Multiwavelength Fiber Laser Research Articles

Nanostructured LNTO saturable absorber for generating multi-wavelength laser in Q-switched EDFL

In this paper, we propose a new and efficient ferroelectric nanostructure metal oxide lithium niobate [(Li1.075Nb0.625Ti0.45O3), (LNTO)] solid film as a saturable absorber (SA) for modulating passive Q-switched erbium-doped fiber laser (EDFL). The SA is fabricated as a nanocomposite solid film by the drop-casting process in which the LNTO is planted within polyvinylidene fluoride-trifluoroethylene [P(VDF-TrFE)] as host copolymer. The optical and physical characteristics of the solid film are experimentally established. The SA is incorporated within the cavity of EDFL to examine its capability for producing multi-wavelength laser. The experimental results proved that a multi-wavelength laser is produced, where stable four lines with central wavelengths at 1529.5, 1530.5, 1531.5, and 1532 nm are observed on the laser spectrum at 157 mW pumped power. Furthermore, at maximum available pumped power (157 mW), laser pulses are running with a rate of 178 kHz and pulse width of 2.64 μs. The output power of 3.7 mW is attained at pumped power of 157 mW. The result proved that the LNTO-SA could be a potential candidate for generating multi-wavelength passive Q-switched fiber laser pulses.

CORRIGENDUM

This article corrects the following: First published: 29 August 2024 | https://doi.org/10.11113/mjfas.v20n4.3813 S. Daud, M. I. A. Zaini, M. S. A. Aziz, and A. F. A. Noorden, "Generation of multiwavelength fibre laser based on erbium-doped fibre amplifier with Lyot filter," Malaysian Journal of Fundamental and Applied Sciences, vol. 20, pp. 378-384, 2024.https://doi.org/10.11113/mjfas.v20n2.3091 CORRIGENDUM: After thorough discussions with the editor and following an official correspondence, it was decided to make the following correction in the article. The name of the author has been corrected to accurately reflect the contributions, and the acknowledgments section has been updated to properly recognize the individuals and institutions that provided support. Allen Paul Davida, Suzairi Daudb,c,*, Abdul Hadi Sulaimana, Muhammad Ilham Ahmad Zainib, Muhammad Safwan Abd Azizb,c and Ahmad Fakhrurrazi Ahmad Noordend, "Generation of multiwavelength fibre laser based on erbium-doped fibre amplifier with Lyot filter," Malaysian Journal of Fundamental and Applied Sciences, vol. 20, pp. 378-384, 2024. a Institute of Power Engineering, Universiti Tenaga Nasional, Jalam IKRAM-UNITEN, 43000 Kajang, Selangor, Malaysiab Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysiac Laser Center, Ibnu Sina Institute for Scientific & Industrial Research, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysiad Department of Physics, Kulliyah of Science, International Islamic University Malaysia, Bandar Indera Mahkota, 25200 Kuantan, Pahang, Malaysia The acknowledgment for this published paper should be as follows: This work was supported by Universiti Tenaga Nasional through the BOLD Refresh Postdoctoral Fellowships under the project code of J510050002-IC-6 BOLD REFRESH 2025 and Universiti Teknologi Malaysia by UTM Encouragement Grant Vote No. Q.J130000.3854.31J54. The authors apologize for this error.

Spacing mode multi-wavelength erbium doped fiber laser based on a symmetrical long-period fiber grating

We present a multiwavelength erbium-doped fiber laser based on a symmetrical long-period fiber grating (LPFG) with tunable spacing mode between single lasing mode and multiwavelength spectra. The LPFG was manufactured using a thermal expansion technique using an LZM-100 glass processing system equipped with a CO2 laser, and it was used as a wavelength-selective filter (WSF) in the laser ring cavity. The laser can emit single, double, triple, quadruple, quintuple, or sextuple lines in the range from 1546 to 1563 nm, which can be tunable by controlling the radius of curvature of the LPFG in the range 0–0.2662 m −1. A minimal spacing mode of 1.92 nm was observed in the multiwavelength region; meanwhile, the fiber laser offers an average spacing mode of 6.945 nm between the multiwavelength region and the single emission. This laser has a 3 dB linewidth of 0.11 nm and a side mode suppression ratio (SMSR) of 55.56 dB. Finally, according to experimental results, the laser has high wavelength stability at room temperature for 88 min.

