High-power Erbium-doped Fiber Amplifier Research Articles

4.5 W mid-infrared light source based on acetylene-filled hollow-core fibers

We report here the characteristics of a continuous wave (CW) high-power mid-infrared (mid-IR) light source based on acetylene-filled anti-resonant hollow-core fiber (HCF). It is a single-pass configuration with 8 m HCFs, pumped by a high power erbium-doped fiber amplifier (EDFA). At the optimal gradient gas pressure of 3 mbar, a maximum power of 4.5 W at 3.1 μm is achieved, and the power conversion efficiency is ∼ 20% with respect to the absorbed pump power. It is, to the best of our knowledge, the highest output power for such mid-IR HCF lasers. This work demonstrate the great potential of fiber gas lasers for high-power output in the mid-IR.

Wideband optical frequency comb generation using a fiber re-circulating loop cascaded with a spectrum expander including highly nonlinear fiber

A wideband optical frequency comb (OFC) generator using a fiber re-circulating loop (FRL) including a phase modulator and optical amplifier, cascaded with a spectrum expander containing a high-power erbium-doped fiber amplifier and highly nonlinear fiber (HNLF) is proposed and experimentally demonstrated, in which the FRL is used as a source to generate seed comb lines, and then generated seed comb lines are extended to a wideband optical frequency comb using cascaded four-wave mixing in the HNLF. Only using one stage spectrum expander, a stable 20-GHz optical comb with 201 comb lines within 30-dB power deviation, spanning 40-nm bandwidth, is achieved. The results show that the HNLF has unique ability to broaden output spectrum from the FRL. In addition, an optical frequency comb is dramatically broadened, which may be predicted by optimizing gain and dispersion of the FRL or configuration of the spectrum expander, or both.

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.

Tunable and Switchable Multi-wavelength Erbium-Brillouin Random Fiber Laser Incorporating a Highly Nonlinear Fiber

A tunable and switchable multi-wavelength Erbium–Brillouin random fiber laser (MW-EBRFL) with a half-open cavity structure and incorporating a segment of highly nonlinear fiber (HNLF) is proposed and experimentally demonstrated. Due to HNLF being with high nonlinear coefficient, high Brillouin gain coefficient and high Rayleigh scattering (RS) coefficient, a reduced length of HNLF can provide a strong random distributed feedback (RDFB) and high stimulated Brillouin scattering (SBS) gain. In addition, an optical fiber amplify loop (OFAL) including a high-power erbium-doped fiber amplifier (HP-EDFA) and an optical attenuator (ATT) is constructed to provide a strong Brillouin pump (BP) and controllable optical feedback. Using the presented MW-EBRFL, up to 11 orders of stable Stokes laser lines with a wavelength spacing of 0.074 nm and the minimum optical signal-to-noise ratio (OSNR) of 41.22 dB are obtained. System parameters including BP power and HP-EDFA pump power influence on output of MW-EBRFL are also investigated. By adjusting BP wavelength, multi-wavelength output with 6–11 channel numbers can be tuned in a wide wavelength range spanning 36 nm. The proposed MW-EBRFL also can realize switchable multi-wavelength generation of 1 ∼ 11 order Stokes with an increasing wavelength number in turn, only by simply adjusting HP-EDFA pump power. Furthermore, when a polarization-maintaining fiber loop mirror filter (PMF-LMF) is cascaded with output port of the cavity, it can be very convenient to achieve wavelength switching between single- and double-Brillouin frequency spacing (BFS), only by tuning polarization controller in PMF-LMF.

Mid-infrared 1 W hollow-core fiber gas laser source.

We report the characteristics of a 1W hollow-core fiber gas laser emitting CW in the mid-IR. Our system is based on an acetylene-filled hollow-core optical fiber guiding with low losses at both the pump and laser wavelengths and operating in the single-pass amplified spontaneous emission regime. Through systematic characterization of the pump absorption and output power dependence on gas pressure, fiber length, and pump intensity, we determine that the reduction of pump absorption at high pump flux and the degradation of gain performance at high gas pressure necessitate the use of increased gain fiber length for efficient lasing at higher powers. Low fiber attenuation is therefore key to efficient high-power laser operation. We demonstrate 1.1W output power at a 3.1μm wavelength by using a high-power erbium-doped fiber amplifier pump in a single-pass configuration, approximately 400 times higher CW output power than in the ring cavity previously reported.

