• Special Issue
  • Integrated Photonics: Challenges and Perspectives
  • 24 Article (s)
Silicon and hybrid silicon photonic devices for intra-datacenter applications: state of the art and perspectives [Invited]
Yu Li, Yu Zhang, Lei Zhang, and Andrew W. Poon
We review the state of the art and our perspectives on silicon and hybrid silicon photonic devices for optical interconnects in datacenters. After a brief discussion of the key requirements for intra-datacenter optical interconnects, we propose a wavelength-division-multiplexing (WDM)-based optical interconnect for intra-datacenter applications. Following our proposed interconnects configuration, the bulk of the review emphasizes recent developments concerning on-chip hybrid silicon microlasers and WDM transmitters, and silicon photonic switch fabrics for intra-datacenters. For hybrid silicon microlasers andWDM transmitters, we outline the remaining challenges and key issues toward realizing low power consumption, direct modulation, and integration of multiwavelength microlaser arrays. For silicon photonic switch fabrics, we review various topologies and configurations of high-port-count N-by-N switch fabrics using Mach–Zehnder interferometers and microring resonators as switch elements, and discuss their prospects toward practical implementations with active reconfiguration. For the microring-based switch fabrics, we review recent developments of active stabilization schemes at the subsystem level. Last, we outline several large challenges and problems for silicon and hybrid silicon photonics to meet for intra-datacenter applications and propose potential solutions.Optoelectronics;Diode laser arrays;Diode lasers;Laser resonators
Photonics Research
  • Publication Date: Jul. 31, 2015
  • Vol. 3, Issue 5, 05000B10 (2015)
Lowering the energy consumption in silicon photonic devices and systems [Invited]
Zhiping Zhou, Bing Yin, Qingzhong Deng, Xinbai Li, and Jishi Cui
We review current silicon photonic devices and their performance in connection with energy consumption. Four critical issues are identified to lower energy consumption in devices and systems: reducing the influence of the thermo-optic effect, increasing the wall-plug efficiency of lasers on silicon, optimizing energy performance of modulators, and enhancing the sensitivity of photodetectors. Major conclusions are (1) Mach–Zehnder interferometer-based devices can achieve athermal performance without any extra energy consumption while microrings do not have an efficient passive athermal solution; (2) while direct bonded III–V-based Si lasers can meet system power requirement for now, hetero-epitaxial grown III–V quantum dot lasers are competitive and may be a better option for the future; (3) resonant modulators, especially coupling modulators, are promising for low-energy consumption operation even when the power to stabilize their operation is included; (4) benefiting from high sensitivity and low cost, Ge/Si avalanche photodiode is the most promising photodetector and can be used to effectively reduce the optical link power budget. These analyses and solutions will contribute to further lowering energy consumption to meet aggressive energy demands in future systems.
Photonics Research
  • Publication Date: Aug. 06, 2015
  • Vol. 3, Issue 5, 05000B28 (2015)
Silicon and silicon nitride photonic circuits for spectroscopic sensing on-a-chip [Invited]
Ananth Z. Subramanian, Eva Ryckeboer, Ashim Dhakal, Frédéric Peyskens, Aditya Malik, Bart Kuyken, Haolan Zhao, Shibnath Pathak, Alfonso Ruocco, Andreas De Groote, Pieter Wuytens, Daan Martens, Francois Leo, Weiqiang Xie, Utsav Deepak Dave, Muhammad Muneeb, Pol Van Dorpe, Joris Van Campenhout, Wim Bogaerts, Peter Bienstman, Nicolas Le Thomas, Dries Van Thourhout, Zeger Hens, Gunther Roelkens, and Roel Baets
There is a rapidly growing demand to use silicon and silicon nitride (Si3N4) integrated photonics for sensing applications, ranging from refractive index to spectroscopic sensing. By making use of advanced CMOS technology, complex miniaturized circuits can be easily realized on a large scale and at a low cost covering visible to mid-IR wavelengths. In this paper we present our recent work on the development of silicon and Si3N4-based photonic integrated circuits for various spectroscopic sensing applications. We report our findings on waveguide-based absorption, and Raman and surface enhanced Raman spectroscopy. Finally we report on-chip spectrometers and on-chip broadband light sources covering very near-IR to mid-IR wavelengths to realize fully integrated spectroscopic systems on a chip.
