Dual-wavelength Mode-locked 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 dual-wavelength mode-locked cylindrical vector beam fiber laser based on unpumped EDF saturable absorber and nonlinear polarization rotation

A switchable single- and dual-wavelength mode-locked pulse laser with cylindrical vector beam (CVB) based on an unpumped EDF saturable absorber and a nonlinear polarization rotation (NPR) hybrid mode-locked mechanism has been proposed and experimentally demonstrated. An unpumped EDF saturable absorber is utilized to generate a mode-locked operation that generates high-order laser pulses. Utilizing a hybrid mode-locked mechanism, the signal-to-noise ratio (SNR) and operating stability of the laser are improved compared to the mode-locked operation with a single unpumped EDF saturable absorber. Through adjusting the polarization controller, single- and dual-wavelength stable mode-locked pulses can be easily realized. The single-wavelength mode-locked pulse operates with central wavelengths of 1550.16 nm and 1549.80 nm, repetition frequencies of 6.33 MHz and 6.35 MHz, corresponding to pulse intervals of 158 ns and 157 ns. Further, the long-period grating (LPFG) is used as a mode converter to achieve pulse output with a purity exceeding 95 % in the TM01 and TE01 modes at different operating wavelengths. The proposed fiber laser with a simple structure has provided a flexible pulsed CVB laser source for laser processing, time division, and mode division multiplexing applications.

Dynamics of different pulse types in a single-/dual-wavelength mode-locked fiber laser

Dynamics of different pulse types in a single-/dual-wavelength mode-locked fiber laser

Precise Gas Temperature Measurement Using a Single Dual-Wavelength Mode-Locked Fiber Laser

Precise Gas Temperature Measurement Using a Single Dual-Wavelength Mode-Locked Fiber Laser

All-normal dispersion widely tunable dual-wavelength mode-locked fiber laser based on NALM.

We experimentally and numerically demonstrate the all-normal dispersion (ANDi) ytterbium (Yb)-doped fiber laser based on nonlinear amplifying loop mirror (NALM) mode-locked, which allows tunable single-wavelength and dual-wavelength outputs. The pulses tuning ranges of the dual-wavelength are from 1032.24 nm to 1053.13 nm and from 1047.94 nm to 1069.05 nm, and the repetition frequency difference varies from 1766Hz to 1834Hz. To our knowledge, this is the widest dual-wavelength tuning range of Yb-doped fiber lasers based on NALM mode-locked. We test for 90 minutes and have high stability in both single-wavelength and dual-wavelength. In addition, the pulsed collision dynamics between two solitons at different wavelengths are numerically studied. Numerical results show that during the pulse collision, the two solitons pass through each other and maintain their properties, which also confirms the particle nature of the isolated wave. Our research contributes to the dynamics of dual-wavelength solitons collision in NALM mode-locked fiber laser and provides what we believe to be is a new idea for tunable Yb-doped dual-comb sources.

Tunable and switchable single-/dual-wavelength Er-doped hybrid mode-locked fiber laser by dual-PMFs Lyot filter

Tunable and switchable single-/dual-wavelength Er-doped hybrid mode-locked fiber laser by dual-PMFs Lyot filter

Wavelength-Tunable and Asynchronous Dual-Wavelength Mode-Locked Er-Doped Fiber Laser

Wavelength-Tunable and Asynchronous Dual-Wavelength Mode-Locked Er-Doped Fiber Laser

All-fiber dual-wavelength mode-locked fiber laser based on microfiber-assisted NL-MMI.

We present what we believe is a novel approach to generate a dual wavelength in a single fiber-ring oscillator, which is based on microfiber-assisted nonlinear multimode interference. In the software simulation, the mode locker could not only strengthen the spatial filtering and spectral filtering but could also improve the signal-to-noise ratio of the mode-locked pulse over the single mode fiber-graded index multimode fiber-single mode fibers (SMSs). In the experiment, the stable and compact dual-wavelength mode-locked output was achieved by using the proposed mode-locked fiber laser, without any complex controlling electronics. This new optimized mode-locking method provides a compact and low-cost solution for dual-comb systems.

