot laser epitaxially grown on the Ge substrate. The laser was grown on a Ge [100] wafer with 6° miscut towards [111] plane, using the gas-source molecular beam epitaxy technique. A GaAs buffer layer grew on the Ge substrate, followed by the Qdot laser structure with an active region consisting of five-stacked InAs Qdot layers. Ridge-waveguide laser diodes were fabricated with cavity length of 4.4 mm and ridge width of 6.0 μm. Both cavity facets were as-cleaved. During the experiment, the laser temperature is kept constant at 20 ℃ using a thermo-electric cooler. The lasing threshold is 300 mA, and the optical spectrum peaks around 1045 nm. In the measurement of the laser’s RIN, the background thermal noise and the photodiode shot noise are carefully removed.

Above threshold, the RIN of Ge-based Qdot laser is around -90.0 dB/Hz for frequencies less than 0.5 GHz, and it decreases to be lower than -115.0 dB/Hz for frequencies of 4.0–6.0 GHz. The high RIN at the low frequencies is due to excess noises arising from the current source, the thermal fluctuation and the multimode partitioning effect. The RIN exhibits a peak around 1.0 GHz owing to the relaxation oscillation resonance. In addition, the RIN shows another peak around 9.0 GHz, which is not common in the RIN spectrum of semiconductor lasers. This phenomenon can be attributed to the split of the longitudinal cavity modes resulting from the Qdot size fluctuations. Beyond 12.0 GHz, the RIN remains constant and lower than -115.0 dB/Hz. Increasing the bias current reduces the RIN down to a minimum level of about -120.0 dB/Hz. In contrast, an InAs Qdot laser growing on the GaAs substrate using the same layer structure and the same growth technique exhibits a minimum RIN of -135.0 dB/Hz. That is, the RIN performance of the Ge-based Qdot laser deteriorates by about 15 dB/Hz, which is mainly due to the growth dislocation defects.Key words: silicon photonics; semiconductor lasers; quantum dots; fluctuations, relaxations, and noise

CIOP-2017-1792 Measure and Correct Orbital Angular Momentum Spectra of Light Beams

Peng Zhao, Xue Feng, Yidong HuangDepartment of Electronic Engineering, National Laboratory for Information Science and Technology, Tsinghua University

In 1992, Allen et al. established the relation between light beam with an azimuthal phase distribution of exp(ilφ) and the orbital angular momentum (OAM), while the integer number of l names as the OAM order or the topological charge and the carried OAM is lħ per photon. OAM can be employed in plenty applications, such as optical communication, quantum information processing and optical imaging, since it provides an infinite and additional dimension of light. In such applications, measuring OAM spectrum of light is necessary, however, although many methods have been proposed, several issues are still not well addressed, such as sensitivity to the tilt of light and lack of relative phases between OAM spectrum coefficients. To obtain the whole information carried by the OAM light beam, the OAM spectrum has to be measured in terms of intensity and phase. Thus, it is necessary to measure the complex optical field distribution. In this work, an interference method is proposed and demonstrated to measure the complex optical field of a light beam. The scheme consists of a laser source operating at 1550 nm, a spacial light modulator (SLM) for generating objective light beams under test, an M-Z interferometer and a charge coupled device (CCD) camera for measuring the interference patterns. With the measured light field, the complex OAM spectrum of light can be obtained by mode matching. Furthermore, the small tilt angle of the objective light can be extracted from the field. Then with the obtained angle tilt, the dispersion of the OAM spectrum due to the tilt can be corrected.Key words: orbital angular momentum; interference; optical field

日程初稿-终稿-3 19日程初稿-终稿-3 20日程初稿-终稿-3 21日程初稿-终稿-3 22日程初稿-终稿-3 23日程初稿-终稿-3 24日程初稿-终稿-3 25日程初稿-终稿-3 26日程初稿-终稿-3 27日程初稿-终稿-3 28日程初稿-终稿-3 29日程初稿-终稿-3 30日程初稿-终稿-3 31日程初稿-终稿-3 32日程初稿-终稿-3 33

session 1: photonic integration and optical interconnect...energy-efficient silicon photonic...

Documents