Dual-wavelength Erbium-doped Fiber Laser Research Articles

Dual-wavelength erbium-doped mode-locked fiber laser based on CoPS3 saturable absorber

An erbium-doped mode-locked fiber laser based on CoPS3 saturable absorber was successfully constructed and ultrashort pulsed light was obtained. The CoPS3 nanosheets solution was prepared using the liquid-phase exfoliation technique, and then drop-coated onto a tapered fiber as a saturable absorber. The fiber laser based on CoPS3 saturable absorber could output conventional solitons at the central wavelengths of 1557.46 nm or 1532.12 nm, respectively, as well as simultaneously output conventional solitons at dual wavelengths of 1531.56 nm and 1557.32 nm, with the ability to switch between the three operational states. The achieved minimum pulse width was 1.59 ps. In addition to conventional solitons, the laser demonstrated the capability to generate bound-state solitons. This study highlights the effectiveness of CoPS3 as a reliable optical modulator for fiber lasers and illustrates its potential for applications in ultrafast optics.

Switchable emissions of an Erbium-doped fiber laser using cascaded MZIs based on CHCF

In this work, a single and dual-wavelength erbium-doped fiber laser (EDFL) based on two Mach-Zehnder interferometers (MZIs) in cascade structure was experimentally validated. MZIs were assembled by joining a capillary hollow-core fiber (CHCF) piece between two multimode fibers (MMFs) sections. The switchable operation is reached by moving the spectrum of one MZI when the temperature is increased. The maximum measured signal noise to ratio (SNR) was more than 50 dB for the single and dual-wavelength laser lines. Besides, stable output is shown since no power and wavelength variations were noticed. It is important to mention that emissions are obtained at precise wavelength positions and not arbitrarily as described by other investigations. This EDFL can be used in applications of optical fiber communications systems and fiber sensing.

A dual-wavelength erbium-doped fiber laser for high resolution strain sensing with compound filter of a Sagnac loop and a long period fiber grating

A dual-wavelength erbium-doped fiber laser (EDFL) strain sensing system composed of compound filter of a long period fiber grating (LPFG) and a Sagnac loop is proposed. Polarization maintaining fiber (PMF) in Sagnac loop acts both an interference filter and a strain sensing probe with high sensitivity, low cost, and low loss. LPFG is used to modulate the transmission wavelength and bandwidth of EDFL through adjusting its bending curvature. Flexible laser output with single wavelength and dual-wavelength tunable wavelength band of 10 nm is achieved in EDFL. The measurement sensitivity of strain reaches 8.33 pm/με, while the 3 dB linewidth is less than 2 nm and the signal-to-noise ratio (SNR) exceed 36 dB. This sensor has a high resolution (R) of 0.11 nm and a high quality factor (Q) of 38.13. The experimental results suggest that the system is suitable for precise strain measurement and has significant potential in fields like biomedicine, environmental monitoring, health monitoring, and aerospace.

Optimization of Dual-Wavelength linear cavity Erbium-Doped fiber laser based on pairs of fiber Bragg gratings

There are few reports in the field of linear cavity dual-wavelength fiber lasers about the laser output characteristics when 3-dB fiber loop mirror (FLM) and Fiber Bragg grating (FBG) are used as full reflective mirrors, respectively. Additionally, there is scarce research on further tuning of the FBG parameters (reflectivity and center wavelength interval) to study dual-wavelength fiber lasers. In this paper, we compare the performances of dual-wavelength lasing outputs between the 3-dB FLM-FBG cavity and the FBG-only cavity in a linear-cavity erbium-doped fiber laser (EDFL) based on the polarization hole burning effect. The results show that the optical signal-to-noise ratios (OSNRs) of the dual-wavelength lasing outputs with the FBG-only cavity are approximately 4 ∼ 5 dB higher than those with the 3-dB FLM-FBG cavity. Furthermore, the lasing output performances based on the FBG-only cavity are compared when the reflectivities of the output-mirror FBGs are the same or different. It is observed that the dual-wavelength laser with the same output reflectivity leads to higher OSNR, slope efficiency, and stability. Moreover, by varying the center wavelength interval of pairs of FBGs in the FBG-only cavity to values of 4 nm, 8 nm, and 12 nm respectively. It is shown that wider intervals result in higher OSNRs but lower laser slope efficiency. Finally, we demonstrate a dual- wavelength linear cavity EDFL operating at room temperature with two lasing wavelengths of 1550 nm and 1562 nm. The laser results in OSNRs around 50.62 dB and 50.93 dB; center wavelength variations of less than 0.030 nm and 0.035 nm; output power fluctuations of less than 0.061 mW and 0.059 mW, respectively.

