Multiwavelength Brillouin-erbium Fiber Laser Research Articles

Double-Brillouin Frequency Spacing Multi-Wavelength Brillouin Erbium Fiber Laser in Double Cavities Configuration

Multi-wavelength fiber laser has great potential for use in dense wavelength-division multiplexing (DWDM) systems, sensors, and microwave photonics. This paper presents a multi-wavelength Brillouin erbium fiber laser (MW-BEFL) with double-frequency Brillouin spacing of approximately 0.176 nm between each adjacent Stokes. The proposed setup utilizes double cavities configuration for odd and even-order Brillouin Stokes to propagate separately in the system. This configuration is flexible as it can be transformed into a single-spacing MW-BEFL by swapping the ports of the circulator; it can also extract the odd-orders Brillouin Stokes by relocating the OSA in the cavity. Up to 25 double-spaced Brillouin Stokes are obtained with a tuning range of 30 nm. The first 8 Stokes have peak power variation within ± 3.7 dB and an average signal-to-noise ratio of 20 dB.

Tunable 60 GHz Multiwavelength Brillouin Erbium Fiber Laser

An experimental study of a tunable 60 GHz multiwavelength Brillouin erbium fiber laser is presented in this paper. Two unidirectional ring laser cavities and two pre-amplification laser cavities are used. In the first three cavities, a Brillouin gain medium is presented with a dispersion compensation fiber (DCF) spool, and a single-mode fiber (SMF) spool is used as a Brillouin gain medium in the fourth cavity. Three erbium amplifiers are utilized to supply enough gain to the generated Brillouin Stokes signal and to suppress cavity losses. For these three amplifiers, up to 450 mW (150 mW for each) of a 1480 nm pump power is used. In our proposed configuration, four sextuple Brillouin Stokes signals with a high power of 10 dBm and more than 55 dB as an optical signal-to-noise ratio are achieved. The obtained Brillouin Stokes signals can be tuned over 30 nm (1560–1590 nm) and can be easily used in dense wavelength division multiplexing in optics communication systems.

Q-switching pulse generation in multi-wavelength Brillouin Erbium-doped Fiber laser

Stimulated Brillouin scattering (SBS) was successfully used to induce Q-switching operation in a multi-wavelength Brillouin Erbium fiber laser (BEFL) operating in a long-wavelength band (L-band) regime. The SBS based self Q-switched laser used a 4.5 long highly nonlinear Erbium-doped fiber (EDF) as the hybrid gain medium to generate a multiple wavelength Q-switched pulses, which operated at the center wavelength of around 1603 nm. By changing the input pump power in a range from 59.1 mW to 162.2 mW, the repetition rate can be varied from 14.29 to 29.69 kHz and the pulse width can be grasped from 26.52 to 14.80 μs. Under 162.2 mW pump power, the maximum pulse energy was recorded at 96.0 nJ and the signal to noise ratio of the fundamental radio frequency was measured to be as high as 52.73 dB, which indicates the excellent stability of the SBS-based Q-switched laser. To the best of our knowledge, this is the first experiment of realizing a BEFL with Q-switched multi-wavelength output without any physical saturable absorber devices.

Switchable wide-band multi-wavelength fiber laser via Brillouin random lasing resonance

