A.A. Latif

Graphene-Based Saturable Absorber for Single-Longitudinal-Mode Operation of Highly Doped Erbium-Doped Fiber Laser

In this paper, a conventional wavelength band (C-band) fiber laser with a tunable single-longitudinal-mode (SLM) output using multilayer graphene as a saturable absorber is demonstrated. The proposed fiber laser uses a short length of highly doped erbium-doped fiber (EDF) as the gain medium and a fiber ferrule with graphene flakes adhered to it by index matching gel (IMG) that acts as the saturable absorber. The fiber laser is able to generate an adjustable wavelength output between 1547.88 and 1559.88 nm with an average peak power of -6.48 dBm with a measured signal-to-noise ratio between 66.0 and 68.3 dB. The SLM output is verified by the absence of frequency beating in the radio frequency (RF) spectrum output and by a measured linewidth of 206.25 kHz using the self-heterodyne technique. The deposition of graphene flakes on the fiber ferrule using the IMG is a new and effective technique to generate SLM operation in the fiber laser.

17-channels S band multiwavelength Brillouin/Erbium Fiber Laser co-pump with Raman source

In this paper, we propose and demonstrate a stable Brillouin-Erbium Fibre Laser (BEFL) capable of generating up to 17 lasing wavelengths in the Short-Wave length (S-band) region. The proposed setup uses a 7.7 km Dispersion Compensating Fibre (DCF) to act as a non-linear gain medium and a 30 m long Depressed-Cladding Erbium Doped Fibre (DC-EDF) as an optical amplifier for amplification in the S-band region. The proposed BEFL has an optimum tuning range of 1499 to 1502 nm and is capable of generating 17 lasing wavelengths with peak powers of between −20 to −15 dBm when injected with a Brillouin Pump (BP) of 5 dBm at 1499 nm and a Raman Pump (RP) of 300 mW at 1420 nm.

A simple linear cavity dual-wavelength fiber laser using AWG as wavelength selective mechanism

In this paper, a simple design of linear cavity dual-wavelength fiber laser (DWFL) is proposed. Operating in the C-band region stretching from 1538.3 nm to 1548.6 nm, an arrayed waveguide grating (AWG) is used to generate the dual-wavelengths output together with a broadband fiber Bragg grating as a back reflector and an optical circulator with a 10% output coupling ratio which acts as a front mirror. The measured average output power of the DWFL is about −5.66 dBm and with a side mode suppression ratio (SMSR) of 53.1 dB. The spacing between the two output wavelengths can be varied from 0.8 nm to 10.3 nm with a stable output and minimum power fluctuations.

Tunable single longitudinal mode S-band fiber laser using a 3 m length of erbium-doped fiber

In this paper a tunable single-longitudinal mode (SLM), short-wavelength band (S-band) fiber laser using a conventional erbium-doped fiber (EDF) with a length of 3 m and a step index erbium dopant profile as opposed to the commonly used depressed cladding erbium-doped fiber (DC-EDF) is proposed and demonstrated. The proposed SLM fiber laser has a tuning range of 1496 to 1507 nm in a ring configuration using two 0.15 m of EDF which acts as saturable absorbers (SAs). The highest peak power measured is about −0.6 dBm at a wavelength range of 1502 to 1507 nm. The measured signal-to-noise ratio (SNR) is approximately 74 dB for the same wavelength range. The line-width of the SLM output is measured to be 140 kHz.

Tunable high power fiber laser using an AWG as the tuning element

In this paper, a design of a High Power Tunable Fiber Laser (HP-TFL) in C-band region from 1536.7 to 1548.6 nm is set forth with Erbium Doped Fibers (EDFs) being used as a seeding signal and a booster amplifier. With a 1 × 16 channels Arrayed Waveguide Grating (AWG), this setup is capable of generating 16 different wavelengths with an average output power of 20.7 dBm.

Highly stable graphene-assisted tunable dual-wavelength erbium-doped fiber laser

A highly stable tunable dual-wavelength fiber laser (TDWFL) using graphene as a means to generate a highly stable output is proposed and generated. The TDWFL comprises a 1 m long, highly doped erbium-doped fiber (EDF) acting as the linear gain medium, with a 24-channel arrayed waveguide grating acting as a wavelength slicer as well as a tuning mechanism to generate different wavelength pairs. The tuned wavelength pairs can range from 0.8 to 18.2 nm. A few layers of graphene are incorporated into the laser cavity to induce the four-wave-mixing effect, which stabilizes the dual-wavelength output by suppressing the mode competition that arises as a result of homogenous broadening in the EDF.

Dual wavelength fibre laser with tunable channel spacing using an SOA and dual AWGs

In this paper, we propose and demonstrate a dual wavelength fibre laser (DWFL) based on the use of an inhomogeneously-broadened semiconductor optical amplifier (SOA) gain medium as well as two arrayed waveguide gratings (AWGs) together with two optical channel selectors (OCSs) and a broadband fibre Bragg grating (FBG) to generate dual wavelength output at variable channel spacings. The widest spacing obtained from the DWFL is 12.21 nm, while the narrowest spacing is 1.16 nm. The DWFL has good stability with only minor power fluctuations of less than 2 dB and a side mode suppression ratio (SMSR) of approximately 38.5 dB with fluctuations of less than 0.5 dB.

Controllable Wavelength Channels for Multiwavelength Brillouin Bismuth/Erbium Based Fiber Laser

We propose and demonstrate a Multiwavelength Brillouin Bismuth/Erbium Fibre Laser (MBBEFL) with the ability to control the number of wavelength channels generated. A multi-wavelength comb output is obtained using a 7.7km DCF as a non linear gain medium to generate Stokes wavelengths through the process of Stimulated Brillouin Scattering (SBS). The DCF is pumped by a Raman pump source at 400mW to lower the dispersion loss and promote the generation of the Stokes wavelengths. A 49cm long Bismuth based Erbium Doped Fibre (Bi-EDF) is used as an optical amplifier to provide the necessary gain for the Brillouin Pump and also act as the gain medium for the generated Stokes signal.

High gain S-band semiconductors optical amplifier with double-pass configuration

In this paper we propose and demonstrate a double-pass configuration of a compact high gain short wavelength (S-) band amplifier based on a semiconductor optical amplifier (SOA) operating from 1480 to 1520 nm. The proposed system provides gain value of 31.07 dB at a signal power level of −40 dBm taken at 1500 nm. The measure gain profile of the double-pass configuration over different power levels and at different signal wavelengths outperforms that of the single-pass configuration. The noise figure of both configurations averages out to 10 dB. This system provides a good alternative as a high-gain and compact amplifier in the S-band region.

Wavelength conversion based on FWM in a HNLF by using a tunable dual-wavelength erbium doped fibre laser source

In this paper, we propose and demonstrate a cost-effective wavelength converter utilising a highly nonlinear fibre (HNLF) and a tunable dual-wavelength fibre laser as the pump source. The proposed system uses only the pump source and a signal probe to generate a partially degenerate four-wave mixing (FWM) effect. An FWM conversion efficiency of −12 dB is obtained at pump and signal powers at +13.3 dBm and +5 dBm, respectively, and it is predicted that a higher conversion efficiency is possible if a high power dual-wavelength fibre laser source is used.