A high resolution and large measurement range strain sensor based on Sagnac loop and fiber Bragg grating in dual-wavelength erbium-doped fiber laser

A high resolution and large measurement range strain sensor based on Sagnac loop and fiber Bragg grating in dual-wavelength erbium-doped fiber laser

Interval Adjustable Dual-Wavelength Erbium-Doped Fiber Laser Based on Cascaded Two Mach-Zehnder Interferometers

An interference filter is designed by cascading two Mach-Zehnder interferometers (MZIs), which is then utilized in the construction of a wavelength interval adjustable dual-wavelength Erbium-doped fiber laser (EDFL). Each MZI consists of two 3 dB optical couplers (OCs) connected in series. The input light is split into two arms at the first OC and recombined at the second OC. The first MZI (MZI 1) has a smaller free spectral range (FSR) and is used for selecting the output wavelength of the laser. The second MZI (MZI 2) has a larger FSR and forms an envelope structure on the comb-like spectrum of MZI 1. By adjusting the optical path difference between the two arms of MZI 2, the FSR of the envelope can be changed, thereby altering the interval of the output wavelengths. The implemented filter is inserted into the EDFL to achieve stable dual-wavelength output. By stretching one arm of MZI 2, the interval of the dual-wavelength can be adjusted from 4.64 to 13.94 nm, with the side-mode suppression ratio of over 44 dB for all wavelengths.

A dual wavelength erbium-doped random fiber laser with tunable wavelength separation

A dual wavelength erbium-doped random fiber laser, based on a micro air cavity, is experimentally demonstrated. The proposed random fiber laser has a lower threshold of about 15 mW and a high optical signal to noise ratio of over 40 dB. Changing the length of air cavity realizes a stable dual wavelength output with a variable and controllable separation from 2.5 nm to 20.2 nm. The measured fluctuation of lasing wavelengths and the output powers are smaller than 0.005 % and 2.25 %, respectively, which are proved to be very highly stable with such a relatively simple structure. It is expected to meet the growing demand of applications including optical communication, lidars, fiber sensing, and so on.

Fast dual-comb spectroscopy based on a dual-wavelength all-fiber ring laser with high repetition rate

We demonstrate fast dual-comb spectroscopy based on a high-repetition-rate dual-wavelength erbium-doped fiber laser with a large repetition rate difference. It can operate in three different dual-wavelength states with repetition rate differences of 4.32, 2.74 and 3.635 kHz, respectively. To the best of our knowledge, the corresponding refresh time can be as low as 231 μs, which is the fastest in dual-comb spectroscopy using a single fundamentally mode-locked all-fiber laser. The high repetition rate of approximately 154.68 MHz provides a maximum optical frequency bandwidth of 4.37 THz. Dual-comb spectroscopy was used to measure the transmittance curve of the Fabry–Perot etalon.

Dual-wavelength Q-switched erbium-doped fiber laser using an SMF-MMF-SMF structure and graphene oxide

Dual-wavelength Q-switched erbium-doped fiber laser using an SMF-MMF-SMF structure and graphene oxide

Highly Stable Switchable Emissions of an Erbium-Doped Fiber Ring Laser Using Cascaded MZIs Based on CHCF

A stable, single, and dual-wavelength erbium-doped fiber laser (EDFL), based on two Mach–Zehnder interferometers (MZIs), arranged in a cascade configuration, was proposed for experimental purposes. Both MZIs were assembled by splicing a capillary hollow-core fiber (CHCF) section between two multimode fibers (MMFs) segments. The novelty of this single and dual-wavelength EDFL is that the switchable operation of the laser is achieved by thermally tuning the interference pattern of one MZI and not by adjusting the polarization state inside the fiber ring cavity. The maximum measured value of SNR was 58.9 dB for the single and dual-wavelength laser emissions. Moreover, the stable output power exhibited by this EDFL, in terms of minimal power and wavelength fluctuations, at 0.05 dB and 10 pm, was detected during the single and dual-wavelength operation. It is worth noticing that switching is achieved at exact wavelength locations with a separation of 1.8 nm and not randomly, as reported by other works. These features make this switchable EDFL an appealing candidate for application in optical fiber communication systems and fiber sensing.