A switchable wide-band multi-wavelength Brillouin-erbium fiber laser constructed by a sub fiber loop (SFL) containing an erbium-doped fiber amplifier (EDFA) and a main fiber cavity (MFC) including a 1-km length of high nonlinear fiber (HNLF) via Brillouin random lasing resonance is proposed and experimentally investigated. The EDFA is incorporated into the sub fiber loop to boost optical power of the externally injected Brillouin pump (BP) light and Stokes wave fed back from the MFC, and the amplified BP light and Stokes wave are forward launched into the HNLF via the SFL, meanwhile, the generated Stokes wave is partially backward injected into the HNLF via the MFC, which make the Brillouin random lasing resonance of the Stokes wave form in the laser cavity. Using the proposed scheme, up to 19-orders backward-output Brillouin Stokes lines with a peak power discrepancy of less than 10 dB, and 281 stable forward-output Brillouin Stokes lines with a peak power discrepancy of less than 30 dB are obtained from the different output ports of the laser. Compared with the previous results, the backward generated Brillouin Stokes lines increase from 11 to 19 orders and the spectral-lines compositions also happen to change, and the forward generated stable Brillouin Stokes lines span over 30 nm and are extended by more than 18 nm. It is obvious that the generated Brillouin Stokes lines significant increasing should owe to the Brillouin random lasing resonance being introduced into the laser cavity. Influences of the system parameters including the BP power, EDFA pump power, and feedback power of Stokes wave on the laser lasing are investigated in detail. The proposed multi-wavelength fiber lasers can backward generate switchable Brillouin Stokes lines from 1st order to 19th order with an increasing wavelength number in turn, only by adjusting the EDFA pump power; moreover, the wavelength interval of the backward generated Brillouin Stokes lines can be switched between double- and single-Brillouin frequency shift, only by adjusting feedback power of the Stokes wave, without adding additional system configuration. A statistical analysis for the randomness of the multi-wavelength Brillouin-erbium fiber lasers is also done.

Tunable and narrow linewidth multi-wavelength Brillouin-erbium fiber laser using dual-wavelength pumping

Tunable and narrow linewidth multi-wavelength Brillouin-erbium fiber laser using dual-wavelength pumping

Generation of a multi-wavelength Brillouin erbium fiber laser with low threshold in multiple frequency spacing configurations

Brillouin fiber lasers are a promising optical source technology for industrial and academic purposes that have experienced continuous progress in recent years. Currently, part of this development is focused on proposing laser solutions with low resonator loss, relatively low pump threshold, high efficiency, small linewidth, and multi-wavelength architecture. In this context, we experimentally demonstrate the generation of a cascaded multi-wavelength Brillouin erbium fiber laser source with low threshold at multiple configurations. By employing a laser source of narrow linewidth and a fiber with high nonlinearity, compact all-fiber setups with low loss, single, double, and triple frequency spacing configurations are obtained using a Brillouin pump (BP) power as low as 1 mW. In these proposed configurations, we obtain up to 15, 15, and 11 Stokes channels within a 30 dB range and with frequency spacing between two adjacent lasing lines of 0.08 nm, 0.16 nm, and 0.32 nm, respectively. All laser source configurations investigated exhibit stable temporal behavior without prominent signs of wavelength shifts or power fluctuations. In this way, these multi-wavelength fiber laser sources demonstrated in this paper could be considered experimental and potential source to support dense wavelength division multiplexing systems.

Tunable Brillouin-erbium fiber laser producing multiwavelength cylindrical vector beams

A multiwavelength Brillouin-erbium fiber laser producing cylindrical vector beams with tunable central wavelength and wavelength spacing is presented and experimentally investigated. Owing to the inhomogeneous broadening characteristic of the Brillouin gain, stable multiwavelength lasing is achieved by combination of the cascaded stimulated Brillouin scattering in the ultra-long single mode fiber and the wavelength selection of the fiber Mach-Zehnder interferometer. Multiwavelength lasing with tunable wavelength spacing of about 0.09, 0.11, 0.17, 0.24 and 0.3 nm is achieved by adjusting the optical delay line in the Mach-Zehnder comb filter. With the sufficient pump power, multiwavelength lasing with more than 10 channels is obtained when the wavelength spacing is tuned to be about 0.09 nm. Through adjusting the flat-top tunable bandpass filter, the central lasing wavelength can be tuned from 1534.37 nm to 1570.06 nm continuously. Cylindrical vector beams with purity higher than 93% are produced through regulating polarization controllers on either side of the two-mode long-period grating serving as the mode convertor. Multiwavelength cylindrical vector beams with the largest number of channels and tuning range are obtained to the best of our knowledge.

