N.A. Awang

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 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.

FIBER LOOP MIRROR FILTER WITH TWO-STAGE HIGH BIREFRINGENCE FIBERS

A flber loop mirror (FLM) with two-stage high birefrin- gence (Hi-Bi) flbers is theoretically and experimentally studied for var- ious rotation angles and Hi-Bi flber lengths. The experimental spectra are observed to be in good agreement with the theoretical spectra, ver- ifying our theoretical model. The wavelength interval of the comb fllter depends on the Hi-Bi flber lengths and rotation angles. By varying the rotation angle from 0 - to 90 - , a comb-like transmission spectrum with small wavelength spacing is evolving into an exotic but periodic trans- mission spectrum and eventually become a larger wavelength spacing transmission spectrum. The FLM is useful in many applications such wavelength division multiplexing power equalization and management, switchable multi-wavelength flber laser, optical switch and etc.

Temperature Sensing Using Frequency Beating Technique From Single-Longitudinal Mode Fiber Laser

In this paper, a high-resolution fiber temperature sensor is proposed and demonstrated using the frequency beating technique. The sensor uses a constant wavelength (CW) at 1539.96 nm as the reference signal for the frequency beating technique. The sensor signal is provided by a fiber Bragg grating (FBG) tuned single-longitudinal mode (SLM) fiber laser, which consists of a 0.5-m long highly doped Zirconium-Erbium doped with an erbium concentration of 3000 ppm as the gain medium. The signal of the SLM, which is generated by the FBG in response to external temperature changes, is mixed with the CW signal using a 3-dB fused coupler into a 6-GHz photodetector to generate frequency beating. The typical response of the system is about 1.3 GHz/°C, with nominal temperature measurement resolutions of 0.0023°C being achieved, taking into account the resolution bandwidth of 3 MHz of the radio frequency spectrum analyzer.

Stable zirconia-erbium doped multiwavelength fiber laser by precise control of polarization states

A compact zirconium-erbium doped fiber (Zr-EDF) based multiwavelength fiber laser (MWFL) with stable output comb is proposed and demonstrated. The MWFL utilizes a 3 m long Zr-EDF with an erbium concentration of 3000 ppm and pumped by a 1480 nm laser diode (LD) as the active gain medium. A fiber based multimode polarization controller (PC) is used to precisely control the polarization states of the oscillating modes in the MWFL, distributing the total energy of the system among the lasing wavelengths in order to overcome the mode-suppression and mode-competition that arises from homogenous line broadening. The MWFL is capable of generating up to four lasing wavelengths with average peak powers of 0.08 dBm in the extended L-band of 1600 nm. The lasing wavelengths have a 3-dB linewidth of 0.1 and an extinction ratio of 40 dB as well as highly stable, with minimal fluctuations of less than 0.6 dB observed in the peak powers of the lasing wavelengths over a period of 1 h. The proposed system allows for the realization of a compact, cost-effective and stable erbium based MWFL capable of operating at room temperature.

O-band to C-band wavelength converter by using four-wave mixing effect in 1310 nm SOA

In this paper we provide a detailed account of an ultra-wideband wavelength converter that shifts from 1310 to 1550 nm using a 1310 nm semiconductor optical amplifier as the nonlinear medium. The experimental approach uses an arrayed waveguide grating (AWG) as a method to slice the broadband output ASE of the 1310 nm SOA into multiple outputs at this O-band. A four-wave mixing technique is used to generate the wavelength conversion, whereby two wavelengths at 1310 nm are used and interact with the 1550 nm continuous wave output from a bismuth-based erbium-doped optical amplifier. In this demonstration, the interacting wavelengths are 1316.75, 1317.47 and 1542.21 nm. The downward conversion wavelengths are 1542.93 and 1541.49 nm, with a converted wavelength spacing of 224 nm.

Highly efficient and high output power of erbium doped fiber laser in a linear cavity configuration

A simple Erbium Doped Fiber Laser (EDFL) in linear cavity configuration is reported. The cavity design is based on an FBG as a back reflector, and a loop back optical circulator with an output coupler as the front reflector. Different coupling ratios of the coupler are tested and 50: 50 provides the highest coupling output power of 22.06 dBm (160.7 mW). The pump power conversion efficiency is about 95% when pumping with two pump lasers at 1460 and 1490 nm with combined pumping power of 545 mW. The laser output has a measured linewidth of 0.0179 nm.

Enhancement of four wave mixing characteristic in Semiconductor Optical Amplifier using Fiber loop mirror

We investigate the effect of the input wave power, wavelength detunes between the two source waves and the conjugate wave power to conversion efficiency. The essential part of the investigation is about suppression ratio of pump power and conjugated wave power. The proposed setup success for suppress the pump power and increase the conjugate signal in wavelength detuning of 1.4 nm. It is due to loop mirror that act as a reflector where depend to the high birefringence of the Polarization Maintaining Fiber (PMF) and the polarization controller.