Tunable and Switchable Dual-Wavelength SLM Narrow-Linewidth Fiber Laser with a PMFBG-FP Filter Cascaded by Multi-Ring Cavity

A single longitudinal mode (SLM) dual-wavelength switchable erbium-doped fiber laser (DW-EDFL) based on polarization-maintaining fiber Bragg grating Fabry–Perot cavity (PMFBG-FP) cascaded multiple sub-ring cavities (MSCs) is proposed. A PMFBG-FP with a narrow-band transmission peak and MSCs was implemented as an optical filter to achieve stable dual-wavelength laser output and guaranteed SLM status. By stretching the PMFBG, a highly stable dual-wavelength tunable output could be achieved with a maximum tuning interval of 0.17 nm. The optical signal-to-noise-ratio (OSNR) at dual-wavelength lasing was higher than 57 dB, and the optimal wavelength and power fluctuations within 0.5 h were 0.01 nm and 0.79 dB, respectively. Meanwhile, the measured linewidths of each wavelength were 1.55 kHz and 1.65 kHz, respectively. The measured polarization states of the two laser wavelengths were linear and orthogonal, with a degree of polarization (DOP) of nearly 100%.

A Dual-Wavelength Fiber Laser Sensor with Temperature and Strain Discrimination.

This work presents a dual-wavelength C-band erbium-doped fiber laser assisted by an artificial backscatter reflector. This fiber-based reflector, inscribed by femtosecond laser direct writing, was fabricated into a single mode fiber with a length of 32 mm. The dual-wavelength laser obtained, centered at 1527.7 nm and 1530.81 nm, showed an optical signal-to-noise ratio over 46 dB when pumped at 150 mW. Another feature of this laser was that the power difference between the two channels was just 0.02 dB, regardless of the pump power, resulting in a dual emission laser with high equalization. On the other hand, an output power level and a central wavelength instability as low as 0.3 dB and 0.01 nm were measured, in this order for both channels. Moreover, the threshold pump power was 40 mW. Finally, the performance of this dual-wavelength fiber laser enhanced with a random reflector for sensing applications was studied, achieving the simultaneous measurement of strain and temperature with sensitivities around 1 pm/με and 9.29 pm/°C, respectively.

Dual-wavelength mode-locked laser based on optimization of erbium-doped fiber length

The length of an erbium-doped fiber laser is optimized to develop a dual-wavelength nonlinear polarization rotation mode-locked erbium-doped fiber laser. The mode-locked laser can emit two stable wavelengths of 1530 nm and 1558 nm with a fiber length of 570 cm. With the absorbed pump power of 150 mW, the maximum average output power of 19.2 mW with the repetition frequency of 11.95 MHz and pulse width of 389 fs is obtained.

Switchable dual-wavelength erbium-doped fiber laser based on the broadband filtering performance of tapered long period fiber gratings

In this paper, a switchable, dual-wavelength erbium-doped fiber laser, based on the broadband filtering performance of a tapered long-period fiber grating, is experimentally demonstrated. The lasing emission can be built up in sets of dual-wavelengths in the entire C-band, with variable and controllable separation between laser lines from 6.75 nm to 35 nm when the optical fiber filter structure is gradually bent.

Stable dual-wavelength laser incorporating polarization-maintaining erbium-doped fiber

A stable dual-wavelength erbium-doped fiber laser is proposed and experimentally demonstrated. The mode competition in the gain medium was suppressed by enhancing the polarization hole burning mechanism through incorporation of polarization maintaining erbium-doped fiber and nonlinear polarization rotation. The fiber laser displayed high stability with lasing side-mode suppression ratios of 60.69 and 60.57 dB. Additionally, the negligible peak power fluctuation of 0.01 dB was achieved at 1557.17 and 1560.19 nm with both peak powers of 0.23 mW and 3-dB bandwidth of 0.028 and 0.025 nm, respectively. These findings provide insights for an enhanced seed laser source design for remote dual-wavelength fiber laser applications.

