Investigation on the pre-compensation and
post-compensation cascaded multi-channel-chirped fiber
Bragg gratings for a repeaterless transmission system
K. Khairi
1,2,
*, H. Fong Kok
1
, Z. Lambak
1
, M. I. Abdan
1
, M. A. Farhan
1
, M. H. Othman
1
,
M. L. H. Jamaluddin
1
, S. A. Mohamad Rofie
1
, Tee Din Chai
1
, K. Chia Ching
1
,
A. Mohd. Ramli
1
, M. A. Mokhtar
1
, S. A. Syed Ahmad
1
, M. Mokhtar
2
,
S. B. Ahmad Anas
2
, and M. A. Mahdi
2
1
TM Research & Development Sdn. Bhd., Lingkaran Teknokrat Timur, 63000 Cyberjaya, Selangor, Malaysia
2
Wireless and Photonics Network Research Center, Department of Computer & Communication Systems Engineering,
Faculty of Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
*Corresponding author: kharina@tmrnd.com.my
Received December 18, 2017; accepted February 28, 2018; posted online March 26, 2018
We experimentally designed dispersion-managed repeaterless transmission systems with a pre-compensation and
post-compensation technique using multi-channel-chirped fiber Bragg gratings. The repeaterless transmission
link supports a single channel (1548.51 nm) with a 10 Gbps repeaterless transmission system over 300 km
standard single-mode fiber (SSMF). In the system design, two distributed Raman amplifiers (DRAs) wer e
used to improve the signal level propagated along the 300 km SSMF. The co-propagating DRA provided
15 dB on–off gain and the counter-propagating produced 32 dB on–off gain at the signal wavelength. T he
experiment results show that the post-compensation configuration achiev es an optimal performance wit h
a bit error rate at 1 × 10
−9
.
OCIS codes: 060.2330, 060.4510.
doi: 10.3788/COL201816.040607.
A repeaterless transmission syste m is the best solution for
high speed data transmission, particularly in submarine
applications. The system is designed without repeaters be-
tween transmitting and receiving stations over several
hundred kilometers (km) of fiber optics cable (FOC)
and, therefore, provides a simple and cost-effective solu-
tion. Such tremendous improvements on a submarine re-
peaterless system
[1–4]
are attractive towards terrestrial
applications that require fast deployment with less opera-
tional expenditure, as well as capital expenditure. Some
examples are rural or suburban broadband deployment,
where maintenance access is either limited, difficult, or
both. Even though the bandwidth requirement is low in
such areas, with an established infrastructure and internet
connectivity, the costs of broadband deployment can be
reduced, thus narrowing the digital divide.
Recent repeaterless systems showed tremendous works
with an adoption of a high speed bit rate, equipped with
coherent technologies as well as an advanced amplification
scheme, such as a remote optically pump amplifier (ROPA).
The systems extend over 500 km transmission fiber with
terabits speed
[5–7]
. However, such designs are complex with
high cost investment, which is appropriate for high popula-
tion areas or city centers that are linked to economic activ-
ities with higher utilization of broadband internet.
There are also limitations in a repeaterless transmission
system, such as fiber loss, chromatic dispersion (CD), and
nonlinearity effects, which, in turn, limit the maximum
transmission distance and contribute to inter-symbol
interference (ISI). As a repeaterless transmission system
is designed for 10 Gbps bit rate and above, the effects from
both dispersion and nonlinearity are dominant due to high
power and large signal bandwidth
[8–12]
. To overcome this
limitation, a dispersion compensation module (DCM) is
mandatory in optical transmission networks. Two popular
methods of CD compensation that are commercially
used and are currently available in the market are disper-
sion compensation fiber (DCF) and chirped fiber Bragg
gratings (CFBG).
In a long-haul transmission, the nonlinearity effects also
accumulate with distance. The accumulation of nonlinearity
effects becoming sturdier results in the inability of the signal
pulse to be reshaped through linear compensation. In addi-
tion, high power intensity as well as a higher bit rate also
worsens the effects of nonlinearity. The nonlinearity effects
result in the change of the refractive index followed by phase
modification, which, in turn, broadens the signal. The limi-
tation is overcome by locating the DCM in the transmission
network. Several solutions are available, such as pre-compen-
sation, post-compensation, as well as mixed-compensation
(pre-compensation and post-compensation)
[13]
.
Recent study on DCM management conducted by
Yusoff et al.
[14]
investigated the composition of DCM
using an L-band CFBG over 90 km SMF. Khairi et al.
[15]
conducted a similar investigation using a multi-channel
CFBG (MC-CFBG) over 100 km. The findings demon-
strated that pre-compensation configuration obtained
an optimal bit error rate (BER) performance against
COL 16(4), 040607(2018) CHINESE OPTICS LETTERS April 10, 2018
1671-7694/2018/040607(6) 040607-1 © 2018 Chinese Optics Letters