Brillouin-erbium Fiber Laser Research Articles

Tunable Multiwavelength Brillouin-Erbium Fiber Laser Based on Fiber Amplified Loop

A novel linear multiwavelength Brillouin-erbium fiber laser based on a nonlinear fiber amplified loop is demonstrated. The nonlinear fiber amplified loop induces wavelength-dependent cavity loss and it provides flexibility on controlling the amount of light reflected and transmitted into and out of the laser's cavity. At the Brillouin pump (BP) power of 25 mW and the 980 nm pump power of 200 mW, 21 output channels with 0.08 nm channel spacing are achieved. We realize the tunable output of multiwavelength through adjusting the polarization controller and the BP wavelength. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1741–1743, 2013

Widely tunable L-band multiwavelength brillouin-erbium fiber laser incorporating a bismuth-based erbium-doped fiber

We have demonstrated a widely wavelength tunable Brillouin-erbium fiber laser (BEFL) with multiwavelength lasing in the L-band region. The Brillouin pump (BP) is injected from the external cavity and preamplified by an intracavity bismuth-based erbium-doped fiber amplifier (Bi-EDFA) before entering the single-mode fiber. By combining the broadband gain of Bi-EDFA and BP preamplification technique within the linear cavity, our BEFL exhibits a broad tuning range of 65 nm from 1555 to 1620 nm, which is the widest one achieved in L-band BEFLs to the best of our knowledge. The maximum number of wavelengths obtained within this wavelength range is 12 channels with a spacing of approximately 0.088 nm. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1574–1577, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27664

A widely tunable double-Brillouin-frequency spaced multiwavelength fiber laser with a 110 nm tuning range

A wideband double-Brillouin-frequency spaced multiwavelength Brillouin–erbium fiber laser (MWBEFL) with 110 nm tuning range is demonstrated. The fiber laser utilizes simple compound-ring cavity structures which confine the odd-order Brillouin–Stokes (BS) signals within the right ring and couple out the initial Brillouin pump signal (BP) and even-order BS signals to generate a 0.176 nm spacing multiwavelength. A wavelength- and bandwidth-tunable optical band-pass filter (TBF) is used to manipulate the location of self-lasing cavity and to get a wideband tuning range. All the generated output channels exhibit good stability.

Simple multiwavelength Brillouin–Erbium-doped fiber laser structure based on short SSMF

An efficient multiwavelength Brillouin–Erbium fiber laser (BEFL) was developed by improving the feedback mechanism of Brillouin Stokes lines. The BEFL performance in terms of threshold power and wavelengths count was improved by using a new structure of double pass amplification cavity. The new structure utilized the variable optical coupler (VOA) not only as the input and output ports but also to form a fiber loop mirror that reduces the number of optical components, thus, only three optical components were needed. By optimizing the Brillouin and 1480nm pump power, up to 41 channels and 26 channels were obtained using 0.6km and 0.3km long of standard single mode fiber (SSMF), respectively.

Flattening effect of four wave mixing on multiwavelength Brillouin-erbium fiber laser

A multiwavelength Brillouin-erbium fiber laser with enhanced output uniformity is demonstrated and its performance with and without the assistance of four wave mixing (FWM) is compared. The presence of FWM effect is proven by the generation of anti-Stokes wave and higher-order Stokes wave. This scheme is successful in flattening the multiwavelength output. At Brillouin pump wavelength of 1,550 nm, between the first and the last output channel, peak power differences of 4.59 and 8.32 dB are recorded for the scheme with and without the assistance of FWM, respectively. This represents 3.73 dB improvement in the multiwavelength output power uniformity.

A Q-switched multi-wavelength Brillouin erbium fiber laser with a single-walled carbon nanotube saturable absorber

A Q-switched multi-wavelength Brillouin erbium fiber laser (MWBEFL) is demonstrated using a single-walled carbon nanotube–polyethylene oxide (SWCNT–PEO) saturable absorber (SA). The SA is fabricated by cutting off a small part of the developed SWCNT–PEO film and sandwiching it in between two FC/PC (fiber connector/physical contact) fiber connectors. Multi-wavelength combs with ten lasing lines and spacing of 0.158 nm are obtained by the use of 2 km long dispersion compensating fiber as the Brillouin gain medium and a four-port circulator to isolate and circulate the odd-order Stokes signals. Q-switched pulse trains with a repetition rate of 105.2 kHz and a pulse width of 0.996 μs are obtained in the proposed MWBEFL at a 1480 nm pump power of 120 mW and a Brillouin pump power of 5.4 dBm.

