Page 47 - Market Analysis Report of Optical Communications Field in China & Global market 2021

Analysis of the Future Development Trend of Figure 1. The future optimization direction of the transport the design and fabrication technology of fan-in and fan-out
network architecture optical devices matching multi-core fibers have gradually
Optical Communication Technology matured. At present, there are two main technical routes:
fusion tapering and femtosecond direct writing, and the
coupling loss can be reduced to less than 1dB.

Figure 2. Typical space division multiplexing fiber structure

3.2 High-capacity transmission link technology
There are two main aspects to the improvement of the
capacity of the optical information transmission link, one
is the improvement of the single-wave rate, and the other is
the channel multiplexing.
3.2.1 Single-wave rate enhancement technology
The increase in single-wave rate is mainly based on the 3.3 Large-capacity switching node technology
development of semiconductor lasers, detector performance At present, the nodes of the optical network are mainly
and external modulation and high-order modulation based on the wavelength switching method, supporting
technologies. Currently, single-wave 100G bit rate 20-dimensional WSS, and the medium and long-term
transmission can be realized based on PAM4 modulation space division multiplexing optical fiber technology and
technology. The maturity of silicon-based thin-film switching technology will have important application
modulators and higher-order modulation technologies will scenarios in ROADM nodes.
further increase the single-wave transmission rate in the 3.3.1 Optical backplane technology
future. ROADM nodes constructed by high-dimensional WSS
3.2.2 Channel multiplexing technology have many internal connections, and traditional connection
In the 1990s, in order to expand the capacity of the single methods cannot effectively support the expansion of WSS
optical fiber, a third-generation optical communication
system based on single-mode optical fiber and wavelength dimensions. Nowadays, the number of fiber connections
division multiplexing (WDM) technology emerged; in the in the data center has been greatly reduced through MPO.
early 21st century, dense wavelength division (DWDM) In the future, the data center will use optical backplanes
and Optical amplification technology realizes ultra-long and space division multiplexing fibers pre-connection
distance and ultra-large-capacity information transmission. technology to realize zero fiber arrangement.
With the continuous development of technology, it has Figure 3. The development of ROADM nodes from a large
become more and more difficult to achieve breakthroughs number of fiber front panel connections to optical backplane
in single-fiber transmission capacity from the dimensions space division multiplexing fiber pre-connections
of time, frequency, and polarization in the future. Space
division multiplexing will be an important direction
to solve the transmission capacity problem in the next
stage. Space division multiplexing technology is realized
by integrating multiple cores in the single optical fiber,
according to the number of optical modes supported by the
core, it can be divided into single-mode multi-core fiber
(MCF) and few-mode multi-core fiber (MC-FMF). MCF
can be further divided into weakly coupled MCF and strong
coupled MCF, the requirements of weakly coupled MCF 3.3.2 CDC-ROADM technology
for the system are the closest to the current SMF. Based At present, the main form of optical switching node equipment
on the existing technology, the application of the weakly is CD-ROADM, which can realize wavelength independence
coupled MCF system is the easiest to realize. At present, and direction independence. In the future, CDC-ROADM
the leading manufacturers of the optical fiber industry have technology will gradually replace the CD-ROADM solution.
begun to deploy multi-core optical fibers, and there are CDC is the most flexible ROADM equipment form, which can
some application cases. Chinese operators have also carried support any wavelength and any direction on any up-drop ports,
out space division multiplexing technology and application and realize the configuration according to the required quantity.
research to explore the application prospects of new optical CDC-ROADM usually requires larger-dimensional WSS, such as
fiber technologies in operator networks. At the same time, 32-dimensional/64-dimensional WSS. Based on 20-dimensional
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