Multi-wavelength Laser Research Articles

A Tunable and Switchable Multi-Wavelength Erbium-Doped Fiber Ring Laser Enabled by Adjusting the Spectral Fringe Visibility of a Mach-Zehnder Fiber Interferometer

This paper presents a tunable, switchable multi-wavelength emission from an erbium-doped fiber ring laser, enabled by adjusting the spectral fringe visibility of a fiber interferometer filter. The filter is formed with specially designed concatenated tapered fibers to configure a Mach-Zehnder fiber interferometer (MZFI). The laser emission is highly flexible and reconfigurable, allowing for tuning between single- and dual-wavelength operation. The laser can switch sequentially from one up to six wavelengths by fixing the curvature and adjusting the polarization state. The lasing emission is generated over a stable wavelength range between 1559.59 nm and 1563.54 nm, exhibiting an optical signal-to-noise ratio (OSNR) exceeding ~35 dB. The performance of amplitude and wavelength fluctuations were evaluated, indicating an appropriate stability of ~3 dB and a shift less than 0.1 nm within a 45 min period at room temperature. A detailed comparison with the literature is given.

Multi-Wavelength Narrow-Spacing Laser Frequency Stabilization Technology Based on Fabry-Perot Etalon

Classical frequency-stabilized lasers have achieved high-frequency stability and reproducibility; however, their extensive wavelength spacing limits their utility in various scenarios. This study introduces a novel frequency-stabilized laser scheme that integrates a Fabry-Perot etalon (FPE) with digital control technology and wavelength modulation techniques. The FPE, characterized by multiple transmission peaks at minimal frequency intervals, provides stable frequency references for different lasers, thereby enhancing the system’s flexibility and adaptability. An error signal is derived from the first-order differentiation of the FPE’s transmission curve. A 180° phase difference was observed in the feedback output signal when the laser’s central frequency diverged from the reference, determining that the direction of the frequency control was accordingly determined.Employing feedback control, the laser’s output frequency is stabilized at the transmission peak frequency of the FPE. Experimental results demonstrate that this stabilization scheme effectively locks the laser’s output wavelength to different transmission peak frequencies of the FPE, achieving 25 GHz wavelength spacing. The frequency stability is improved by two orders of magnitude on a second-level timescale, maintained within hundreds of kHz, equating to a frequency stability level of 10−10.

Compact multi-port multi-wavelength laser source with Tbps transmission for optical I/O technology

In this paper, we propose and experimentally demonstrate a novel compact multi-port multi-wavelength laser source (MP-MWL) for the optical I/O technology. The multi-wavelength DFB laser array is used for realizing the simultaneous emission of multiple wavelengths. The reconstruction equivalent chirp technique is used to design and fabricate the π-phase shifted DFB laser array to achieve precise wavelength spacing. The number of wavelengths is enlarged through the monolithically integrated wavelength routing architecture (WRA), and 64 optical carriers are obtained with 8 wavelengths in 8 output ports. The proposed MP-MWL has high mode stability and high uniform wavelength spacing. The side mode suppression ratio (SMSR) of each wavelength is more than 40 dB and the wavelength spacing is 100 GHz under 25 °C working environment. A semiconductor optical amplifier (SOA) is monolithically integrated into each output port to amplify the output power. The output power of each port exceeds 15 mW when the current injected into the SOA is 150 mA. Besides, the relative intensity noise (RIN) of all wavelengths is below −130 dB/Hz, and clear 25 Gb/s NRZ eye grams are obtained for the 64 optical carriers with the external lithium-niobate Mach-Zehnder modulator, with a total transmission rate of 1.6 Tbps. The superior performance of the proposed MP-MWL enables it to be a promising approach for the Tbps optical I/O links and high-density chip interconnection system.

Spectral channels increase of multi-wavelength visible laser enabled by SHG-SFG hybrid processes

Spectral evolution in nonlinear optical processes, such as second harmonic generation (SHG) and sum frequency generation (SFG), plays a crucial role in multi-wavelength generation through nonlinear frequency conversion. In this study, the enhancement of spectral performance in a multi-wavelength visible laser facilitated by SHG-SFG hybrid processes is proposed and demonstrated, for the first time to our knowledge. An output of up to eleven wavelengths can be achieved using a six-wavelength pump. Theoretical analysis suggests that the increase in spectral channel count is attributed to the SHG-SFG hybrid processes. Additionally, each nonlinear process operates independently without competition under small-signal approximation, validated through temperature variations. This research not only elucidates the mechanism of spectral evolution in hybrid nonlinear processes but also presents a viable method for improving the spectral performance of a multi-wavelength visible light source.

Programmable multi-wavelength distributed feedback laser array integrated in a liquid crystal polymer waveguide.