A novel quadruple-spaced multiwavelength Brillouin-erbium fiber laser

We demonstrated a compact multiwavelength Brillouin-erbium fiber laser (MBEFL) with quadruple-Brillouin-frequency spacing. The quadruple-Brillouin-frequency spacing multiwavelength is generated mainly by utilizing two four-port circulators, two coils of single-mode fiber and two erbium gain modules. The generated multiwavelength spectra were investigated through adjusting the Brillouin pump (BP) and the 980 nm pumps. In the experiments, eight stable wavelengths were produced and the wavelength spacing was 0.348 nm (about 43.5 GHz) as the wavelength and the power of the BP were 5 mW and 1548.11 nm respectively, meanwhile the two 980 nm pumps’ powers were 470 mW and 520 mW respectively. The output multiwavelength can be tuned from 1546.12 nm to 1561.01 nm, and the maximum optical signal-to-noise ratio (OSNR) of the output channel was about 37 dB. The average OSNR of the stable multiwavelength was about 27 dB. The proposed stable and wider channel spaced MBEFL has diverse applications in dense wavelength division multiplexing optical communication, microwave photonics and fiber-optic sensors.

Tunable C + L bands triple frequency spacing multi-wavelength Brillouin-erbium fiber laser

We propose and experimentally demonstrate a wide tuning range triple frequency spacing multi-wavelength Brillouin erbium fibre laser (MBEFL). The laser can be tuned in the C- and L-bands of the optical communication windows. At a Brillouin pump power of 3 dBm and 1480-nm pump power of 195 mW, the proposed MBEFL generates up to five triple spacing Brillouin Stokes lines that can be tuned over 60 nm (from 1535 to 1595 nm). A wide tuning range is achieved through the combined techniques of pre-amplification and a virtual mirror of stimulated Brillouin scattering in the laser cavity. The generated Brillouin Stokes lines exhibit good flatness and stability with minimal power fluctuation.

Investigation of a tunable and switchable multi-wavelength bidirectional Brillouin-erbium fiber ring laser

A multi-wavelength bidirectional Brillouin-erbium fiber ring laser with switchable Brillouin frequency spacing (BFS) is proposed and experimentally demonstrated. In the presented Brillouin-erbium ring laser, including an optical amplifier and a highly nonlinear fiber, and without any optical isolator, due to Rayleigh scattering, stimulated Brillouin scattering, and cascaded four-wave mixing initiated successively by the Brillouin pump (BP) light, the odd- and even-order Stokes lines are generated and circulate in the opposite direction in the ring cavity. The BP light and Stokes-induced Rayleigh backscattering light also simultaneously circulate in the ring cavity. Only by adjusting BP power, the gain competition between Brillouin based Stokes and cavity modes’ oscillation can be controlled, the laser output can be conveniently switched between single BFS and odd- or even-order double BFS. In addition, under the certain BP power conditions, the proposed multi-wavelength Brillouin-erbium fiber laser also can realize switchable odd- or even-order Stokes generation and Stokes generation with single BFS, with an increasing wavelength number in turn, only by simply adjusting pump power of the erbium-doped fiber amplifier. Stability and wavelength tunability of the proposed multi-wavelength bidirectional Brillouin-erbium fiber ring laser are also investigated, respectively.

Widely triple Brillouin frequency shift multiwavelength Brillouin erbium fiber laser

We experimentally propose simple and widely tunable multiwavelength Brillouin erbium fiber laser with triple Brillouin frequency spacing. Only two dispersion compensation fiber spools with total length of 12 km, as a Brillouin gain media and erbium-doped fiber amplifier section with maximum pump power of 220 mW are utilized. In the developed structure, we achieved six triple Stokes lines with high peak power and large optical signal to noise ratio of more than 45 dB. Wide tuning range of 50 nm (1530–1580 nm) in the absence of self lasing cavity modes is recorded using both of high Brillouin pump and extracting the residual pump power outside the cavity.

Tunable 50 GHz laser comb generation of multiwavelength Brillouin erbium fiber laser

We experimentally proposed widely tunable multiwavelength Brillouin erbium fiber laser with quintuple Brillouin frequency spacing (∼ 0.4 nm, ∼ 50 GHz). Only three dispersion compensation fiber spools with total length of 15 km as a Brillouin gain media are used. Two sections of an erbium-doped fiber amplifier with maximum pump power of 220 mW are utilized. In the developed structure, at port1, we achieved four quintuple Stokes lines of about 10 dB peak power and large optical signal to noise ratio of more than 50 dB. Wide tuning range of 40 nm (1540–1580 nm) in the absence of free running modes is recorded using high BP power, BP pre-amplification, and extracting the residual pump power outside the cavity. In addition, another 14 quintuple Stokes channels are produced at another four output ports (port 2 to port 5). The whole generated 50 GHz wavelength spacing signals can be used in dense wavelength division multiplexing communication systems as such large channel spacing can be easily recognized by the optical detector at the receiver terminal.