Fiber curvature sensor based on dual-wavelength erbium-doped fiber laser (DWEDFL) with gain competitive intensity difference demodulation

A fiber laser curvature sensor based on dual-wavelength gain competitive intensity difference demodulation is proposed and experimentally demonstrated. Here a linear cavity dual-wavelength erbium-doped fiber laser (DWEDFL) is build with two filter components i.e. fiber Bragg gratings (FBG) with very close center wavelengths. Since the dual wavelengths are sharing the same gain medium erbium-doped fiber (EDF), gain competition mechanism is formed with sensitive feature to external measurand curvature. Besides, the curvature information is demodulated by subtracting the power of the dual wavelengths. Experimental results show a total sensitivity as high as -57.22 dB/m−1. Our scheme not only improves the measuring sensitivity, but also eliminates the effects of source power jitter and external disturbances for example temperature shift since they do almost the same impact on the dual wavelengths.

High Performance Tunable Dual-Wavelength Erbium-Doped Fiber Laser Implemented by Using Tapered Triple-Core Photonic Crystal Fiber

Based on tapered Triple-Core Photonic Crystal Fiber (TCPCF), a high performance tunable Dual-Wavelength Erbium-Doped Fiber Laser (DW-EDFL) is proposed and experimentally demonstrated. The mode-coupling among three cores of TCPCF appears periodically and becomes further enhanced in tapered TCPCF, which are beneficial to form a filter to select lasing wavelength. A series of tapered TCPCFs with different taper lengths are fabricated and inserted into tunable DW-EDFL as filters. Multiple groups of tunable dual-wavelength lasing outputs are achieved by using the tapered TCPCF filter with a waist diameter of 126 μm. The maximum tunable range can reach up to 14.36 nm and the side mode suppression ratio of all lasing outputs are above 52 dB. In addition, the tunable single- and triple-wavelength lasers are also obtained. The tunable single-wavelength laser has an excellent linear response to strain and can be applied to realize a high-sensitivity strain sensor with the highest strain sensitivity of -13.1 pm/μe.

Dual-wavelength self-starting mode-locking Er-doped fiber laser with MnPS<sub>3</sub> saturable absorber

As a member of the metal phosphorus trichalcogenide family, MPS<sub>3</sub> is widely used in nonlinear optics and devices, which can be regarded as a significant benefit for the excellent photonic and optoelectronic properties. In this work, the MnPS<sub>3</sub> nanosheet is prepared by the chemical vapor transport method and the MnPS<sub>3</sub> saturable absorber is demonstrated by modifying mechanical exfoliation. To the best of our knowledge, the dual-wavelength self-starting mode-locking erbium-doped fiber laser with MnPS<sub>3</sub> saturable absorber is demonstrated for the first time. The dual wavelength mode-locked laser with a pulse repetition rate of 5.102 MHz at 1565.19 nm and 1565.63 nm is proposed. Its maximum output power at the dual-wavelength is 27.2 MW. The mode-locked laser can self-start and stably run for more than 280 h.

Q-Switched dual-wavelength erbium-doped fiber laser using graphene as a saturable absorber

We proposed stable Q-switched dual-wavelength initiated by graphene as saturable absorber inside erbium-doped fiber laser cavity. Continuous-wave and pulse spectrum of erbium-doped fiber laser (EDFL) was successfully demonstrated and analysed where the lasing starts at a pump power of 50.4 mW. Threshold pump power generates continuous-wave at 1560 nm which is then shifted to 1558.7 nm as the SA is inserted. Q-switched EDFL generates a maximum repetition rate of 115.9 kHz which corresponds to a pulse width of 41 μs. The generation of dual-wavelength at two different wavelengths are also demonstrated in these works.

Dual-wavelength mode-locked erbium-doped fiber laser based on tin disulfide thin film as saturable absorber

The use of tin disulfide (SnS2) as a candidate material for saturable absorption in nonlinear optical devices is investigated in this article. A dual-wavelength soliton mode-locked fiber laser is demonstrated using a fabricated SnS2 thin film as a saturable absorber within an erbium-doped fiber laser cavity. The laser generates two peaks centered at 1536.7 and 1562.6 nm, with a pulse width of 5.3 ps. The experimental results indicate that the SnS2 thin film has the required absorption characteristics to realize good mode-locked operation. Thus, we confirm that SnS2 has great potential to be used in multiwavelength ultrafast fiber laser applications.