Data information transfer using complex optical
fields: a review and perspective
(Invited Paper)
Jian Wang (王 健)*
Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information,
Huazhong University of Science and Technology, Wuhan 430074, China
*Corresponding author: jwang@hust.edu.cn
Received December 18, 2016; accepted January 20, 2017; posted online February 13, 2017
Tailored complex optical fields, may find applications in optical manipulation, imaging, microscopy, quantum
information processing, and optical communications. Here, we focus on data information transfer for optical
communications using complex optical fields. We review recent research progress in complex optical field
modulation, multiplexing, and multicasting for data information transfer on different platforms of waveguides,
free space, and fiber. Challenges and perspectives are also discussed.
OCIS codes: 060.4510, 050.4865, 060.4080, 060.4230.
doi: 10.3788/COL201715.030005.
One distinct feature of photons and light is their multiple
physical dimensions including wavelength/frequency,
time, complex amplitude, polarization, and spatial struc-
ture, as shown in Fig.
1. Very recently, the spatial structure
of light has attracted increasing interest in optical commu-
nications to address the emerging capacity crunch
[1]
. One
typical example exploiting the spatial structure is a twisted
light carrying orbital angular momentum (OAM)
[2]
, which
has a spiral phase structure similar to the natural spiral
phenomenon (e.g., helical stairs). An OAM-carrying light
is one type of complex optical fields. In general, complex
optical fields have comp lex spatial distributions and/or
complex temporal waveforms, as shown in Fig.
2. The com-
plex spatial distributions include spatial amplitude such as
a Hermite–Gaussian (HG) beam, spatial phase such as an
OAM beam, and spatial polarization such as a vector beam,
which can be generated by various schemes
[3–9]
. The com-
plex temporal waveforms include complex amplitude and
other special waveforms. The complex amplitude is well
known for advanced modulation formats such as M-ary
phase-shift keying (m-PSK) and M-ary quadrature ampli-
tude modulation (m-QAM)
[10]
. The tailored complex opti-
cal fields may find a wide variety of interesting applications
in optical manipulation, imaging, microscopy, quantum in-
formation processing, and optical communications on dif-
ferent platforms of waveguides, free space, and fiber
[11–16]
.
In this Review, we focus on data information transfer
using complex optical fields in waveguides, free space,
and fiber.
Taking an OAM beam as one example of complex
optical fields, as shown in Fig.
3, the typical data informa-
tion transfer approaches include modulation, multiplex-
ing, and multicasting. Modulation employs different
orthogonal OAM states to encode data information
which is similar to the widely used complex amplitude
modulation (e.g., m-PSK, m-QAM). Multiplexing adopts
different OAM beams as orthogonal carriers to deliver and
combine multi-channel data information. Multicasting
duplicates data information into multiple copies for multi-
ple end users (i.e., one-to-many communications).
Remarkably, not only OAM beams but other complex op-
tical fields can be used for data information transfer by
modulation, multiplexing, and multicasting.
First, we discuss complex optical field modulation for
data information transfer.
The complex amplitude modulation, has been not only
widely used in long-haul optical fiber communications
[17]
,
but applied to metro/access and data center applica-
tions
[18,19]
. Moreover, chip-scale optical interconnects have
also employe d complex amplitude modulati on for data
information transfer
[20–22]
. Here one example is shown of
chip-scale data information transfer in a compact silicon
microring using orthogonal frequency-division multiplex-
ing based on offset QAM (OFDM/OQAM), which is
modulated with a 256-QAM. Figure
4 shows scanning
electron mi croscope (SEM) images of a fabricated silicon
microring. We demonstrate chip-scale data information
Fig. 1. Multiple physical dimensions of photons and twisted
light carrying OAM.
COL 15(3), 030005(2017) CHINESE OPTICS LETTERS March 10, 2017
1671-7694/2017/030005(5) 030005-1 © 2017 Chinese Optics Letters