Dual-Wavelength Mode-Locked Oscillation with Graphene Nanoplatelet Saturable Absorber in Erbium-Doped Fiber Laser

In this work, we demonstrate a dual-wavelength passively mode-locked erbium-doped fiber laser employing graphene nanoplatelet as saturable absorber. The dual-wavelength laser is generated in ~1530 nm and ~1550 nm wavelength regions by splitting the main signal into two separate laser oscillations via a red/blue wavelength division multiplexer. Both the unidirectional and bidirectional dual-wavelength oscillation scheme are investigated, and it is found that the latter is advantageous in providing narrower pulse widths of 890 fs and 980 fs for the respective wavelength region, on top of boosting the pulse energy to the maximum value of 139 pJ and 155 pJ, respectively. It is believed that the bidirectional dual-wavelength oscillation scheme can minimize the overlapping effect between the neighboring pulses that cause pulse distortion as well as signal attenuation compared with unidirectional dual-wavelength oscillation. This work expands the dynamics of cavity structure design for synchronized dual-wavelength mode-locked fiber laser generation.

Sideband-free tunable and switchable dual-wavelength mode-locked fiber laser based on the Lyot filter and spontaneous radiation peaks.

We demonstrate a compact tunable and switchable dual-wavelength fiber laser based on the Lyot filtering effect and the spontaneous radiation peaks of gain fiber. By introducing a period of polarization-maintain Er-doped fiber (PM-EDF), stable dual-wavelength pulses can operate in both the anomalous dispersion region and the normal dispersion region. The corresponding repetition frequency difference of the dual wavelengths has excellent stability while the relative center wavelength can be adjusted in the range of 5 nm to 13 nm. There is no existence of significant sidebands in the optical spectrum during the whole tuning process. This dual-wavelength laser based on two spontaneous radiation peaks in the shorter wavelength direction has great application potential. Our work provides a new design solution for dual-comb sources (DCSs).

Dual-wavelength harmonic mode-locked dissipative soliton resonance of Yb fiber laser

Dissipative soliton resonance (DSR) mode-locked fiber lasers have stimulated great interest recent years due to their unique pulse-breaking-free advantage for scaling soliton pulse energy. However, the mechanism accounting for pulse breaking to generate multipulses in DSR fiber lasers has not reached a consensus. Here, we show that harmonic mode-locked DSR 1-μm Yb-doped fiber laser in the dual-wavelength regime can be realized with a semiconductor saturable absorber mirror (SESAM). In the fundamental frequency (3.5 MHz) mode-locked state, the pulse width continuously broadens from 2 to 8.9 ns as the output power increases from 1.26 to 5.1 mW (pulse energy being from 0.36 to 1.46 nJ), while the pulse peak power is clamped at 0.17 W, highlighting the typical characteristics of DSR mode-locking operation. Through simply adjusting the SESAM’s feedback conditions, the DSR fiber laser can transits from the fundamental-frequency mode locking to harmonic mode-locked states. Harmonic states from the 2nd to 9th order have been observed, with pulse repetition rate enhanced from 7 to 31.5 MHz. Under fixed pump power, increasing harmonic orders leads to reduction of the pulse width and pulse energy but does not change the unique quantization feature of the peak power. The status of the SESAM also guarantees the generation of dual wavelengths centered at 1072.5 and 1079.5 nm with spectral widths of 2.7 and 1.9 nm, respectively. This dual-wavelength harmonic mode-locked DSR Yb fiber laser can find applications in various areas.

Dual-wavelength mode-locked fiber laser based on graphene materials

Dual-wavelength mode-locked fiber laser based on graphene materials

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.

Dual-wavelength mode-locked Er-doped fiber laser in a spectral filter free cavity

We present the experimental investigation of a dual-wavelength passively mode-locked Er-doped fiber laser with strict polarization control. The configuration includes a double-pass amplifier with a Faraday mirror and twisted fiber. We observe that including double-twist fiber cancels circular and linear birefringence and allows obtaining dual-wavelength emission varying the losses in the cavity. In contrast, results including single-twist fiber which only emits single-wavelength due to large circular birefringence.

Tunable and dual-wavelength mode-locked Yb-doped fiber laser based on graded-index multimode fiber device

We have implemented wavelength-tunable and dual-wavelength in an ytterbium-doped passively mode-locked fiber laser using a single mode-graded index multimode-single mode fiber (SMF-GIMF-SMF) device as the saturable absorber (SA) without additional components. Such an all-fiber SA device exhibits fantastic properties with a large modulation depth of 22.9%, a small saturation fluence of 8.3 μJ/cm2, and the transmission curve with a capacity of gain-flattening, which are suitable for the tunable mode-locking generation. Benefiting from the intracavity birefringence-induced filtering effect of the laser cavity, tuning and dual-wavelength operations are obtained. For the tuning operation, the central wavelength of the dissipative solitons (DSs) can be tuned from 1028.5 to 1074.4 nm, with the pulse duration of tens of picoseconds. For the dual-wavelength mode-locking operation, the central wavelengths of dual-wavelength can be switched from 1032.3/1054.1 nm to 1049.3/1072.6 nm. Our results indicate that the SMF-GIMF-SMF device provides a novel platform for wavelength-tunable and dual-wavelength mode-locking in Yb-doped fiber lasers.