Double-Brillouin-Frequency Spaced Multiwavelength Generation in a Ring Brillouin-Erbium Fiber Laser

We demonstrate the double-Brillouin-frequency spaced multiwavelength generation at room temperature by using a simple ring Brillouin-erbium fiber laser. The Brillouin pump is pre-amplified before entering the single-mode fiber, the odd Stokes and even Stokes are amplified in two opposite directions. All amplification provided by a home-made bi-directional operation erbium-doped fiber may achieve high intensity of Brillouin Stokes that leads to the homogenous gain saturation. Twelve even Stokes and thirteen odd Stokes with a wavelength spacing of 0.172 nm (20 GHz) are simultaneously obtained for 6 dBm Brillouin pump power and 120 mW pump power at 980 nm. The influence of different Brillouin and erbium-doped-fiber pump powers on multiwavelength and tuning range are investigated in detail.

A tunable self-seeded Brillouin/erbium fiber laser utilizing an asymmetrical twin core fiber based Mach–Zehnder interferometer

A tunable self-seeded Brillouin/erbium fiber laser (BEFL) utilizing an asymmetrical twin core fiber based Mach–Zehnder interferometer (ATCF-MZI) is proposed and demonstrated. The proposed self-seeded BEFL has the advantage of being able to generate up to 17 output channels with high optical signal to noise ratio (>10 dB). The Brillouin pump is self-seeded in the laser cavity instead of the extra Brillouin pumping. By bending the ATCF-MZI, an 8 nm wavelength-tunable range is achieved. This self-seeded BEFL shows linear tunability and good stability. Meanwhile, the experimental results indicate that the laser output with operation wavelength away from the free-running cavity mode has better output characteristics.

Tunable Brillouin-Erbium Comb Fiber Laser in a Linear Cavity With a Single-Mode Tellurite Fiber

We demonstrate a Brillouin-erbium fiber laser in a linear cavity with a single-mode tellurite fiber. Only 132-m tellurite fiber is used in the cavity because of the high Brillouin gain coefficient. Both the backward and forward Brillouin lines are reflected into the cavity, which experience dual-pass Brillouin gain. With a tunable filter, the gain is equalized in the erbium-doped fiber bandwidth. About 40 comb lines spaced by 7.91 GHz are obtained and the line number is kept in the tunable range from 1528 to 1565 nm with 37 nm. The average output power fluctuates from 44 to 48 mW in the tunable range.

Generation of efficient 20 GHz optical combs in a Brillouin-erbium fiber laser

A tunable multiwavelength Brillouin-erbium fiber laser is experimentally demonstrated with a double-Brillouin-frequency spacing. This double-frequency shifter is constructed by incorporating a four-port circulator to isolate and circulate the odd-Stokes signals through the 10 km long non-zero dispersion shifted fiber, which acts as a Brillouin gain medium. The output even-order Stokes signals are amplified in the erbium gain block formed in a ring cavity. Up to 15 lasing lines with a wavelength spacing of 0.173 nm have been achieved at a 980 nm pump power of 50 mW and a Brillouin pump of 3 dB m. The multiwavelength laser source exhibits a 10 nm tuning range from 1552 to 1562 nm with the optical signal-to-noise ratio of the desired output channels at around 34.5 dB.

Double spacing multi-wavelength L-band Brillouin erbium fiber laser with Raman pump

A new multi-wavelength Brillouin erbium fiber laser (BEFL), which operates in the L-band region with double frequency Brillouin spacing, is demonstrated. This design uses a Raman pump (RP) and a piece of 2 km highly nonlinear fiber as a gain medium. The double frequency spacing is achieved by employing a dual ring configuration, which is formed by utilizing a four-port circulator that removes the odd-order Stoke signals. Twenty Stokes and seventeen anti-Stokes lines, which have optical signal to noise ratio (OSNR) greater than 15 dB, are generated simultaneously with a spacing of 0.16 nm when Brillouin pump and RP powers were fixed at the optimum values of 8 dBm and 40 mW, respectively. The BEFL can be tuned in the range between 1591 nm to 1618 nm. The proposed configuration increases the number of lines generated and the OSNR, and thus allows a compact multi-wavelength laser source to be realized.