Liquid crystal (LC) distributed feedback (DFB) lasers hold significant potential for integrated photonics applications. However, limitations in wavelength spacing for wavelength switching, device size, and compatibility with other technologies have impeded advancements of the LC DFB laser in integration and responsiveness. Herein, we propose a thin-film multi-wavelength DFB laser array utilizing high-resolution patterned programmable nematic LC polymers, enabling rapid switching with high-resolution wavelength spacing between wavelength division multiplexing channels while maintaining a stable single longitudinal mode (SLM) for each laser. The underlying physical mechanism involves modulating the effective refractive index of the DFB laser by varying the LC molecules' orientation angles between adjacent regions of the LC grating to achieve wavelength modulation. Additionally, a specialized LC waveguide design connects the DFB lasers, facilitating wavelength modulation as well as straight-line and bending propagation of the laser. Furthermore, the laser array demonstrates a relatively low energy threshold, facilitating its applications in high-integration scenarios.

An 8-Channel Narrow Linewidth Multi-Wavelength Laser Hybrid Integrated by Photonic Wire Bonding Structures for DWDM Systems

An 8-channel monolithically integrated narrow linewidth multi-wavelength laser array (NL-MLA) combined with the commercial 8×1 planar lightwave circuit (PLC) coupler by the photonic wire bonding (PWB) technique is demonstrated in this paper. A distributed feedback (DFB) laser with the high-reflection and anti-reflection coatings (HR-AR) and the tapered asymmetric corrugation-pitch-modulated (TACPM) grating structure is proposed. The TACPM grating is achieved by the reconstruction equivalent chirp (REC) technique, which is low-cost and of high wavelength accuracy. According to the numerical simulation results, under the unavoidable impact of the facet phase of the HR end, the TACPM DFB laser suppresses the longitudinal spatial hole burning (LSHB) effect significantly, while having better single-mode performance and control of wavelength compared with the conventional HR-AR DFB laser. An 8-channel HR-AR TACPM DFB NL-MLA is fabricated with the 0.8 nm wavelength spacing design. The hybrid integration between the 8-channel NL-MLA and the PLC chip is achieved using the PWB technique. Both good single-mode performance and accurate wavelength interval of 0.8 nm can be obtained when all channels work simultaneously. The laser linewidth is below 273.8 kHz with good uniformity, and the relative intensity noise is under -159.6 dB/Hz for each channel.

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.

Broadband Circularly Polarized Luminescent Films Based on the Heterogeneous Assembly of Cellulose Nanocrystals.

Broadband circularly polarized films display promising applications for multiwavelength lasers and "smart" windows in buildings. Herein, broadband films are fabricated through the heterogeneous assembly of cellulose nanocrystals (CNCs) and thermoplastic polyurethane (TPU) particles in mixed solvents of water and DMF. During the heterogeneous assembly process, a portion of the small TPU particles coassembled with CNCs to form chiral nematic structures and another portion of the TPU particles fused together to form large aggregates. These large aggregates are located around the helical structures of CNCs and induce a twisting effect on the helical axis of the chiral nematic phase. Helical axis twisting continuously occurs in various directions, leading to broad-band reflections of the films. Additionally, multicolor and white right-handed circularly polarized luminescent (CPL) films have been attained by integrating three organic dyes into the chiral structures of CNCs. A high dissymmetry factor value of -0.47 was achieved for the white CPL film.

Telecom-band multiwavelength vertical emitting quantum well nanowire laser arrays

Highly integrated optoelectronic and photonic systems underpin the development of next-generation advanced optical and quantum communication technologies, which require compact, multiwavelength laser sources at the telecom band. Here, we report on-substrate vertical emitting lasing from ordered InGaAs/InP multi-quantum well core–shell nanowire array epitaxially grown on InP substrate by selective area epitaxy. To reduce optical loss and tailor the cavity mode, a new nanowire facet engineering approach has been developed to achieve controlled quantum well nanowire dimensions with uniform morphology and high crystal quality. Owing to the strong quantum confinement effect of InGaAs quantum wells and the successful formation of a vertical Fabry–Pérot cavity between the top nanowire facet and bottom nanowire/SiO2 mask interface, stimulated emissions of the EH11a/b mode from single vertical nanowires from an on-substrate nanowire array have been demonstrated with a lasing threshold of ~28.2 μJ cm−2 per pulse and a high characteristic temperature of ~128 K. By fine-tuning the In composition of the quantum wells, room temperature, single-mode lasing is achieved in the vertical direction across a broad near-infrared spectral range, spanning from 940 nm to the telecommunication O and C bands. Our research indicates that through a carefully designed facet engineering strategy, highly ordered, uniform nanowire arrays with precise dimension control can be achieved to simultaneously deliver thousands of nanolasers with multiple wavelengths on the same substrate, paving a promising and scalable pathway towards future advanced optoelectronic and photonic systems.

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.

