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Microring Resonator (MRR) system is utilized to generate comb signal including eight carriers, owing 10 GHz free spectral range (FSR) to be applied in wavelength-division multiplexing (WDM) systems. Applying multiband (MB) approach, the ultra-high spectral effective orthogonal frequency-division multiplexing (OFDM) technology is utilized to modulate each of the simulated multicarrier and by taking advantage of the dual polarization (DP) technique the high data rate of 236.8 Gb/s MB-DP-OFDM signal is achieved. The MB-DP-OFDM signal is transmitted through 50 km single mode fiber (SMF) and received by the coherent receiver. The system’s performance was assessed by using the bit error rate (BER) of the system, where the BER of 2 × 10 −3 was achieved. [ABSTRACT FROM AUTHOR]

Single longitudinal mode (SLM) erbium-doped fiber (EDF) laser operation using a commercialized ultra-narrow bandwidth optical filter has been demonstrated. A 2-m long EDF with an absorption coefficient of 24 dB m −1 at the pump wavelength is used as gain medium. The ultra-narrow tunable filter is used for selection of a single longitudinal mode from the available spectrum of multiple modes, which originally exist in the FBG's reflection spectrum. Our approach provides a relatively simple and direct method for realization of SLM operation. A high-resolution optical spectral analyser with a resolution of 0.16 pm is used to observe the output spectrum. To verify the SLM operation, the delayed self-heterodyne method is used, giving a measured laser linewidth of 61.5 kHz. [ABSTRACT FROM AUTHOR]

A semiconductor optical amplifier (SOA) based linear cavity L-band dual wavelength fiber laser (DWFL) with a switchable output is proposed and its operation demonstrated. The DWFL is configured as a linear cavity, with a 1 × 24 arrayed waveguide grating together with two optical switches providing channel spacing tunability. An L-band SOA, with a central operating wavelength of 1580 nm and an operation bandwidth of 1500–1640 nm serves as the gain medium of the proposed laser cavity. The DWFL is able to generate a dual-wavelength output, with the widest spacing obtained being 18.7 nm and the narrowest spacing being 0.8 nm. The generated output is highly stable, with only minor power fluctuations of less than 2 dB as well as having a signal-to-noise ratio of 42 dB. The proposed setup would have numerous uses, particularly for sensor applications. [ABSTRACT FROM AUTHOR]

Abstract A passively Q-switched thulium/holmium fiber laser with a gallium selenide (GaSe) saturable absorber (SA) is proposed and demonstrated for the first time. The GaSe based SA is prepared by mechanical exfoliation and inserted into the proposed laser cavity to generate Q-switched pulses. Stable Q-switching operation is achieved at 1986.0 nm, with output pulse repetition rates ranging from 22.9 kHz to 32.3 kHz over a pump power range of 112.0 mW to 235.0 mW. The generated Q-switched pulses have a maximum pulse energy of 120.3 nJ and minimum pulse width of 6.9 μs. The proposed thulium/holmium fiber laser with GaSe SA will be able to cater to multiple applications requiring pulsed laser outputs in the 2.0 μm region. [ABSTRACT FROM AUTHOR]

A simple relative humidity (RH) sensor based on a tapered single mode fiber loop resonator (MLR) is proposed and experimentally verified. The refractive index of the microfiber in the MLR was modified by environmental humidity, and its emission wavelength changed with RH level. Reduced graphene oxide (rGO) material was used for this device due to its inherent characteristics of high water permeability and high sensitivity whereby long response and recovery times are reduced. Moreover, humidity sensors have been widely used in different fields and are used in the solutions of numerous problems. The performance of tapered fiber was measured with and without rGO and at fiber diameter of 4.04 μm. The spectrum was observed to shift with the wavelength as relative humidity increased, and measured sensitivity with rGO was 0.0537 nm/%RH and without rGO was 0.0316 nm/%RH in the range of 30 to 50% relative humidity. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a novel configuration of a wavelength converter is set forth by utilizing a semiconductor optical amplifier (SOA) as a nonlinear gain medium to generate a four-wave mixing (FWM) effect by using a dual wavelength bi-erbium-doped fiber laser that uses an Arrayed Waveguide Grating (AWG) together with two optical channel selector (OSC) as selective elements to function as a dual wavelength switchable pump power. The four-wave mixing (FWM) is produced with a wavelength detuning of 7nm from the pump and signal which used is as the converted signal at wavelength 1532.8nm or 1534.5nm for transferring data from the input signal at wavelength 1547.0nm. Thus, even though the conversion efficiency is as low as −43dB, it is still possible for applications as a wavelength converter. [Copyright &y& Elsevier]