Integrated photonics research in China is a relatively young field compared
to lasers and fiber optics, but it is on the rise.
National 863 high-tech projects
One of the recently funded 863 projects on “Photonics and
monolithic integration research (Pamir)” (launched in 2010)
is titled, “Photonic integration technology and its system
applications.” Led by Ninghua Zhu of the Institute of Semiconductors, CAS, the project involves the following ten
institutions: the Institute of Semiconductors, CAS; BUPT;
Zhejiang University; Peking University; Nanjing University;
the Wuhan Research Institute of Posts and Telecommunications; Southeast University; UESTC; Fudan University and
Huawei Technologies Co., Ltd.
The main topics it will address are:
c Ultra-small and ultra-high-capacity Si-based PIC
design and fabrication,
c Si-based monolithic photonic integrated 100 Gb/s
c InP monolithic integrated 10 3 10 Gb/s transmitters
for long-distance transmission,
c InP monolithic integrated 16 3 2. 5 Gb/s transmitters
for wavelength-division multiplexing passive optical
c InP monolithic integrated 8 3 6 GHz transmitters for
radio-over-fiber applications, and
c System demonstration and applications.
Major projects from the National Natural Science
Foundation of China
The National Natural Science Foundation of China recently
funded a major project (launched in 2010), titled “Basic
research on high-speed semiconductor integrated optoelectronic devices.” Also led by Ninghua Zhu of the Institute of
Semiconductors, CAS, the project involves the following five
institutions: the Institute of Semiconductors, CAS; Nanjing
University; UESTC; Tsinghua University and SJTU. The
main topics are:
c 10-channel InP transmitter PICs capable of a 100 Gb/s rate.
c 100 Gb/s all-optical wavelength conversion with a semiconductor optical amplifier integrated with a distributed
Bragg reflector laser.
Various key state laboratories, university labs and research
institutions in China have demonstrated many “firsts” in
China and the world for research relevant to integrated
[ Metal-coated silica toroidal microcavities ]
Illustration by Phil Saunders
Adapted from Yun-Feng Xiao et al., Phys. Rev. Lett. 105, 153902 (2010).
Schematic of a metal-coated silica toroidal microcavity
supported by a silicon pillar. (Inset) False-color representation
of the electric field for an exterior plasmonic WGM.
photonics. Here, we showcase a number of representative
groups from Tsinghua University, CAS, Peking University,
and Zhejiang University on work related to advanced laser
structures, monolithic photonic integration technologies,
photodetectors, silicon photonic devices and microsystems.
Over the past decade, Yi Luo’s group at Tsinghua University has been addressing significant issues in the design and
fabrication of electroabsorption modulated lasers (EMLs), a
key component for high-speed fiber communication systems.
EMLs monolithically integrate a DFB laser with an electroabsorption modulator (EAM), and they constitute one of the
most successful monolithic PICs to date. One key challenge
facing researchers is figuring out how to realize wavelength
compatibility, namely by ensuring that the DFB laser wavelength falls on the longer wavelength side of the excitonic
peak of the EAM.
Luo’s group solved this problem by adopting the identical
epitaxial layer (IEL) structure, in which the DFB laser and the
EAM share the MQW layer. The IEL integration scheme greatly
simplifies device fabrication, since no additional regrowth step
is involved. Luo’s group was among the first in the world to propose and independently realize the IEL structure. By adopting
the IEL integration technique and suppressing package-induced
parasitic crosstalk between the laser and the modulator as well
as optical and electrical crosstalk, Luo and his colleagues were
the first in China to fabricate 2.5Gb/s, 10Gb/s and 40Gb/s
EML transmitter modules in 1998, 2003 and 2007, respectively.
Recently, Luo’s group demonstrated an EML module exhibiting