Photonics Research
  • Publication Date: Aug. 28, 2015
  • Vol. 3, Issue 5, 05000B47 (2015)
InP photonic circuits using generic integration [Invited]
K. A. Williams, E. A. J. M. Bente, D. Heiss, Y. Jiao, K. ?awniczuk, X. J. M. Leijtens, J. J. G. M. van der Tol, and M. K. Smit
Photonics Research
  • Publication Date: Aug. 28, 2015
  • Vol. 3, Issue 5, 05000B60 (2015)
Laser-annealing-made amplified spontaneous emission of “giant” CdSe/CdS core/shell nanocrystals transferred from bulk-like shell to quantum-confined core
Chen Liao, Kai Fan, Ruilin Xu, Huichao Zhang, Changgui Lu, Yiping Cui, and Jiayu Zhang
“Giant” CdSe/CdS core/shell nanocrystals (NCs) were synthesized with thick CdS shell (15 monolayers), and the x-ray diffraction (XRD) measurement indicates there is a zinc blende phase in the thick CdS shell, whereas it transformed into wurtzite phase under 5 min radiation with a 400 nm, 594 μJ∕cm2 femtosecond (fs) laser beam. The evolution of the NCs’ spontaneous emission under the fs laser radiation was recorded with a Hamamatsu streak camera. The as-synthesized NCs exhibit an amplified spontaneous emission (ASE) at 530 nm, which comes from a bulk-like CdS shell due to the interfacial potential barrier, which could slow down the relaxation of holes from the shell to the core. After being annealed by an fs laser, the ASE of the g-NCs is transferred from a bulk-like CdS shell to a quantum-confined CdSe core because the phase transformation determined with the XRD measurement could remove the interfacial barrier. Besides the ASE at 643 nm, two shorter-wavelength ASE peaks at 589 and 541 nm, corresponding to optical transitions of the second (1P) and third (1D) electron quantization shells of the CdSe core, also appear, thus indicating that Auger recombination is effectively suppressed.materials
Photonics Research
  • Publication Date: Aug. 07, 2015
  • Vol. 3, Issue 5, 05000200 (2015)
Enhanced optical Kerr nonlinearity of MoS2 on silicon waveguides
Linghai Liu, Ke Xu, Xi Wan, Jianbin Xu, Chi Yan Wong, and Hon Ki Tsang
Photonics Research
  • Publication Date: Aug. 07, 2015
  • Vol. 3, Issue 5, 05000206 (2015)
Multicolored sideband generation based on cascaded four-wave mixing with the assistance of spectral broadening in multiple thin plates
Peng Wang, Jun Liu, Fangjia Li, Xiong Shen, and Ruxin Li
Photonics Research
  • Publication Date: Aug. 13, 2015
  • Vol. 3, Issue 5, 05000210 (2015)
Broadband ultrafast nonlinear optical response of few-layers graphene: toward the mid-infrared regime
Lili Miao, Yaqin Jiang, Shunbin Lu, Bingxin Shi, Chujun Zhao, Han Zhang, and Shuangchun Wen
Gapless linear energy dispersion of graphene endows it with unique nonlinear optical properties, including broadband nonlinear absorption and giant nonlinear refractive index. Herein, we experimentally observed that fewlayers graphene has obvious nonlinear absorption and large nonlinear refraction, as investigated by the Z-scan technique in the mid-infrared (mid-IR) regime. Our study may not only, for the first time to our knowledge, verify the giant nonlinear refractive index of graphene (~10?7 cm2∕W) at the mid-IR, which is 7 orders of magnitude larger than other conventional bulk materials, but also provide some new insights for graphene-based mid-IR photonics, potentially leading to the emergence of several new conceptual mid-IR optoelectronics devices.
Photonics Research
  • Publication Date: Aug. 13, 2015
  • Vol. 3, Issue 5, 05000214 (2015)

Integrated Photonics, which has achieved great success since Integrated Photonics was proposed by Dr. Miller in 1969. Currently various materials and technologies have been developed to realize photonic integrated circuits for many applications. The comprehensive reviews for the state-of-the-art for all aspects of integrated photonics will be very helpful for this field. It is even more important to have a deep discussion on the challenges and perspectives for integrated photonics, which will be definitely very beneficial for the young scientists and students.