Characteristics of a Brillouin-erbium fiber laser based on Brillouin pump preamplification

A single-mode Brillouin-erbium fiber laser (BEFL) is realized using only a 5 m single-mode fiber (SMF) as Brillouin gain medium, which to our best knowledge is the shortest SMF ever used to construct a BEFL. The Brillouin pump (BP) preamplification technique is adopted using a bidirectionally amplified erbium-doped fiber amplifier inside the BEFL cavity. This BEFL presents a high optical signal-to-noise ratio (~40 dB), a large output power (~10 mW), and a low 980 nm pump threshold (~15 mW). Experimental results indicate that this threshold increases with the BP power. Two lower and upper BP thresholds exist for the BEFL onset and turnoff, respectively, for a fixed 980 nm pump power. Moreover, the output power of this BEFL increases linearly with the 980 nm pump power at the same slope efficiency of ~10% for various BP powers, but decreases linearly with the BP power at the same slope efficiency of ~-26% for various 980 nm pump powers.

Widely Tunable C $+$ L Bands Multiwavelength BEFL With Double-Brillouin Frequency Shifts

A wideband multiwavelength Brillouin–erbium fiber laser (BEFL) with double Brillouin frequency spacing is demonstrated. The fiber laser structure utilizes a tunable band-pass filter and a pre-amplified Brillouin pump technique within a ring cavity. An average of six Brillouin–Stokes signals in C <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex Notation="TeX">$+$</tex></formula> L bands with a constant wavelength spacing of 0.174 nm can be turned over a span of 80 nm from 1530 nm to 1610 nm. Total average output power of 8.5 mW from this laser structure was achieved. All the generated Brillouin–Stokes signals exhibit good stability, and high peak power of above <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$-$</tex></formula> 10 dBm per signal was demonstrated.

Tunable hybrid Brillouin-erbium comb fiber laser in a composite cavity with a single-mode tellurite fiber

We demonstrate a hybrid Brillouin-erbium fiber laser in a composite cavity with a single-mode tellurite fiber. Only a 200 m long tellurite fiber is used in the cavity due to the high effective nonlinearity. The double pass of the tellurite fiber in the linear part is advantageous for improving the Brillouin gain and increasing the comb lines. With a tunable filter, more than 70 comb lines spaced by 7.888 GHz are obtained at 1565 nm. The line number is kept around 60 in the tunable range of 30 nm from 1535 to 1565 nm. Compared with silica fibers, the tellurite fiber can generate a larger number of Brillouin lines in a wider tunable range.

Double Brillouin frequency spaced multiwavelength Brillouin-erbium fiber laser with 50 nm tuning range

A 50 nm tuning range multiwavelength Brillouin-erbium fiber laser (MWBEFL) with double Brillouin frequency spacing is presented. Two separated gain blocks with symmetrical architecture, consisted by erbium-doped fiber amplifiers (EDFAs) and Brillouin gain media, are used to generate double Brillouin frequency spacing. The wider tuning range is realized by eliminating the self-lasing cavity modes existing in conventional MWBEFLs because of the absence of the physical mirrors at the ends of the linear cavity. The Brillouin pump (BP) is preamplified by the EDFA before entering the single-mode fiber (SMF), which leads to the reduction of threshold power and the generation enhancement of Brillouin Stokes (BS) signals. Four channels with 0.176 nm spacing are achieved at 2 mW BP power and 280 mW 980 nm pump power which can be tuned from 1525 to 1575 nm.

Tunable self-seeded multiwavelength Brillouin–erbium fiber laser using an in-line two-taper Mach–Zehnder interferometer

A tunable self-seeded multiwavelength Brillouin–erbium fiber laser (BEFL) using an in-line two-taper Mach–Zehnder interferometer (MZI) is proposed and demonstrated experimentally. In this scheme, the Brillouin pump is self-excited, then used to seed the Brillouin Stokes lines by cascaded stimulated Brillouin scattering (SBS) in the single mode fiber (SMF). The wavelength of output multiwavelength comb is tuned by bending an in-line two-taper MZI filter made of standard SMF. The generation of up to 35 wavelength comb with uniform power distribution has been obtained. The central wavelength of the multiwavelength comb has 11nm tuning range, and the tuning process is quantifiable.

