Ahmad Atieh

Measuring the Raman time constant (T/sub R/) for soliton pulses in standard single-mode fiber

The Raman time constant (T/sub R/) used in the generalized nonlinear Schrodinger equation is determined experimentally at 1550 nm based on the Raman self-frequency shift in a standard single-mode fiber. The effective value of the T/sub R/ as measured is found to be 3.0 fs. Detailed error analysis shows that the uncertainty in the measurement is less than /spl plusmn/1.0 fs. The measured value of the T/sub R/ is approximately half of what is commonly used at present in theoretical simulations. Determined experimentally in this work the accurate value of T/sub R/=3.0 fs is essential in modeling pulse propagation in optical fibers.

Generation of multigigahertz bright and dark soliton pulse trains

Abstract A comprehensive study for generating trains of ultra-high speed bright and dark soliton pulses at 1553 nm using comblike dispersion profile fiber structures is presented. The comblike structure employed for generating bright solitons uses the lowest average power for the input signal ever reported. The generated bright soliton pulses have a full width at half maximum (FWHM) of 2.2 ps at a repetition rate of 49.3 GHz, while the generated dark soliton pulses have a FWHM of 3.8 ps at 47.6 GHz. The experimental results agree well with performed numerical simulations.

Scheme for measuring dispersion of chirped FBG using loop mirror configuration

A novel scheme for measuring dispersion of chirped fiber Bragg gratings is demonstrated using loop mirror configuration. The measurement is insensitive to polarization or temperature variation. The technique is relatively simple, inexpensive, and requires only a broad-band light source.

Demonstration of all-optical demultiplexing of a multilevel soliton signal employing soliton decomposition and self-frequency shift

We report an experimental demonstration of an all optical demultiplexing a burst of 4/spl times/10-Gb/s multilevel TDM soliton signal using the soliton effect pulse compression and soliton self-frequency shift in a silica fiber.

Partial bit delay correlative modulation used to improve the dispersion tolerance of an optical duobinary system

Phase effect of the optical duobinary (ODB) modulation on the chromatic dispersion (CD) tolerance is more important than the ODB modulation-induced bandwidth effect. To show this, we evaluate, respectively, the filter bandwidth effect and the phase effect of the partial bit delay correlative modulation (PBDCM) on the CD tolerance. Due to the cancellation between the CD-induced and the PBDCM-induced phase effects, the PBDCM method can increase the CD-limited transmission to 2 ??? 3 times of that using standard 1-bit delay modulation, while the optimized filter bandwidth method can increase the transmission by 50% or less, depending on the input signal format. The PBDCM can be physically realized by adjusting the delay time of the delay-and-add circuit in the conventional duobinary transmitter (without lower-pass filter). These conclusions are also valid for systems having non-negligible polarization-mode dispersion (PMD) and polarization dependent loss (PDL).

Design and Performance of an All-Optical Wavelength Converter Based on a Semiconductor Optical Amplifier and Delay Interferometer

The design and performance of an all-optical wavelength converter based on a semiconductor optical amplifier (SOA) and a delay interferometer (DI) are presented for 10-Gb/s return-to-zero (RZ) transmission systems with pulsewidths of 25-45 ps. The performance of the wavelength converter is investigated in terms of the operating conditions for the SOA and DI, and the properties of the input signal. The regenerative characteristics of the wavelength converter are also examined for input signals degraded by amplified spontaneous emission noise and residual dispersion. With proper design, the SOA-DI structure provides a high-performance all-optical wavelength converter for 10-Gb/s RZ transmission with practical pulsewidths.

Loop Erbium-Doped Fiber Amplifiers

A comprehensive study of implementing erbium-doped fiber amplifiers (EDFAs) using a loop configuration is presented. Two different schemes based on the mechanism of directing the loop output are investigated. The amplified spontaneous emission at the output port is 3 dB lower than conventional designs. This configuration is recommended for high-power EDFAs.A comprehensive study of implementing erbium-doped fiber amplifiers (EDFAs) using a loop configuration is presented. Two different schemes based on the mechanism of directing the loop output are investigated. The amplified spontaneous emission at the output port is 3 dB lower than conventional designs. This configuration is recommended for high-power EDFAs.

The effect of batteries DOD range setting values on diesel engine generator pollution and overall cost of a hybrid solar/diesel/battery system

Depending on applied criteria, sizing optimization process of renewable energy plants produces different optimal dimensions of the system components. This work presents a sizing algorithm of hybrid solar/diesel/battery system; where the battery depth of discharge (DOD) range setting is considered as a key to guarantee low overall system cost and minimum CO2 emission. Different DOD range setting values (0–80%, 20–80% and 40–80%) are used in the investigation in order to ensure minimization adequacy between overall system cost and pollution emission. Obtained results show that CO2 emission and system cost are sensitive for DOD setting range. Following a juxtaposition of pollution rate and system cost curves function of DOD range set values, an optimum operating point is obtained which consists of a DOD range set value of 22–80%.

Novel multilayer structure CWDM demultiplexer in silica

Novel CWDM multilayer structure demultiplexer in silica is proposed and investigated. The refractive index of each layer in the structure follows fiber graded index profile with a-parameter less than one. The demultiplexer structure depends on the refractive index profile parameter, thickness, incidence angle, number of layers and channels spacing. The effect of all of these parameters on the amount of spatial shift and the separation between adjacent channels is investigated.

In Service Cumulative Optical Fiber Chromatic Dispersion Monitoring

Simple and relatively inexpensive in service optical fiber chromatic dispersion monitoring is demonstrated using supervisory channel. Modulating optical supervisory channel with frequency in the range of hundreds of MHz enables accurate measurement for lengths up to 80 km of SMF-28 fiber.