Switchable Wide-Band Multi-Wavelength Brillouin-Erbium Fiber Laser Based on Random Distributed Feedback

A wavelength-interval switchable wide-band multi-wavelength Brillouin-erbium fiber laser with a half-open cavity is proposed and experimentally demonstrated, which is constructed by random distributed feedback (RDFB) mirrors provided by Rayleigh backscattering in a 1-km-long highly nonlinear fiber (HNLF) and a fiber loop mirror (FLM) incorporated a high-power erbium-doped fiber amplifier (HP-EDFA). A strong RDFB and high stimulated Brillouin scattering (SBS) gain are provided by the HNLF. The HP-EDFA is incorporated into the FLM to boost power of the Brillouin pump and feedback Stokes, enhanced SBS and multiple four-wave mixing are stimulated in the HNLF. Using the presented scheme, up to 118 stable Stokes laser lines with a power deviation of less than 15 dB, 70 stable Stokes laser lines with a power deviation of less than 5 dB and a fix wavelength spacing of 0.075 nm are obtained. Peak power fluctuations of arbitrarily chosen 27 Brillouin comb lines are less than 1.95 dB during a 60-minute measurement period, indicates that the proposed laser has a good stability. The effect of pump power of the HP-EDFA on Stokes generating in the laser is also investigated. Furthermore, when a polarization-maintaining fiber loop mirror is cascaded with the free end of the HNLF via an optical isolator, wavelength-interval switchable laser can be conveniently achieved.

Research on stability and uniformity of multi-wavelength Brillouin-erbium fiber laser based on FWM

In this paper, we experimentally and theoretically investigate the stability and uniformity of multi-wavelength Brillouin-erbium fiber laser based on four-wave mixing (FWM). Multi-wavelength generation is limited by cross-gain saturation between different wavelengths from homogeneous broadening of erbium-doped fiber. Modeling coupled-mode equation for FWM and analyzing the influence of FWM on multi-wavelength generation. 16 orders Brillouin Stokes (BS) waves with a wavelength spacing of 0.084 nm are obtained experimentally within a 3 dB bandwidth by the FWM effect in a 100 m highly nonlinear fiber (HNLF), power distribution of each laser is uniform and peak power fluctuation is less than 1.184 dB within a 10 dB bandwidth, the outputs exhibit good time stability and uniformity. Compared with the same configuration, the laser without HNLF has only 9 orders stable BS waves within 3 dB bandwidth, and high-order Stokes wave shows significant waveform jitter and power fluctuation.

Multi-wavelength Brillouin-erbium fiber laser with more than 95 lines based on a dual-ring structure

We demonstrate a multi-wavelength Brillouin fiber laser based on a dual-ring structure to take advantage of the forward and backward Brillouin gain simultaneously with an injected tunable scanning lasing. We used two erbium-doped fiber amplifiers for the amplification of the seed lasing and the operated Brillouin laser. The cascaded stimulated Brillouin effect in the section of dispersion-shifted fiber contributes to the free oscillation suppression in cavity. When the laser operates at the center wavelength of 1565 nm, the output spectra shows the maximum Brillouin lines of more than 95 with a wavelength spacing of about 0.08 nm under the maximum pump. Through adjusting of the seed wavelength and the tunable filter in cavity, the output spectra can be shifted from 1540 to 1570 nm. This fiber laser will find potential applications in optical measurement and sensing because of its large line number, stability, tunability and fixed wavelength spacing.

