Dual-wavelength Erbium-doped Fiber Laser Research Articles

Dual-wavelength erbium-doped fiber laser with tunable wavelength spacing using a twin core fiber-based filter

A dual-wavelength erbium-doped fiber laser with tunable wavelength spacing was proposed and experimentally demonstrated by using a twin core fiber (TCF)–based filter. Benefiting from the polarization dependence of the TCF-based filter, the laser operated in dual-wavelength oscillation with two orthogonal polarization states. By adjusting the polarization controller, the wavelength spacing was tuned from 0.1 nm to 1.2 nm without shifting the centre position of the two wavelengths. By stretching the TCF, the two wavelengths were simultaneously tuned with fixed wavelength spacing. Such a dual-wavelength fiber laser could find applications in optical fiber sensors and microwave photonics generation.

Stable, uniform, approximately linearly polarized dual-wavelength PM-EDF laser with tunable wide wavelength spacing using a compound filter

A stable uniformity approximately linearly polarized dual-wavelength polarization-maintaining erbium-doped fiber (PM-EDF) laser obtained by using a compound filter is proposed and experimentally demonstrated. By adjusting the polarization controllers (PCs), the output laser can not only be switched between single-wavelength and dual-wavelength operation, but is also tunable. Dual-wavelength lasing has the performance characteristics of uniformity, tunable wavelength spacing, tunable wavelength position, and the same approximately linear polarization. Besides, the peak power fluctuation and wavelength shift are monitored to be less than 0.2 dB and 0.02 nm during an hour, respectively. The characteristics of the two compound filters measured in the experiment are in accord with those of a theoretical analysis.

Tunable dual-wavelength fiber laser based on an MMI filter in a cascaded Sagnac loop interferometer

A widely tunable dual-wavelength erbium-doped fiber laser based on a cascaded Sagnac loop interferometer incorporating a multimode interference filter is proposed and experimentally demonstrated in this paper. The mode selection is implemented by using the cascaded Sagnac loop interferometer with two segments of polarization maintaining fibers, and the wavelength tuning was achieved by using the refractive index characteristic of multimode interference effects. The tunable dual-wavelength fiber laser has a wavelength tuning of about 40 nm with a signal-to-noise ratio of more than 50 dB.

A dual-wavelength erbium-doped fiber laser with widely tunable wavelength spacing

A stable dual-wavelength erbium-doped fiber laser (EDFL) with tunable wavelength spacing and equalized output power is proposed and experimentally demonstrated. The fiber laser uses two fiber Fabry-Perot tunable filters (FFPTFs) as the wavelength filter. The main cavity is divided into two sub-cavities with imbalance cavity losses through a 30/70 optical coupler. The tunable wavelength spacing can be achieved by changing the center wavelength of the filters and the equalized dual-wavelength output power can be achieved by properly controlling the variable optical attenuator (VOA) inserted in the lower-loss cavity.

A switchable dual-wavelength erbium-doped fiber laser based on Sagnac loop inserted with two FBGs

A novel switchable dual-wavelength erbium-doped fiber (EDF) laser is demonstrated. The wavelength selection element consists of two fiber Bragg gratings (FBGs), a polarization controller (PC) and a 3 dB coupler forming a Sagnac loop inserted with two FBGs. We study the effect of coupling ratio on filtering performance in this paper. By adjusting PC, we can change the wavelength-dependent loss, and then using nonlinear polarization rotation effect to suppress the mode competition caused by the homogeneous broadening of EDF, we obtain single- and double-wavelength laser outputs. At room temperature, under 200 mW pump power, dual-wavelength laser is achieved, and the center wavelengths are 1545.34 nm and 1548.20 nm, respectively. The peak power values are −13.36 dBm and −14.58 dBm, and side mode suppression ratios (SMSRs) are 41.10 dB and 39.88 dB, respectively. Within two hours, the maximum fluctuation of peak power is less than 0.7 dB, which shows that the demonstrated fiber laser is stable. Moreover, by adjusting PC, singel-wavelength laser output is obtained, the peak power is −6.27 dBm or −5.45 dBm, and SMSR is 40.03 dB or 39.96 dB at 1545.34 nm or 1548.20 nm, respectively.

The use of a dual-wavelength erbium-doped fiber laser for intra-cavity sensing

A novel intra-cavity sensor based on a dual-wavelength Er-doped fiber laser is proposed. The output power characteristics of the laser are investigated experimentally, and the sensitivity of power to relative cavity loss with different pump currents is studied by defining a sensitivity enhancement factor (SEF). A measurement of the relative sensitivity enhancement of 158.5 is obtained. Moreover, we used such a sensor to measure the absorption peak of NH3 with a 2 m long hollow core photonic crystal fiber as a gas cell.