Design of 16-wavelength high-power heterogeneous III-V/Si laser arrays with varying stripe width and grating period

Multi-wavelength laser array is currently one of the most attractive technologies to provide high density links for advanced optical communications and computing. The conventional scheme of varying grating period is almost impossible to achieve 8-wavelength or more. And, the optical output power of heterogeneously integrated quantum dot laser can hardly meet the commercial demand. In this paper, we report a 16-wavelength high-power heterogeneously integrated quantum dot distributed feedback laser array. To the best of our knowledge, this is the first heterogeneously integrated quantum dot laser array that tunes the lasing wavelength by combining the scheme of varying the stripe width and grating period of laser units. The effective refractive index of gratings is calculated by eigenmode expansion method. When the grating period is fixed at 198 nm, and the stripe widths of laser units are 2.00 μm, 2.25 μm, 2.60 μm and 3.15 μm, respectively, the corresponding lasing wavelengths are 1307.94 nm, 1308.49 nm, 1309.06 nm and 1309.63 nm, respectively, and the wavelength spacing of the adjacent laser units is about 100 GHz. By additionally adjusting the grating period between 196 nm and 202 nm with 2 nm spacing of grating period, a 16-wavelength QD DFB laser array is designed with the wavelength range from 1294.73 nm to 1336.09 nm. In addition, asymmetric distributed feedback grating is adopted to improve the optical output power at the front-end of laser arrays. The maximum ratio of the output power at the both end of laser units is 19.6 when the grating duty cycles of the front-end and the back-end of the λ/4 phase-shift is 0.7 and 0.5, respectively, and the grating lengths is 250 μm and 450 μm, respectively. This work will promote the performance improvement of heterogeneously integrated quantum dot lasers and develop the quantum dot lasers towards multi-wavelength.

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.

A Multi-Format, Multi-Wavelength Erbium-Doped Fiber Ring Laser Using a Tunable Delay Line Interferometer

This work demonstrates the use of an erbium-doped fiber amplifier (EDFA), a tunable bandpass filter (TBF), and a tunable delay line interferometer (TDLI) to form a ring laser that produces multi-format, multi-wavelength laser beams. The TDLI serves as the core of the proposed laser generation system. TDLI harnesses the weak Fabry–Pérot (FP) interferences generated by its built-in 50/50 beamsplitter (BS) with unalterable filtering characteristics and the interferences with free spectral range (FSR) adjustable from each of its two outputs with nearly complementary phases to superpose and generate a variable interference standing wave. The interferometric standing wave and weak FP interferences are used to form a spatial-hole burning to promote the excitation of multi-format and multi-wavelength lasers. The proposed system enables dual-wavelength spacing ranging from 0.3 nm to 3.35 nm, with a switchable wavelength position at approximately 1527 nm to 1535 nm, providing flexible tunability.

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.

Multi-Wavelength DFB Laser With High Mode Stability and Uniform Spacing for Optical I/O Technology

Multi-Wavelength DFB Laser With High Mode Stability and Uniform Spacing for Optical I/O Technology

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.

Energy-based devices and hyaluronic acid filler, polymer filler, and threads: Cadaveric study.

The objective of this experiment was to investigate the thermal effects on hyaluronic acid fillers, PCL fillers, and PDO threads when exposed to controlled heat. This study aims to provide insights into how these materials respond to thermal energy, which is crucial for safe and effective cosmetic procedures involving combined modalities. Cadaveric tissue was utilized to simulate clinical conditions. Hyaluronic acid fillers were injected at approximately 1 mm and 5 mm thicknesses, with variations in G' value (high and low). PCL fillers were similarly injected in 1 mm and 5 mm thicknesses. PDO threads were also inserted. All materials were injected at a depth of 2 cm. A thermometer was used to measure heat penetration, and a multi-wavelength laser was applied to the tissue. The temperature was maintained at 60°C for 5 min to assess whether heat penetrated more than 3 cm in thickness. Observations were made regarding the heat distribution and any physical changes in the fillers and threads. In thick layers, heat accumulated above the PCL filler without penetrating deeper layers. In thin layers, heat penetration was observed. For the HA fillers, heat energy was not blocked, regardless of the G' value or thickness. For the threads, no significant heat blockage effect was observed. For all materials, no visual changes were detected in any of the materials due to temperature exposure. The findings suggest that the thickness and composition of fillers significantly influence heat penetration. Thick PCL fillers act as a thermal barrier, whereas thin PCL fillers allow deeper heat penetration. Hyaluronic acid fillers do not impede heat transfer, regardless of their physical properties. PDO threads do not exhibit any notable thermal resistance. These insights are essential for optimizing the safety and efficacy of combined filler and energy-based device treatments in esthetic medicine.

Over 100 mW O-Band Multi-Wavelength DFB Laser Array for Optical I/O Technology

Over 100 mW O-Band Multi-Wavelength DFB Laser Array for Optical I/O Technology

Tuning Multi-wavelength Lasing in Rhodamine 640/Methylene Blue/Ag NW Random Lasers

Tuning Multi-wavelength Lasing in Rhodamine 640/Methylene Blue/Ag NW Random Lasers

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