Tunable self-excited multiwavelength Brillouin-erbium fiber laser based on a variable temperature sensor

We propose and demonstrate a tunable self-excited multiwavelength Brillouin-erbium fiber laser based on a novel in-line Mach–Zehnder interferometer sensor (NMZIS) with variable temperature. The configuration of the NMZIS is a section of uncoated single-mode fiber sandwiched between an up-taper and multimode fiber. With the temperature changing from 30 °C to 90 °C, the transmission spectrum of the NMZIS shifts towards longer wavelengths. By embedding the NMZIS to act as a fiber filter in the ring cavity, the wavelength of the output multiwavelength comb is tuned from 1552.35 to 1564.48 nm. The corresponding generation of 21 Brillouin–Stokes lines with 25 dB optical signal-to-noise ratio is achieved.

Broadly tunable 40 GHz Brillouin frequency spacing multiwavelength Brillouin–Erbium fiber laser for DWDM

In this paper, we propose and experimentally demonstrate quadruple Brillouin-shift wavelength spacing (˜0.33 nm, ˜40 GHz) utilizing multiwavelength Brillouin–Erbium fiber laser (MBEFL) cavity. High Brillouin pump (BP) power, Pre-amplification technique, and capturing the residual pump power using wave selective coupler (WSC) are used to enhance laser comb tunability. The proposed structure has a tuning range of 60 nm (1530 nm–1590 nm) in the absence of self lasing cavity modes. Four stable Brillouin Stokes with high output power are achieved at 20mW and 225mW of BP and 1480 nm pump power respectively. In addition, multi-output ports with quadruple channel spacing is presented. This wide channel spacing make the proposed structure has strong potential to be used in dense wavelength division multiplexing (DWDM) communication systems.

Multiwavelength generation by using a novel Brillouin-erbium fiber laser with double linear-cavity based on a double-pass Brillouin Pump (BP) amplification technique

We propose and demonstrate an enhanced multiwavelength Brillouin-Erbium fiber laser by utilizing double linear cavity based on a double-pass pre-amplification technique. This simple structure is composed of two 24 km and 24.2 km single mode fiber (SMF) coils and two segments 13-m Erbium doped fibers (EDF). In order to obtain the Brillouin gain under low external injection Brillouin pump power, the BP is amplified in the linear cavity before entering into the SMF. In this experiment, so as to obtain the most Stokes lines, the optimization of 980 nm pump power and tunable laser source (TLS) power together with its corresponding wavelengths is very important. When setting the TLS power as 7.4 dBm and 980 nm pump power as 300 mW, a total of 51 Brillouin Stokes lines with frequency spacing of 0.089 nm are produced.

A Microwave Signal Generation Technique Based on Brillouin-Erbium Fiber Laser

An all-optical microwave signal generator based on multiwavelength Brillouin-Erbium fiber laser (MBEFL) is proposed. The MBEFL unit is designed at fixed wavelength spacing of 0.084 nm, which corresponds to ~10 GHz carrier signal. The underlying mechanism MBEFL unit is by recycling the backscattered Stokes waves into the cavity to generate higher-order Stokes waves. Heterodyning process is then applied to the Brillouin pump (BP) consisted of first-order Brillouin Stokes (BS1) (0.084 nm spacing) and second-order Brillouin Stokes (BS2) (0.168 nm spacing) signals by using a photodetector (PD). The heterodyned outputs are microwave signals at the frequencies of 10.56 GHz and 21.2 GHz, relative to first order and second order Stokes waves, respectively. These microwave signals are experimentally achieved by controlling the EDF pump power where the EDF pump power can be as low as 20 mW.

Wide tuning range and high OSNR self-seeded multi-wavelength Brillouin-erbium fiber laser based on a Lyot filter.

A tunable self-seeded multi-wavelength Brillouin-erbium fiber laser (BEFL) based on a Lyot filter is experimentally demonstrated in this paper. The Lyot filter is constructed by a polarization-dependent isolator (PDI), two polarization controllers (PCs), and a 20-cm-length polarization-maintaining fiber. In this proposed structure, the PDI is used as a polarizer. Due to the periodic filtering characteristics of the Lyot filter, the multi-wavelength output of the laser shows different Brillouin bands by adjusting the PCs. In the experiment, a single Brillouin band can be produced with the tuning range of 30nm, from 1527.8 to 1557.8nm. The optical signal-to-noise ratio (OSNR) of the output wavelengths is ∼20 dB. Dual Brillouin bands are observed.