A 100 mW-level single-mode switchable dual-wavelength erbium-doped fiber laser

A switchable dual-wavelength CW erbium-doped fiber laser with two cascaded fiber Bragg gratings has been proposed and demonstrated experimentally at room temperature. The laser uses a linear resonant cavity configuration incorporating a Sagnac loop with a polarization controller (PC) and can switch flexibly to output a single wavelength or dual wavelengths based on the polarization hole burning (PHB) effect. The slope efficiency and maximum output power can reach 23% and 96 mW, respectively. The two lasing peaks of the laser, with a narrow linewidth output and an optical signal-to-noise ratio of more than 50 dB, are located in the C and L bands of the optical communication window, respectively. The laser shows good stability with respect to the wavelength and output power.

Switchable single- and dual-wavelength erbium-doped fiber laser assisted by four-wave mixing with wide and continuous tunability

A widely tunable and stable erbium-doped fiber laser based on four-wave mixing effect in a highly nonlinear fiber is proposed and experimentally demonstrated. By adjusting reflected power from a dual-selective element, the ring laser is switchable between single- and dual-wavelength operations. The tuning range of the single laser is 22.78 nm, from 1,542.07 to 1,564.85 nm, while the wavelength spacing of the dual-wavelength can be continuously tuned from 0.52 to 22.78 nm. The laser is stable with output peak power fluctuation of <1 dB in 30-min interval.

Multi-wavelength generation by self-seeded four-wave mixing

A cost effective method of generating multi-wavelength based on the cascaded four wave mixing effect is experimentally demonstrated. The proposed scheme is free from external tunable laser sources and pump modulators, resulting from the use of a broadened linewidth tunable dual wavelength erbium-doped fiber laser as intracavity pump. In this configuration, the number of four wave mixing cascades becomes larger in tandem with the increment of erbium-doped fiber amplifier output power. When its output power is set at 20.57 dBm, six waves having optical signal to noise ratio larger than 10 dB are generated. The six waves are stable with peak power fluctuations less than 1 dB within 30 minutes period and tunable with wavelength spacing ranging from 1.03 nm to 11.31 nm.

Highly stable graphene-assisted tunable dual-wavelength erbium-doped fiber laser

A highly stable tunable dual-wavelength fiber laser (TDWFL) using graphene as a means to generate a highly stable output is proposed and generated. The TDWFL comprises a 1 m long, highly doped erbium-doped fiber (EDF) acting as the linear gain medium, with a 24-channel arrayed waveguide grating acting as a wavelength slicer as well as a tuning mechanism to generate different wavelength pairs. The tuned wavelength pairs can range from 0.8 to 18.2 nm. A few layers of graphene are incorporated into the laser cavity to induce the four-wave-mixing effect, which stabilizes the dual-wavelength output by suppressing the mode competition that arises as a result of homogenous broadening in the EDF.

Investigation of Dual-Wavelength Erbium-Doped Fiber Laser Intra-Cavity Absorption Sensor

We propose a dual-wavelength intra-cavity absorption sensor based mode competition. The sensitivity of output power to relative cavity loss in different pump current is studied experimentally by defining a sensitivity enhancement factor (SEF). A measurement sensitivity of 158.5 times that of a single-pass absorption sensor is achieved.

Effect of loop diameter on the performance of MKR-based dual-wavelength erbium-doped fiber laser

A dual-wavelength Erbium-doped fiber laser (EDFL) is demonstrated using a 1.5-m long EDF with a microfiber knot resonator (MKR) structure at the output end. The MKR is fabricated by heating and stretching a 3-cm long piece of EDF to form a microfiber, which is then manipulated to create a knot. The performance of the EDFL is investigated for two different MKR loop diameters. At a loop diameter of 4 mm, dual-wavelength laser is obtained at 1532.4 and 1556.0 nm with peak powers of −7.5 and −7.1 dBm and the corresponding optical signal-to-noise ratios of 22 and 32 dB, respectively. As the MKR diameter is reduced to 2 mm, the operating wavelength of laser shifts to a shorter wavelength, especially for the second lasing with a significant drop in output power due to the bending loss, which is more pronounced at smaller loop diameter. The slope efficiency of the EDFL drops from 0.55 to 0.09% as the MKR diameter decreases from 4 to 2 mm. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:236–238, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27292

A Simple Mechanism to Suppress the Mode Competition for Stable and Tunable Dual-Wavelength Erbium-Doped Fiber Lasers

A suppressant effect for mode competition of dual-wavelength lasing oscillations induced by polarization hole burning effect in an ordinary erbium-doped fiber is proposed and experimentally demonstrated. The polarization hole burning effect is introduced by an all fiber polarization controller directly fused with a segment of erbium-doped fiber. The mechanism of the all fiber polarization controller to suppress the wavelength competition is described in detail. Results show that the mechanism is helpful to obtain stable dual-wavelength lasing oscillations at room temperature in the erbium-doped fiber laser. By adjusting the comb filter, the wavelength tuning between different dual-wavelength oscillations is realized. The side mode suppression ratio of each lasing wavelength is measured to be more than 55dB. The 3dB bandwidth of each lasing oscillation is 0.01nm and the 30dB bandwidth is 0.10nm. The power fluctuation and wavelength shift are measured to be less than 0.8dB and 0.05nm over 32 minutes for all the dual-wavelength lasing oscillations obtained in the experiment.