Femtosecond Er-doped fiber laser based on divided-pulse nonlinear amplification

A high-power erbium-doped fiber amplifier was realized by using a spatially and temporally divided pulse amplification technique. Pulse amplification and compression were simultaneously achieved in a double-clad Er-doped fiber by controlling the pulse gain and dispersion, generating a slope efficiency of 19.2% for the divided pulse amplification. The spectrum and pulse evolutions for nonlinear amplification and compression in the double-clad gain fiber were studied both in theory and experiment. Then 680 mW near-infrared femtosecond laser pulses were obtained by using 0.45 m single-mode fiber to compress amplified pulses. Frequency doubling was further carried out with a periodically poled lithium niobate (PPLN) crystal, generating 790 nm laser pulses with 110 mW average power and 95.7 fs pulse duration.

Design of optical time-division multiplexed systems using the cascaded four-wave mixing in a highly nonlinear photonic crystal fiber for simultaneous time demultiplexing and wavelength multicasting

This paper reports a new design of optical time-division multiplexed (OTDM) systems that possess a functionality of simultaneous time demultiplexing and wavelength multicasting based on the cascaded four-wave mixing in a dispersion-flattened highly nonlinear photonic crystal fiber (DF-HNL-PCF). A module of OTDM demultiplexing and wavelength multicasting can be feasibly implemented by using a 3 dB optical coupler, a high-power erbium-doped fiber amplifier, a short-length DF-HNL-PCF, and a wavelength demultiplexer in the simple configuration. We also carry out an experiment on the proposed system to demonstrate the 100–10 Gbit s−1 OTDM demultiplexing with wavelength conversion simultaneously at 4 multicast wavelengths. It is shown that error-free wavelength multicasting is achieved on two wavelength channels with the minimum power penalty of 3.2 dB relative to the 10 Gbit s−1 back-to-back measurement, whereas the bit error rates of other two multicasting channels are measured to be about 10−6–10−5. Moreover, we propose the use of a proper error-correcting code to improve the multicasting performance of such an OTDM system, and our work reveals that the resulting system can theoretically support error-free multicasting of the OTDM-demultiplexed signal on four wavelength channels.

Multi-wavelength fiber laser based on self-seed light amplification and wavelength-dependent gain

In this paper, a multi-wavelength fiber laser based on self-seed light amplification and wavelength-dependent gain is proposed and demonstrated. A pumped erbium-doped fiber (EDF) in the linear cavity acts as the seed light source, which is also conducive to the gain equalization. A high power erbium-doped fiber amplifier (EDFA) is deployed for self-seed amplification, and a highly nonlinear fiber (HNLF) is incorporated in the ring cavity to alleviate the mode competition induced by the homogeneous gain broadening of EDF. In the experiments, 25-wavelength operation within 0.5dB uniformity is achieved with the extinction ratio of ~42dB using 500m HNLF, and 38-wavelength operation within 3dB uniformity is obtained with the extinction ratio of ~35dB using 1000m HNLF. Our proposed laser has more lasing wavelengths with a better uniformity and stability.

Unrepeatered Transmission of 6.3 Tb/s ( \(63 \times 128\) Gb/s) Over 402-km Fiber Link

We demonstrated 6.3-Tb/s (63 × 128 Gb/s) unrepeatered transmission over 402-km fiber link. This was achieved by employing a high-power Yb-free clad-pumped L-band erbium-doped fiber amplifier (EDFA) as a booster amplifier in the transmitter station, a combination of ultralarge-area fiber, low loss and zero-water-peak loss fibers, and a remote optically pumped amplifier (ROPA), which was counter-propagating second-order Raman pumped from receiver station. This letter also describes the design and characteristics of Yb-free cladpumped L-band EDFA, and discusses the system performance optimization of ROPA and Raman impact on large capacity long reach unrepeatered transmission.

All-fiber laser generating at 3.8 μm pumped by 1565 nm fiber laser and the second-order laser at 1.9 μm

We propose an all-fiber source at 3.8 μm with a high Tm-doped fiber as the gain medium pumped by a 1565-nm high-power fiber laser. With a laser diode at 1565 nm amplified by a high power erbium-doped fiber amplifier injecting into a segment of Tm-doped fiber, a fiber laser at 3.8 μm generates. Simultaneously, a second-order laser at 1.9 μm (dual-frequency of 3.8 μm) can be observed clearly. The laser has a threshold pump power of ∼300 mW and generates more than 176 mW continuous-wave output power with 1560 mW pump power. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:848–850, 2014

Stabilized 51-wavelength erbium-doped fiber ring laser based on high nonlinear fiber

A multi-wavelength fiber laser source is demonstrated with a high power erbium-doped fiber amplifier as the gain medium. In order to alleviate the mode competition, a highly nonlinear fiber (HNLF) is inserted in the ring cavity to provide nonlinear effects. A fiber Fabry–Perot filter (FFPF) is incorporated in the ring cavity serving as a comb filter. The comparison between HNLF with different length is discussed. Fifty one simultaneous lasing wavelengths within 3dB uniformity are observed with channel spacing of 25GHz and a signal to noise ratio of ~48dB. Moreover, these stable multi-carriers light source is a promising candidate for high capacity optical communication system, such as coherent dense-wavelength-multiplexing (DWDM) in our project.