Tunable and switchable multi-wavelength mode-locked fiber lasers induced by an optimized hybrid mode-locked composite filtering effect.

A multi-wavelength mode-locked fiber laser can generate different wavelengths from a single laser cavity, offering potential as a dual-frequency comb and serving as an ideal light source for terahertz wave generation. We present an optimized hybrid mode-locked Er-doped fiber laser with flexible outputs: switchable and tunable dual-wavelength mode-locking, along with stable tri-wavelength mode-locking, which is achieved by introducing 0.69 m polarization-maintaining fiber and bent 200 m single-mode fiber to enhance intra-cavity birefringence and nonlinear effect to optimize the hybrid mode-locking effect, that is, build the composite filter effect. The dual-wavelength mode-locking not only covers a tunable wavelength range of 5 nm but also provides tunable wavelength intervals of 4-26 nm due to the composite filter effect. The formation dynamics of the tri-wavelength mode-locking can be switched either pair-by-pair or one-by-one. This approach enables the realization of wavelength interval tunable dual-wavelength mode-locking in mode-locked fiber lasers simply by introducing fiber without additional actions. Such a simple, compact fiber laser with tunable wavelength capabilities holds significant potential for diverse applications.

Polarization Influence on Er3+-Doped Multi-Wavelength Brillouin Fiber Laser Based on Fiber Loop Mirror

Polarization influences on the performance of multi-wavelength Brillouin Er3+-doped fiber laser are investigated by adjusting the polarization controller (PC) in the fiber loop mirror (FLM), where the linear laser cavity is composed of a fiber-tailed mirror and an FLM, and the stimulated Brillouin scattering (SBS) and the Er3+-doped fiber amplification (EDFA) simultaneously serve as the cavity gain. We realized 1–7 Brillouin laser lines by increasing the 980 nm pump power. For the first-order Brillouin laser, the signal–noise ratio (SNR) and optical intensity present a sinusoidal envelope; the conversion efficiency changes significantly from 0.56465 dBm/mw to 0.44975 dBm/mw by adjusting the ring’s angle in the PC; the first-order SBS thresholds are 20.4 mw, 36.1 mw and 28.5 mw at different angles θ2 = 36°, 276° and 300°, respectively; flatness between the two Brillouin lasers change obviously from 2.863 dB to 41.801 dB with different ring angles; the second-order Brillouin laser is suppressed and disappears finally at Δθ2 = −64° to −84° and 106°~136° angle variation. For the fifth-order Brillouin laser, the highest-order Brillouin laser line is seriously suppressed until it disappears at some angle variations similarly. The powers and wavelength stabilities for one-, three- and seven-wavelength Brillouin fiber lasers were measured in 1 h, and the obtained Er3+-doped multi-wavelength Brillouin fiber laser (MWBFL) worked stably during that time, but the stabilities become worse with higher SBS orders.

Spacing-adjustable and switchable multi-wavelength erbium-doped fiber laser using the filter of MMF–PMF–MMF based on PHB

Spacing-adjustable and switchable multi-wavelength erbium-doped fiber laser using the filter of MMF–PMF–MMF based on PHB

Octave spanning and flat-top supercontinuum generation in standard foundry-compatible process-made Ge–Sb–Se chalcogenide glass waveguide

We reported near octave-spanning supercontinuum generation in Ge28Sb12Se60 chalcogenide glass rib waveguides. The waveguides were fabricated using foundry-compatible deep ultra-violet lithography, followed by plasma etching. We demonstrated an average propagation loss of ∼1.3 dB/cm at the 1550 nm telecommunication wavelength. With dispersion engineering, optimizing waveguide geometry, and pumping by a multi-wavelength femtosecond soliton fiber laser, we achieved a flat-top supercontinuum generation spanning from 1290 to 2400 nm and beyond . It has a 3 dB bandwidth of 436 nm and a 20 dB bandwidth of more than 900 nm. The implementation of such waveguides provides a practical broadband light source solution for on-chip spectroscopy and sensing systems.

