ahmad Zamzuri

Tapered-EDF-Based Mach–Zehnder Interferometer for Dual-Wavelength Fiber Laser

An all-fiber comb filter using a tapered-erbium-doped fiber in a Mach-Zehnder interferometer structure is presented. The free spectral range, extinction ratio, bandwidth, and interference pattern of the comb filter can be shaped by controlling the taper waist length and the length of up and down taper transition regions. By varying the taper waist length from 5 to 25 mm, the free spectral range changes from 14.7 to 1.0 nm, and the linewidth varies from 3.3 to 0.3 nm, respectively. We demonstrate a tunable dual-wavelength laser by using the tapered-erbium-doped fiber as a gain medium as well as a wavelength-selective element. The laser can be tuned at a resolution of 0.2 nm with a side-mode suppression ratio of up to 46.88 dB and a linewidth of 0.09 nm.

Experimental validation of double-pass discrete Raman amplifier limitation for large signals

In this letter, we present a report on the experimental validation of double-pass discrete Raman amplifier (DRA) limitation for large signals. It has been proven that the limitation of double-pass Raman amplifier for large signals is due to stimulated Brillouin scattering (SBS) even though with a modulated signal at 10-Gb/s data. The multichannel amplification shows that this limitation can be relaxed due to energy distribution among the channels, the SBS threshold is enhanced. An average gain of 19.2 dB is obtained in four-channel amplification without any significant SBS effects. The double-pass DRA is found suitable for large signals to be deployed in wavelength division multiplexing systems

Characterization of tapered-erbium doped fiber in co-propagating amplifier

The characteristics of tapered-EDF is studied. The loss, transmission and ASE spectrum, gain and noise figure are measured in order to observe the behavior of tapered-EDF. The comb-like spectrum with equal distance of 1.6nm is observed both for the ASE spectrum as well as for the transmission spectrum. This validates that the coupling between fundamental mode and higher order modes occurred in the tapered section. The power intensity loss is 7 dB due to tapering process. Due to that fact, the gain and noise figure does not show significance improvement in the experiment.

Gain-control hybrid Raman fiber amplifier/EDFA incorporating ring cavity with a single pump source

All-optical gain-control Raman fiber amplifier (RFA) based on ring cavity technique using a pair of circulators is investigated experimentally. A pair of 1465nm laser diodes is used as the pump source to the RFA which provides a gain peak at around 1565 nm. The analyses of gain and noise figure are carried out using lasing wavelengths of 1550 and 1565 nm. Gain and noise figure variations are 0.4 and 0.5 dB respectively. We observed strong influence of pump-signal relative intensity noise transfer that results in noise figure penalty. The analyses are also carried out on hybrid configuration of RFA and EDFA and the characteristics of the dynamic range of the configurations are being compared.

Experimental validation of double-pass amplification in discrete Raman amplifier

This report is presented to validate the double-pass amplification characteristics in discrete Raman. The double-pass discrete Raman amplifier (DRA) based on dispersion compensating fiber (DCF) and high reflection fiber Bragg grating (FBG) at pump wavelength is constructed with the pump light at 1435 nm launched in counter-directional to the incoming input signal. The double-pass direction of the signal is achieved through a fiber loop mirror constructed by a circulator. From the experimental result, we show that this design is mostly suitable for small signal region. The small signal input regime from -40 dBm up to -10 dBm will benefit from the high-gain and low-noise characteristics of double-pass design. It is observed that, the maximum of 22 dB gain is achieved with the noise figure maintained at less than 5 dB.

Double pass Discrete Raman Amplifier with FBG for pump power Optimization and Improved Performance

We present a report on the experimental validation of double-pass discrete Raman amplifier based on dispersion compensating fiber and high reflection fiber Bragg grating at pump wavelength. The pump light at 1435 nm is launched in counter-directional to the incoming input signal. The double-pass direction of the signal is achieved through a fiber loop mirror constructed by a circulator. We proved that with the proposed design, it requires only 55% of the pump power to achieve the same Raman gain compared to the typical single-pass Raman amplifier.