Switchable linear cavity dual-wavelength fiber laser with equalized output by optimizing intracavity loss

A linear cavity dual-wavelength erbium-doped fiber laser (EDFL) with equalized output power is proposed and experimentally demonstrated. The fiber laser uses an arrayed waveguide grating (AWG) together with two fiber optic switches (OS) to determine the dual-wavelength lasing. The wavelength spacing is switched from 0.8nm to 12.06nm. A 30/70 optical coupler is used to form two different losses cavities in the fiber laser initially. Equalized dual-wavelength output powers are achieved by properly controlling the variable optical attenuator (VOA) inserted in the lower loss cavity. The fiber laser shows good stability with maximum power fluctuations of 1.53dB for all the 16 channels and the side mode suppression ratios (SMSRs) higher than 69.5dB.

Stable dual-wavelength single-longitudinal-mode ring erbium-doped fiber laser for optical generation of microwave frequency

We demonstrate a simple dual-wavelength ring erbium-doped fiber laser operating in single-longitudinal-mode (SLM) at room temperature. A pair of reflection type short-period fiber Bragg gratings (FBGs), which have two different center wavelengths of 1545.072 and 1545.284 nm, are used as the wavelength-selective component of the laser. A segment of unpumped polarization maintaining erbium-doped fiber (PM-EDF) is acted as a narrow multiband filter. By turning the polarization controller (PC) to enhance the polarization hole burning (PHB), the single-wavelength and dual-wavelength laser oscillations are observed at 1545.072 and 1545.284 nm. The output power variation is less than 0.6 dB for both wavelengths over a five-minute period and the optical signal to noise ratio (OSNR) is greater than 50 dB. By beating the dual-wavelengths at a photodetector (PD), a microwave signal at 26.44 GHz is demonstrated.

Stable and Widely Tunable Single-Longitudinal-Mode Dual-Wavelength Erbium-Doped Fiber Laser for Optical Beat Frequency Generation

A stably and widely tunable single-longitudinal-mode dual-wavelength erbium-doped fiber (EDF) laser is investigated for the generation of a tunable optical beat frequency. The lasing wavelength spacing is widely controlled in a range from 3.46 to 13.2 nm, which means that the tunable optical beat frequency in a range from 0.43 to 1.66 THz can be achieved. Nonlinear polarization rotation effect is implemented to stabilize and equalize outputs of the tunable dual-wavelength EDF laser. Since the dual-wavelength fiber laser has a single-longitudinal mode, the proposed dual-wavelength fiber laser is stable.

Switchable dual-wavelength erbium-doped fiber laser based on polarization-maintaining fiber Sagnac loop mirror and fiber Bragg gratings

A switchable dual-wavelength erbium-doped fiber laser is proposed and experimentally demonstrated, which is constructed by a polarization-maintaining fiber Sagnac loop mirror (PMF-SLM) and two FBGs with different wavelengths. Wavelength switching operation is achieved by properly adjusting the polarization controller (PC) in the PMF-SLM. Stable single- or dual-wavelength lasing output can be realized. The maximum amplitude variation for every lasing wavelength is less than 1 dB, and the signal-to-amplified spontaneous emission (ASE) ratio is about 35 dB.

Tunable Dual-Wavelength Erbium-Doped Fiber Laser Using Single Fiber Bragg Grating with Two Coil Heaters

A tunable wavelength-selective fiber Bragg grating (FBG) filter was demonstrated in an erbium-doped fiber ring laser (EDFRL) configuration to achieve a stable and tunable dual-wavelength laser source. The tuning method was based on a thermo-optic effect of a single FBG divided into two segments by two identical coils. Using this coil heater, we showed a continuous wavelength spacing of dual-wavelength output from 0.25 to 5.5 nm. Furthermore, each wavelength could be independently changed during lasing operation without thermal crosstalk between adjacent channels.

Tunable Dual-Wavelength Erbium-Doped Fiber Laser Using Single Fiber Bragg Grating with Two Coil Heaters

Tunable Dual-Wavelength Erbium-Doped Fiber Laser Using Single Fiber Bragg Grating with Two Coil Heaters

Tunable single- and dual-wavelength erbium-doped fiber laser based on Sagnac filter with a high-birefringence photonic crystal fiber

In this paper, we observed and experimentally investigated a high-performance single- and dual-wavelength erbium-doped fiber ring laser based on a Sagnac filter which contains a section of high-birefringence photonic crystal fiber (HB-PCF) and a polarization controller. Incorporation of the high-birefringence photonic crystal fiber can suppress multimode oscillation, improve power stability and increase the optical signal-to-noise ratio (SNR). Wavelength tunable was achieved by using a polarization controller in the Sagnac filter. Highly stable single-, dual-wavelength oscillations are tunable within a wavelength range from 1550 to 1562 nm and SNR as high as 57 dB with narrow line width about 0.011 nm, is experimentally demonstrated.