Michelson interferometer-based tunable multiwavelength thulium-doped fluoride fiber laser in S-band for 5 G networks

This work reported a multiwavelength thulium-doped fluoride fiber laser (TDFFL) for the S-band region using the Michelson interferometer as an optical filter. Michelson interferometer was utilized as a comb-like filter, whereas dispersion-compensated fiber (DCF) of 10 km length was used to increase the number of lasing lines and reduce mode competition. Approximately 61 lasing lines were achieved with a signal-to-noise ratio (SNR) of 40 dB in the wavelength region from 1501.36 to 1505.52 nm within 10 dB of maximum power. The stability of the multiwavelength fiber laser was also recorded for the time duration of two hours, and it was found that all lasing lines were stable and equally spaced at the free spectral range (FSR) of 0.07 nm. The variation in optical power was less than 0.5 dB; however, the wavelength shift was about 0.01 nm. Tunability of multiwavelength laser has also been observed up to the broader transmission span of 57 nm by incorporating the tunable band pass filter (TBPF). Moreover, FSR was observed to be tunable within the range of 0.02 to 0.14 nm by using the optical delay line (ODL) with a Michelson interferometer. Additionally, the proposed laser can generate frequency signals from 2.65 GHz to 18.54 GHz according to the obtained range of FSR.

Observation and all-optical manipulation of replica symmetry breaking dynamics in a multi-Stokes-involved Brillouin random fiber laser photonic system

In this paper, we propose and demonstrate an all-optical control of RSB transition in a multi-wavelength Brillouin random fiber laser (MWBRFL). Multi-order Stokes light components can be subsequently generated by increasing the power of the Erbium-doped fiber amplifier (EDFA) inside the MWBRFL, providing additional disorder as well as multiple Stokes-involved interplay. It essentially allows diversified laser mode landscapes with adjustable average mode lifetime and random mode density of the 1st order Stokes, which benefits the switching between replica symmetry breaking (RSB) and replica symmetry (RS) states in an optically controlled manner. Results show that the average mode lifetime of the 1st order Stokes component gradually decreases from 250.0 ms to 1.2 ms as high orders from the 2nd to the 5th of Stokes components are activated. Meanwhile, the order parameter q of the 1st order Stokes random lasing emission presents distinct statistical distributions within the selective sub-window under various EDFA optical powers. Consequently, all-optical dynamical control of the 1st Stokes random laser mode landscapes with adjustable average mode lifetime turns out to be attainable, facilitating the RSB transition under an appropriate observation time window. These findings open a new avenue for exploring the underlying physical mechanisms behind the occurrence of the RSB phenomenon in photonic complex systems.

Generation of Multiwavelength Fibre Laser based on Erbium-Doped Fibre Amplifier with Lyot Filter

A ring cavity setup consisting of erbium-doped fibre amplifier (EDFA) as the optical pump and lyot filter aids in the production of a multiwavelength spectrum. The wavelength of EDFA pumps in photons range of 1530 nm to 1560 nm, respectively. Using maximum power of 18 dBm and a single mode fibre (SMF) of 10 km length, the number of peak lasing lines produced between 3 dB spectral range is 51. Tuning of the polarization controller (PC) to a specific angle helps provide the most stable lasing line. Stability test is done on the output multiwavelength fibre laser (MWFL) over a time period to analyze the wavelength stability.

High-order tunable multi-wavelength random Raman fiber laser based on few-mode fiber filter

In recent years, multi-wavelength fiber lasers have become one of the research hotspots and have been extensively applied in optical fiber communication systems. However, the presented multi-wavelength fiber lasers mainly operate in the 1.5 μm band. In this paper, a few-mode fiber filter-based cascaded high-order tunable multi-wavelength random Raman fiber laser (MWRRFL) is demonstrated, for the first time, in which a tuning range covers the 1.1–1.5 μm band. In the half-open MWRRFL, a few-mode fiber-based intermodal interferometer filter is inserted in the point reflector as a wavelength selector. The synergetic effect including high Raman gain and Rayleigh backscattering intensity in the hybrid of dispersion-shifted fiber and standard single-mode fiber is employed. It presents the capability for flat multi-wavelength random lasing stimulation. As a result, the wavelength channel number of the 6th-order random lasing is 6, with a maximum power variation of 4.66 dB and good temporal stability. The proposed cascaded tunable MWRRFL could provide a versatile source for optical fiber communication, optical fiber sensing, spectrum analysis, etc.