Polarization Insensitive Wavelength Conversion by FWM of Multiformat DWDM Signals Using Birefringent PCF

We demonstrate all-optical wavelength conversion of four channels of polarization scrambled 10 Gb/s dense wavelength division multiplexed signals consisting of both nonreturn-to-zero-ON-OFF-keyed and differential-phase-shift keyed signals using 20 m of nonlinear birefringent photonic crystal fiber (PCF). Power penalties <;0.5 dB were achieved for a conversion bandwidth of 22 nm with four-wave mixing efficiencies between -20 and -24 dB. A rack-mount wavelength converter prototype is presented that consists of a highly tunable sample grating distributed Bragg reflector pump laser, a high-power erbium-doped fiber amplifier, a tunable bandpass filter, and a polarization controller that are all controlled using a microcontroller. Automatic polarization control of the high-power pump is demonstrated for the first time using the polarization dependence of stimulated Brillouin scattering in the PCF as a feedback mechanism.

High-power EDFA applied in distributed optical fiber Raman temperature sensor system

In this paper, a high-power erbium-doped fiber amplifier (EDFA) for the temperature sensor system is theoretically designed and experimentally demonstrated. It consists of an erbium-doped fiber that is pumped bidirectionally with two 980-nm high-power laser diodes (LDs). At the EDFA input, an optical isolator (ISO) is used to ensure that the signal pulse transmits forward only. After that, a wavelength division multiplexer (WDM) is employed to combine the forward pump laser (980 nm) and incident optical pulse (1550 nm) into the erbium-doped fiber for direct amplification in the optical domain. At the EDFA output, another WDM couples the backward pump laser (980 nm) into the erbium-doped fiber and outputs the amplified optical pulse (1550 nm) with an ISO followed to isolate the backscattering light. According to this structure, we carried out the experiment in the condition as follows. For 980 nm pump LD, the operating current is 590 mA, and the setting temperature is 25°C. For EDFA, the length of erbium-doped fiber is 12.5 m, and the power of 1550 nm input signal is 1.5mW. As a result, the power of pump LD is 330mW, and the power uncertainty is 0.5%. The power of EDFA output at 1550 nm is 300mW, and the power uncertainty is ± 3mW.

Fiber-optic parametric amplifier and oscillator based on intracavity parametric pump technique

A cost-effective fiber optical parametric amplifier (FOPA) based on the laser intracavity pump technique has been proposed and demonstrated experimentally. The parametric process is realized by inserting a 1 km highly nonlinear dispersion-shifted fiber (HNL-DSF) into a fiber ring-laser cavity that consists of a high-power erbium-doped fiber (EDF) amplifier and two highly reflective fiber Bragg gratings. Compared with the conventional parametric pump schemes, the proposed pumping technique is free from a tunable semiconductor laser as the pump source and also the pump phase modulation. When the oscillating power of 530 mW in the EDF laser cavity is achieved to pump the HNL-DSF, a peak parametric gain of 27.5 dB and a net gain over 45 nm are obtained. Moreover, a widely tunable fiber-optic parametric oscillator is further developed using the FOPA as a gain medium.

Failure Analysis Using Optical Evaluation Technique (OBIC) of LDs for Fiber Optical Communication