Switchable single- and dual-wavelength femtosecond mode-locked Er-doped fiber laser based on carboxyl-functionalized graphene oxide saturable absorber

In this Letter, we demonstrated the switchable single- and dual-wavelength femtosecond soliton generation in single-mode Er-doped fiber lasers with the usage of carboxyl-functionalized graphene oxide (GO-COOH) saturable absorbers (SAs) for the first time, to the best of our knowledge. The fiber laser generated a stable single-wavelength conventional soliton at 1560.1 nm with a pulse duration of 548.1 fs. The dual-wavelength solitons centered at 1531.9 nm and 1555.2 nm with a spacing of approximately 23 nm can be obtained by adjusting the pump power of the cavity. Our experimental results indicated the GO-COOH has great potential to be used in ultrafast fiber lasers as broadband SAs.

NCF–GIMF device as SA and filter utilized in tunable single- and dual-wavelength Yb-doped mode-locked fiber laser

In this letter, by incorporating hybrid structure of no-core fiber (NCF)-graded index multimode fiber (GIMF) as the saturable absorber (SA) and spectral filter simultaneously, not only the switchable noise-like pulses (NLPs) but also the tunable single- and dual-wavelength dissipative solitons (DSs) are obtained from a net normal dispersion Yb-doped mode-locked fiber laser. The NCF–GIMF​ device plays a crucial role in the pulse generation and the wavelength tuning. By means of being stretched, the transmission peak of the NCF–GIMF device can be tuned over 60 nm which is responsible for the wavelength tuning of the oscillator. As the SA, the NCF–GIMF device affords variable saturable absorption properties during the stretching process which are suitable for the ultrafast soliton generation. Based on this device, the center wavelengths of the NLPs are demonstrated to be switchable from 1034.6 nm to 1072.2 nm. The single wavelength DSs with the pulse width at the level of tens of picoseconds can be tuned from 1026.3 nm to 1080 nm. Additionally, the dual-wavelength asynchronized DSs with a spectral interval of 21 nm have a wavelength-tunable range of 13 nm. This all-fiber ultrafast Yb-doped laser with tunable and flexible outputs can satisfy diverse application needs.

Fiber-based dynamically tunable Lyot filter for dual-wavelength and tunable single-wavelength mode-locking of fiber lasers.

We propose and demonstrate a novel dynamically tunable fiber-based Lyot filter for the realization of a dual-wavelength mode-locked fiber laser, operating at center wavelengths of 1535 nm and 1564 nm. The same laser cavity can also be operated in a single-wavelength mode-locked regime with a wavelength tuning range of 30 nm, from 1532 nm to 1562 nm. The proposed dynamically tunable Lyot-filter provides a simple setup for laser mode-locking using a single laser cavity design to generate dual-wavelength pulses, with the flexibility to also allow the generation of single-wavelength pulses with a continuously-tunable center wavelength.

“Periodic” soliton explosions in a dual-wavelength mode-locked Yb-doped fiber laser

We report the “periodic” soliton explosions induced by intracavity soliton collisions in a dual-wavelength mode-locked Yb-doped fiber laser. Owing to the different group velocities of the two wavelengths, the mode-locked solitons centered at different wavelengths would periodically collide with each other. By using the dispersive Fourier transformation technique, it was found that each collision would induce soliton explosions, but none of them would be identical. Therefore, this phenomenon was termed as “periodic” soliton explosions. In addition, the dissipative rogue waves were detected in the dual-wavelength mode-locked state. The experimental results would be fruitful to the communities interested in soliton dynamics and dual-comb lasers.

All-Fiber Dual-Wavelength Mode-Locked Laser Using a Bend-Induced-Birefringence Lyot-Filter as Gain-Tilt Equalizer

Multi-wavelength fiber lasers have emerged as a promising light source for the application in wavelength division multiplexing communication, terahertz wave generation and optical sensing due to high efficiency and robustness. Lyot-filter emerges as a potential device for multi-wavelength generation application. However, because of the high birefringence of polarization maintaining fiber in Lyot-filter, it is difficult to generate broadband dual-wavelength or multi-wavelength mode-locked fiber laser by using common Lyot-filter. In this paper, for the first time, we propose an idea of using the low birefringence induced by bending the single-mode fiber to form a Lyot-filter for dual-wavelength mode-locked fiber laser generation. The dual-wavelength output centers at 1532 and 1556 nm and it may simplify the set-up for dual-wavelength mode-locked laser.