Multi-wavelength Brillouin erbium-doped fiber laser with 40 GHz frequency shift interval assisted by Sagnac loop filter

Multi-wavelength Brillouin erbium-doped fiber laser with 40 GHz frequency shift interval assisted by Sagnac loop filter

L-band of ∼ 1.6 μm tunable multi-wavelength mode-locked Er-doped fiber laser with an MMF- FMF based structure

1.6 μm tunable mode-locked fiber laser are mainly used in the biomedical field, laser processing, and other aspects, have excellent application prospects. We propose a novel MMF-FMF-based device, which acts both as a saturable absorber and a wavelength selection filter. The reduction of insertion loss caused by FMF affects the laser gain competition process, leading to changes in gain allocation and bandwidth allocation. The laser generated stable mode-locked pulses with a repetition frequency of 23.23 MHz at pump powers exceeding 51 mW. By adjusting the angle of the fiber optic squeezer with the PC, successfully achieved switchable single-, dual-, and triple-wavelength lasing outputs, as well as tunable single- and dual-wavelength lasing outputs. The wavelength-tuning ranges for the single- and dual-wavelength lasing outputs were 31 nm (1570 nm-1601 nm) and 24 nm, respectively. The accurately adjustable L-band novel mode-locked fiber laser exhibits enormous potential for application.

OSNR enhancement of Rayleigh-assisted Brillouin-Raman fiber laser via double pass configuration.

We propose and demonstrate a 10 GHz spacing multi-wavelength Brillouin-Raman fiber laser (MBRFL) with wide bandwidth and an outstanding optical signal-to-noise ratio (OSNR). This is achieved by utilizing loop mirror at one end of the laser cavity through a symmetrical bi-directional Raman pumping scheme. The setup is arranged in a double pass configuration by employing different lengths of dispersion compensating fibers (DCF). The attainment of MBRFL with outstanding performance necessitates the optimization of Raman pump power, Brillouin pump wavelength, and DCF length. By employing an 11 km DCF, when setting the Brillouin pump wavelength at 1531.4 nm, 504 Stoke lines are produced with a channel spacing of 0.08 nm. All the counted laser lines have less than a 1-dB peak amplitude variation and are spread across a 40.4 nm bandwidth that covers from 1531.4 to 1571.8 nm wavelength. In this case, the Raman pump power is fixed at 900 mW which results in average OSNR and Stokes peak amplitude level of 28 dB and -7 dBm respectively. To date, this is the simplest cavity design with the widest bandwidth and flattest spectrum together with outstanding OSNR attained in 10 GHz spacing multi-wavelength fiber lasers that incorporate a single low-power Raman pump unit.

Multiwavelength erbium-doped fiber laser using the polarization-hole-burning effect for multichannel acoustic detection.

We propose and demonstrate a novel, to the best of our knowledge, fiber-optic multipoint acoustic detection system based on a multiwavelength erbium-doped fiber (EDF) laser (MWEDFL) using the polarization-hole-burning effect with Fabry-Perot interferometers as the acoustic cavity-loss modulator. A polarization-wavelength-related filter is designed to assign a distinct polarization state to each laser wavelength. By adjusting the polarization state, the polarization-dependent loss and gain of each laser line are tuned to be equal, effectively suppressing the mode competition of EDF and enabling a stable MWEDFL. Each laser line serves as a separate channel for acoustic detection. Theoretical and experimental analyses are conducted to study the transient-response-amplification effect on the acoustic perturbation of the MWEDFL. The results show that the proposed MWEDFL exhibits an amplification effect on the sound-induced cavity-loss modulation, effectively enhancing the sensitivity by 13 dB compared to that obtained using an external-light-source demodulation method. In addition, the MWEDFL based on the PHB effect avoids cross talk between laser channels and can achieve high sensitivity and simultaneous multichannel acoustic detection.