AbstractThe introduction of high-speed services for fiber-optic access subscribers has led to a huge growth in data traffic. The rapid diversification of services means that next generation networks must be built quickly, economically and reliably.A high temperature laser allows us to eliminate the thermo-electric cooler conventionally needed in a transmitter module, which results in reductions in cost, power consumption and size. Moreover, a high-power laser provides a wide tolerance when coupling optical fibers. In addition, a high-power pump laser is needed to realize a wide-band and high-power erbium-doped fiber amplifier. This makes high-performance laser chips one of the keys to achieving highly reliable and cost-effective systems.In terms of laser reliability, we must clarify the degradation mechanism and postpone or suppress degradation if we are to achieve a reliable high-performance laser. We have analyzed degraded lasers using the optical beam induced current (OBIC) technique. When there are nonradiative recombination centers in the degraded region, the OBIC intensity decreases with increases in recombination density. This technique has the advantages of being non-destructive and highly sensitive. In addition, it provides high space resolution in degradation analyses.The OBIC is measured through the window of a transistor outline (TO) can before and after aging. Then, by using the same LDs we can detect an OBIC change for several aging times. We can both detect the degraded region and layer, and estimate the degree of laser degradation by employing the relative OBIC intensity prior to aging. This OBIC technique is useful for analyzing the degree of laser degradation.Moreover, the incident wavelength can be changed by changing the optical source in the OBIC measurement setup, which in turn changes the absorption layer and the penetration distance. Some degraded laser layers are reveled by using these several wavelengths absorbed in different layers. In addition, degradation in the waveguide interior is detected by using an incident wavelength with long penetration. Thus, by monitoring the OBIC intensity at several wavelengths as well as before and after aging, we are able to discuss sudden and wear-out laser failures. In our presentation, we will introduce examples using the OBIC technique that contributed to the improvement of laser reliability.

Resonantly pumped high power flat L-band erbium-doped superfluorescent fiber source

An all-single-mode-fiber L-band superfluorescent fiber source (SFS) with 1 W output power, 34.3 nm bandwidth (FWHM) and 54% optical conversion efficiency is constructed by seeding a high power erbium-doped fiber amplifier (EDFA) with a low power L-band ASE seed source to avoid parasitic lasing. The source is resonantly pumped by a high power C-band SFS peaked at 1545 nm.

Noise penalty of highly saturated erbium-doped fiber amplifiers in analog links

We outline the noise penalty of using a high-power erbium-doped fiber amplifier in the place of a shot-noise-limited laser for analog applications. Intensity noise measurements are presented using a highly saturated +22-dBm output-power amplifier, demonstrating the achievable signal-to-noise ratios when passive optical loss follows the amplification stage.

Room temperature multiwavelength erbium-doped fiber ring laser using a highly nonlinear photonic crystal fiber

A multiwavelength laser source is demonstrated with a high power erbium-doped fiber amplifier as the gain medium. A highly nonlinear photonic crystal fiber (PCF) is inserted in the ring cavity to provide nonlinear gain by four-wave mixing. A Sagnac loop is incorporated in the ring cavity serving as a comb-like multichannel filter. The comparison between fiber ring laser without PCF and with PCF shows that the highly nonlinear PCF can generate a larger number of excited wavelengths and help stabilize the output power.

Single-mode pumping scheme for EDFA with high-power conversion efficiency using a 980-NM Ti:S laser

In this paper, we demonstrate a high-power erbium-doped fiber amplifier pumped by single-mode titanium sapphire (Ti:S) laser at 980 nm. The highest output power of 22.6 dBm is measured at 1549 nm with an input signal power of 4 dBm and a pump power of 300 mW. This corresponds to power-conversion efficiency (PCE) of 60, providing 95 quantum efficiency. The experimental results show the feasibility of using a single-mode laser from a high-power semiconductor chip to produce high-efficiency booster amplifiers. (c) 2005 Wiley Periodicals, Inc.

FiberVista: An FTTH or FTTC system delivering broadband data and CATV services

FiberVista is a fiber-to-the-home (FTTH) or fiber-to-the-curb (FTTC) system that provides more bandwidth for emerging broadband services, such as Internet data, than existing deployed residential systems, while tapping predictable revenue streams from telephony and analog- and digital-video broadcast television service. At the same time, FiberVista minimizes development costs by reusing existing or emerging technology from other systems, such as cable modems and low-cost residential optical transceivers. It also allows for incremental, “pay-as-you-grow” provisioning of capacity. Like cable-television (CATV) hybrid fiber-coax (HFC) networks, FiberVista uses subcarrier multiplexing to offer a flexible mix of services. The system is superior to HFC in that it offers more total bandwidth, both upstream and downstream, which can be shared among fewer homes. By limiting the coax plant to a small passive run in FTTC, or eliminating it altogether in FTTH, FiberVista minimizes the most unreliable and maintenance-intensive portion of the HFC network. Furthermore, it utilizes new technologies, such as high-power erbium-doped fiber amplifiers (EDFAs), coarse wavelength division multiplexing (CWDM), and passive optical networks (PONs), to make the extension of optical fiber deep into the network practical. In this paper, we describe the FiberVista network architecture, potential upgrade scenarios, and experimental system demonstrations.