A hybrid U-shaped-microbend fiber optic evanescent wave sensor was developed by combining two types
of bending structures on the optical communication single mode optical fiber (SMF28). To study the
effect optical microbending on the output power, corrugated plates consisted of cylindrical structured
surface with various distance between the glass rods of 6 cm, 12 cm and 18 cm were constructed. The
macrobending effect was introduced by bending the SMF into two shapes, namely U-shaped and Sshaped. The bare SMF with various bending designs were immersed into numerous water sources from
Sg. Simin, Sg. Batang Benar and Sg. Klang. The output demonstrated that Sg. Simin was the most
polluted river, followed by Sg. Klang and Sg. Batang Benar using U-shaped microbend SMF with
distance between glass rod of 6cm and 1310 nm laser source. This result showed an excellent agreement
with water quality index (WQI) data released by the Department of Environment (DOE), Malaysia.
Maximum optical output power was obtained by using Sg. Simin’s water sample due to better light
absorption from the evanescent waves by the pollutant particles, that avoided light leakage in comparison
with less polluted water sources. The optimum sensing performance was successfully resulted by using
U-shaped SMF due to its durability and uniform evanescent waves radiated from the cladding. In
conclusion, the hybrid U-shaped-microbend SMF sensor based on evanescent waves propagation portrays
an excellent potential to detect water pollution by monitoring the presence of pollutants around the fiber
This paper reports the effect of microbending losses in single mode optical fiber
for pressure sensing system application. Several types of periodical corrugated
plates were fabricated, namely cylindrical-structured surface (Plate A) and
rectangular-structured surface (Plate B) with thicknesses of corrugated parts
were varied at 0.1 cm, 0.2 cm and 0.3 cm. Laser sources with excitation
wavelengths of 1= 1310 nm and 2= 1550 nm were launched at the first end
of the fiber. The values of losses were recorded by using an optical power
meter. It was clearly seen that the microbending losses were polynomially
increased with the increment of applied pressure and the thicknesses of
corrugated parts of Plate A and Plate B. The maximum microbending losses of
1.5185 dBm/kPa was resulted as SMF was coupled with corrugated plates B
with thicknesses of 0.3cm by using excitation wavelength of 1550nm. These
values reduced to 0.7628 dBm/kPa and 0.4014 dBm/kPa as the thicknesses
were decreased to 0.2cm and 0.1cm respectively. In comparison with a plain
plate which acted as a reference indicator, the maximum percentage of
microbending losses was obtained as 74.29 % for Plate A and 95.02 % for Plate
B. In conclusions, we successfully proved the ability of SMF as a pressure sensor
by manipulating the microbending losses experienced by the fiber. The
employment of 1550nm of laser wavelength results better sensitivity sensor
where the system able to detect large losses as the pressure applied on the
corrugated surfaces.
With the increasing demand for greater quality of transferred data, the optical cable
lines are reaching their limits of transfer capacities. The alternative for more effective
usage is by introducing the Dense Wavelength Division Multiplexing (DWDM)
integrated with optical amplifier to optimize the output signal. This study was
performed theoretically with an assistance of OptiSystem 9.0 simulation software to
develop higher transfer speed of 32 channels DWDM network system by employing
hybrid optical amplifiers. Three types of optical amplifiers had been introduced such
as Erbium Doped Fiber Amplifier (EDFA), Semiconductor Optical Amplifier (SOA) and
Dynamic RAMAN amplifier. The optimum performance of DWDM system was obtained
by employed hybrid EDFA-Raman amplifier which resulted the best transmission signal
received with maximum Qfactor=43.0579 a.u. The hybrid EDFA-Raman produced
better stability than EDFA-SOA where the received signals were only fluctuated within
±3.73 a.u. In comparison with other types of configuration, namely EDFA-SOA and
RAMAN-SOA; the value of maximum Q-factor experienced about 50% of increment. In
conclusion, the development of high performance and excellent stability of 32-
channels DWDM optical network system can be achieved by introduced hybrid
amplifier of EDFA-RAMAN.