Brief Review of Recent Developments in Fiber Lasers

This review covers the recent achievements in high-power rare earth (RE)-doped fiber lasers, Raman fiber lasers, and Brillouin fiber lasers. RE-doped fiber lasers have many applications such as laser cutting, laser welding, laser cleaning, and laser precision processing. They operate in several wavelength ranges including 1050–1120 nm (ytterbium-doped fiber lasers), 1530–1590 nm (erbium- and erbium–ytterbium-doped fiber lasers), and 1900–2100 nm (thulium- and holmium-doped fiber lasers). White spaces in the wavelength spectrum, where no RE-doped fiber lasers are available, can be covered by Raman lasers. The heat power generated inside the laser active medium due to the quantum defect degrades the performance of the laser causing, for example, transverse-mode instability and thermal lensing. It can even cause catastrophic fiber damage. Different approaches permitting the mitigation of the heat generation process are considered in this review. Brillouin fiber lasers, especially multiwavelength Brillouin fiber lasers, have several important applications including optical communication, microwave generation, and temperature sensing. Recent progress in Brillouin fiber lasers is considered in this review.

Multiwavelength fiber laser based on enhanced bidirectional SOA utilizing Lyot filter

We demonstrated a multiwavelength fiber laser (MWFL) based on two bidirectional semiconductor optical amplifiers (SOAs) and a Lyot filter. The structure is enhanced by placing two -SOAs in a bidirectional region to improve the lasing performance. This resulted in a higher extinction ratio (ER) of 36.05 dB, as earlier work only achieved a maximum extinction ratio (ER) of 17 dB utilizing an SOA based on bidirectional configuration. The performance of the MWFL in unidirectional and bidirectional configurations, as well as different parameter settings of SOA current and polarization controller (PC) angle is examined. Using a unidirectional configuration decreases the amplification on one side of the SOA, hence reducing the wavelength bandwidth by 2 nm, which is equivalent to six lasing lines. According to the wavelength bandwidth of 13 nm and channel spacing of 0.22 nm, the optimal performance of MWFL employing bidirectional configuration is 56 lasing lines within 3 dB bandwidth. Consequently, we decreased each SOA's operating current, resulting in lower lasing lines. Changing the PC angle modifies the polarization degree and state, hence impacting multiwavelength flatness and wavelength bandwidth performance. When the polarizer is removed, the ER and lasing lines are decreased to 42 dB and 9 nm, respectively. The MWFL has high stability with a peak power fluctuation of 0.25 dB in 120 min.

Sagnac-interferometer-based multiwavelength SOA fiber laser assisted by an intensity-dependent loss mechanism.

We demonstrate a Sagnac-interferometer-based multiwavelength fiber laser with an intensity-dependent loss (IDL) mechanism in the L-band region using a semiconductor optical amplifier (SOA) as the gain medium. The IDL mechanism flattens and stabilizes the multiwavelength spectrum. We also investigate the effect of rotation angles of polarization controllers (PCs) at different polarization devices on multiwavelength performance. At best settings, 31 lasing lines within 3dB uniformity were generated with an extinction ratio (ER) of 17dB. Adjusting the half-wave plate of PC1 and PC2 from 0° to 90° shifted the multiwavelength output by 0.01nm and 0.072nm, respectively. PC2 adjustment also affects the multiwavelength flatness as compared to PC1. Furthermore, the number of lasing lines and the ER were directly influenced by the SOA current.

Tunable and switchable multi-wavelength random fiber laser based on random distributed feedback and improved Lyot filter

Tunable and switchable multi-wavelength random fiber laser based on random distributed feedback and improved Lyot filter

Tunable broadband multi-wavelength Brillouin-Raman random fiber laser based on high-order Raman pump

Tunable broadband multi-wavelength Brillouin-Raman random fiber laser based on high-order Raman pump