Millimeter wave carrier generation based on a double-Brillouin-frequency spaced fiber laser

An all-optical generation of a millimeter wave carrier from a multiwavelength Brillouin-erbium fiber laser is presented. Four-channel output with spacing of about 21.5 GHz is generated from the fiber laser by controlling the gain in the cavity. A dual-wavelength signal with spacing correspondent to six orders of Brillouin frequency shift is obtained by suppressing the two channels at the middle. Heterodyning these signals at the high-speed photodetector produces a millimeter wave carrier at 64.17 GHz. Temperature dependence characteristic of Brillouin frequency shift realize the flexibility of generated millimeter wave frequency to be tuned at 6.6 MHz/ °C.

Compact Brillouin bismuth–gallium–aluminum co-doped erbium doped fiber laser

A single-wavelength Brillouin–erbium fiber laser (BEFL) is demonstrated using high germanium dopant concentration fiber and bismuth–gallium–aluminum co-doped high concentration erbium doped fiber (EDF). A 20-m long high Ge-doped fiber is used to provide nonlinear gains to generate a stimulated Brillouin scattering (SBS), and a 4.3-m long Bi–Ga–Al EDF provides linear gains to amplify the SBS. The relationship between the fiber parameters (dopant concentration, effective area, length and so on) of both linear and nonlinear medium and the output performance was discussed. The BEFL power increases as the effective area of the high Ge-doped fiber decreases. There is an optimum length in the high Ge-doped fiber which is 20-m long in this paper. The BEFL output power also increases as the output power of the Bi–Ga–Al EDF increases. The output performance increases as the erbium doping concentration increases. It is necessary to get the effective area of the Bi–Ga–Al EDF large enough to decrease the fiber loss. The optimum length in the Bi–Ga–Al EDF is 4.3m. The BEFL operates at 1563.61nm, which is upshifted by 0.09nm from the Brillouin pump (BP). It has a peak power of −3dBm and a side-mode suppression ratio of 26dB. The BP wavelength is tunable within a wavelength range from 1562.5 to 1564nm. The BEFL has a narrow linewidth. It is suitable for many potential applications, such as optical communication and sensors.

L-Band Multiwavelength BEFL With Amplified Fiber Loop Mirror

An efficient L-band multiple-wavelength Brillouin-erbium fiber laser is presented. We configured a linear cavity resonator where the cavity ends are made up of high-reflectivity optical mirror on one side and an amplified fiber loop mirror on the other. This laser architecture provides amplification intensity-dependent transmission and allows the preamplification of the Brillouin pump (BP) signal before being injected into the Brillouin gain medium, i.e., the single-mode fiber (SMF). The technique ensures rapid reduction of erbium gain depletion, Brillouin gain saturation, and Brillouin threshold of the SMF thereby leading to the generation of higher number Brillouin Stokes lines. By utilizing only 8.5 dBm of the BP signal power, the proposed laser generates 54 Brillouin Stokes lines at BP signal wavelength of 1601.7 nm and 33 mW of the 1480-nm laser pump power. The generated channels are rigidly separated by 0.089 nm thereby becoming an attractive candidate to support the dense wavelength division multiplexing optical communication systems.

Spacing-Switchable Multiwavelength Fiber Laser Based on Nonlinear Polarization Rotation and Brillouin Scattering in Photonic Crystal Fiber

A new spacing-switchable multiwavelength erbium-doped fiber laser (EDFL) is demonstrated using switchable nonlinear polarization rotation (NPR) and stimulated Brillouin scattering (SBS) effects. The laser employs a 100-m-long photonic crystal fiber in conjunction with a four-port circulator in a figure-of-eight arrangement to provide the intensity-dependent transmission effect, as well as to discriminate the even-order and odd-order Brillouin Stokes to have a double-frequency Brillouin Stokes output. Without the Brillouin pump (BP), the laser operates in an NPR mode to produce at least 22 lasing wavelengths with a side mode suppression ratio of more than 10 dB and a wavelength spacing of 0.27 nm. In the Brillouin erbium fiber laser mode, at least 30 Brillouin lines with a spacing of 0.16 nm are obtained at BP power of 3 dBm and 980-nm pump power of 120 mW.