This blog post is part of a series called “CommScope Definitions,” in which we will
explain common terms in communications network infrastructure.
photonics (SiPh) is a technology that involves data being transferred among
computer chips by optical rays. On the surface, it seems simple, but it can
actually be difficult to understand. Perhaps it is best to compare it to an electrical
In the early
days of electrical circuits, there were discrete components (e.g., transistors,
capacitors, resistors, etc.) that were connected with traces on a printed
circuit board. In order to reduce size
and cost, many discrete components were formed adjacently and interconnected on
a single silicon substrate to create
integrated circuits (i.e. chips). Over
time, the types of components that could be formed on chips continued to expand
while their size and power consumption shrank at dramatic rates (per Moore’s
law). We now have billions of interconnected
components per chip, each at a negligible cost.
of silicon photonics is to enable
the same cost effective component integration in the optical domain. Specifically, optical components (e.g.
lasers, splitters, modulators, combiners, etc) are interconnected with
transparent pathways or waveguides for light to travel through, much like
electricity runs through traces on a circuit board. The industry has focused on leveraging the
investments made in silicon by the electrical chip industry wherever possible.
SEE ALSO: Silicon
photonics market to grow 21% from
2016 to 2022
Although the technical
capability of SiPh has continually progressed, two related challenges have kept
the cost of SiPh solutions high:
is not possible to form lasers directly in silicon. Instead, lasers are made
out of other materials, and their output (light) is coupled into the waveguides.
waveguides are small, making interconnections to and from the chips difficult
and expensive. Specifically, SiPh
waveguides are less than half a micron in diameter which is about 1/20th the diameter of today’s standard
single mode fiber. Various alignment
techniques are available, but they are expensive.
that is having significant market impact is to replace the pure silicon
substrate with silicon dioxide (i.e., glass).
The resulting circuit is called Photonic
Light Circuit (PLC). The types of components
that can be formed on PLCs is limited, but the use of glass substrates allows six
times larger waveguides which reduces the alignment challenges to other
components like lasers. The combination
of technologies is helping solve challenges and driving down the cost of high speed photonics. It also redefines the
industry’s direction from purely “silicon photonics” to the wider field of “integrated
photonics.” CommScope tracks these developments closely as they impact
the optimal choice of fiber type in multiple markets we serve.
Are you seeing intriguing
developments around integrated photonics?
Comment here, and we’ll have a discussion that will keep all of us up to
date with architectural advancements in this exciting field.