Space-division multiplexing

We study the ultimate limit of core density and inter-core crosstalk properties in uncoupled multi-core fibers (MCFs), mode density of multimode fibers, silicon photonics grating couplers as fan-in fan-out (FI/FO) devices for MCFs.

Ongoing projects:

Silicon Photonic Integrated Circuits (PIC) for Reconfigurable Optical Add/Drop Multiplexer (ROADM) in Multicore Fibre (MCF) Communication 


The information revolution has modified our life style in terms of work, services, medical treatment, entertainment, etc. Nowadays, optical fibre networks are capable of transmitting a large amount of information by means of short pulses of light. It has been thought that the transmission capacity of optical fibres would be inexhaustible. However, the fast increasing demands from HDTV, IPTV, rich media services, as well as business services are pushing the amount of information transmitted over traditional optical fibre networks close to their ultimate capacity limitation. Multicore fibre communication, where multiple cores are introduced in a single fibre, exploits space as a new dimension, allowing a many-fold increase of capacity. However, achieving a higher transmission capacity is only one requirement for future networks. In order to achieve a real commercial success, this new technology must also support photonic routing in future multicore fibre network nodes, where much functionality still remains to be demonstrated. This project will explore integrated solutions for the required functionalities in multicore fibre communication, targeting low loss and low energy consumption of network nodes. The project will develop a compact silicon chip integrating all the networking functionalities, aiming to demonstrate a powerful module and pushing multicore fibre communications one step closer to reality.
 Source of funding: Danish Council for Independent Research
 Duration: 2013-2016 
 Members: Yunhong Ding
 Intra-group collaborators: Toshio MoriokaFeihong Ye

Enhanced Spatial Light Control in Advanced Optical Fibres (e-space) 


Since the invention of the laser, the ability of controlling the properties of light and its interaction with matter has led to major breakthroughs in a wide area of applications, including telecommunication, biology and medicine. Our information society relies on narrow beams of light being transmitted around the globe using optical fibres the width of a human hair. Tiny beams of light can also be used to manipulate small particles, including individual cells, with huge potential in diagnostic and therapy.

However, the shape of the light beam itself has until now received very little attention. Being able to mould the spatial properties of light could have a huge impact on those applications. Higher capacities could be carried over optical fibres if beams with different spatial profiles could be transmitted together, thus resolving a foreseen shortage of bandwidth in the near future. New tools including additional degrees of freedom could be developed for enhanced interaction of light with matter, with huge potential impact in imaging, diagnostic and cell manipulation.

Interestingly some common technology platforms could be used for such distant applications as telecommunications and biology. It is these technologies we propose to explore and develop in this highly interdisciplinary project. In particular, we will study how advanced beam shaping techniques and new optical fibres specially developed to transmit these beams can be used for a wide range of applications.

This project proposes to demonstrate how an enhanced control of the field distribution of light can lead to breakthroughs in a wide range of applications, including high-capacity optical fibre communications and the emerging field of nano-biophotonics.

 Source of funding: Danish Council for Strategic Research (ref. 12-131868) (
 Duration 2013-2016
 Members: Toshio MoriokaRameez Asif

Ultrahigh Capacity Photonic Transport Beyond Pbit/s

Over the last twenty years, optical fiber communication technologies have succeeded in increasing its transmission capacity by more than three orders of magnitude with the invent of optical fibers, semiconductor lasers and optical amplifiers, etc., thus realizing a several Tbit/s per fiber transmission system. However, the present optical communication technologies, primarily based on TDM/WDM technologies, have begun to reveal their ultimate physical limitations, namely, Shannon limit combined with fiber nonlinearities, fiber fuse (fiber melt-down), and the optical amplifier bandwidth. This project aims at developing novel photonic transport schemes to go beyond these limitations and to transport and handle well over Pbit/s capacity of information in an energy-efficient way by developing innovative optical fibers, multiplexing, amplification and switching technologies. 
 Source of funding: Internal funding of DTU Fotonik
 Duration 2012-2015
 Members: Toshio MoriokaFeihong Ye
 Major achievements: 
  • Developed an analytical tool for crosstalk estimation and core positions optimization in trench-assisted MCFs
 Relevant publications:
  1. F. Ye, J. Tu, K. Saitoh, K. Takenaga, S. Matsuo, and T. Morioka, "A New and Simple Method for Crosstalk Estimation in Homogeneous Trench-Assisted Multi-Core Fibers," in Proc. ACP, (Shanghai, China), paper AW4C.3, Nov. 2014.
  2. F. Ye, J. Tu, K. Saitoh, and T. Morioka, "Simple Analytical Expression for Crosstalk Estimation in Homogeneous Trench-Assisted Multi-Core Fibers," in Optics Express, no. 22, vol. 19, pp. 23007--23018, Sept. 2014.
  3. F. Ye, J. Tu, K. Saitoh, and T. Morioka, "Theoretical Investigation of Inter-core Crosstalk Properties in Homogeneous Trench-Assisted Multi-Core Fibers," in IEEE Photonics Society Summer Topicals Meeting Series, (Montreal, Canada), paper TuE4.2, July 2014.
  4. F. Ye, J. Tu, K. Saitoh, H. Takara, and T. Morioka, "Wavelength-dependent Crosstalk in Trench-Assisted Multi-Core Fibers," in Proc. OECC/ACOFT, (Melbourne, Australia), paper TU5C-1, July 2014.
  5. F. Ye and T. Morioka, ''Interleaved Core Assignment for Bidirectional Transmission in Multi-Core Fibers,'' in Proc. ECOC, (London, UK), paper We.2.D.5, Sept. 2013.
  6. F. Ye, C. Peucheret, and T. Morioka, ''Capacity of Space-Division Multiplexing with Heterogeneous Multi-Core Fibers,'' in Proc. OECC/PS, (Kyoto, Japan), paper WR2-3, July 2013.


Finished projects:

 Mode Division Multiplexing for Ultra-Large Capacity Backbone Optical Transmission Systems

 Source of funding:  Danish Research Council for Technology and Production Sciences (ref. 10-093299) (
 Duration  2011-2012

 Integrated Components for Mode Division Multiplexing

 Source of funding:  H. C. Ørsted postdoctoral grant at the Technical University of Denmark