Graphene Saturable Absorber Research Articles

Passively mode-locked fiber laser by using monolayer chemical vapor deposition of graphene on D-shaped fiber.

We demonstrate a monolayer graphene saturable absorber (SA) based on D-shaped fiber for operation of the mode-locked fiber laser. The monolayer graphene is grown by chemical vapor deposition (CVD) on Cu substrate and transferred onto the polymer, and then covered with D-shaped fiber, which allows light-graphene interaction via the evanescent field of the fiber. Due to the side-coupled interaction, the length of graphene is long enough to avoid optical power-induced thermal damage. Using such a graphene-based SA, stable mode-locked solitons with 4.5 nm spectral bandwidth and 713 fs pulsewidth at the 1563 nm wavelength have been obtained under 280 mW pump power. The influence of total cavity dispersion on the optical spectrum and pulse is also investigated by adding different lengths of single-mode fiber in the laser cavity.

Nonadiabatic microfiber based mode‐locked erbium‐doped fiber laser using graphene

ABSTRACTA new compact and low threshold mode‐locked Erbium‐doped fiber laser (EDFL) using nonadiabatic microfiber in conjunction with a graphene saturable absorber is demonstrated. The graphene was synthesized by electrochemical exfoliation of graphite at room temperature in 1% sodium dodecyl sulfate aqueous solution. Graphene flakes obtained from the process are mixed with polyethylene oxide as the host polymer to produce composite solution which acts as passive mode locker in the EDFL linear cavity. Mode‐locked laser, with a threshold of less than 10 mW, pulse repetition rate of 55.8 MHz, and pulse duration of 0.82 ps, is achieved. The EDFL operates at around 1531.8 nm with an average output from 0.1 mW, pulse energy of 2 pJ at the 980 nm pump power of 10 mW. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:1670–1673, 2014

High-energy, tunable-wavelengths, Q-switched pulse laser

An all fiber, wavelength tunable, Q-switched erbium-doped fiber laser (EDFL) based on a graphene saturable absorber (SA) and an unbalanced Mach–Zehnder interferometer (UMZI) has been demonstrated. The wavelengths of the Q-switched laser can be accurately tuned over a range of ~35nm by inserting into the cavity an UMZI with a variable optical delay line (OVDL) in one arm, which acts as an optical beam filter into the cavity. The Q-switched pulse duration and the pulse energy have all been characterized. The maximum pulse energy of 36.9nJ was obtained.

Flexible graphene saturable absorber on two-layer structure for tunable mode-locked soliton fiber laser

Using a two-layer structure consisting of polyethylene terephthalate (PET) and polydimethylsiloxane (PDMS) to support graphene grown by chemical vapor deposition (CVD), we demonstrate a flexible integrated graphene saturable absorber (SA) on microfiber for passive mode-locked soliton fiber laser. This method can optimize the light-graphene interaction by using evanescent field in the integration structure. Moreover, the fiber laser with the in-line microfiber-to-graphene SA can realize the tunabilities of both the 3dB bandwidth of output optical spectrum and the pulse width of soliton. This tunable mode-locked soliton laser has potential applications in optical communication, optical microscopy, and so on.

Graphene saturable absorber for high power semiconductor disk laser mode-locking

Here, we report on the development of an antiresonant graphene-based one-dimensional structure which allows the control of linear and nonlinear device performance through optical confinement. A record average output in excess of 10 W is achieved by integrating this antiresonant graphene saturable absorber mirror into a vertical-external-cavity-surface-emitting-laser at 1030 nm, which leads to strong evidence of mode-locking, generating pulses with energies up to 2.8 nJ and a pulsewidth of 353 fs.

Passive synchronization of erbium and thulium doped fiber mode-locked lasers enhanced by common graphene saturable absorber

In this work we present for the first time, to the best of our knowledge, a passively synchronized thulium (Tm) and erbium (Er) doped fiber laser mode-locked by a common graphene saturable absorber (GSA). The laser consists of two ring resonators combined with a 90 cm long common fiber branch incorporating the saturable absorber (SA). Such laser generates optical solitons centered at 1558.5 nm and 1938 nm with pulse durations of 915 fs and 1.57 ps, respectively. Both laser loops were passively synchronized at repetition frequency of 20.5025 MHz by nonlinear interaction (cross phase modulation, XPM) in common fiber branch between generated pulses. The maximum cavity mismatch of the Er-laser in synchronization regime was 0.78 mm. The synchronization mechanism was also investigated. We demonstrate that the third order nonlinearities of graphene enhance the synchronization range. In our case the range was increased about 85%. The integrated RMS timing jitter between the synchronized pulses was 67 fs.

Passive Q-switched Erbium-doped fiber laser with graphene–polyethylene oxide saturable absorber in three different gain media

A Q-switched Erbium-doped fiber laser (EDFL) is proposed and demonstrated using graphene/polyethylene oxide thin film as a passive saturable absorber. The multi-layered graphene saturable absorber is incorporated into ring cavity of EDFL. Three different gain media are tested for the EDFL and they are 7 m long silica Erbium-doped fiber (EDF) with 400 ppm Erbium concentration, 4.5 m long EDF with 2,000 ppm Erbium concentration and 0.5 m long Bismuth EDF with 3,000 ppm Erbium concentration. The threshold pump powers for stable and seft-starting Q-switching are 33.7, 98.5 and 59.5 mW for 400, 2,000 and 3,000 ppm EDF, respectively. Corresponding pulse repetition rates are 24.2, 9.8 and 22.5 kHz at the threshold pump powers. The shortest pulse width of 2.48 μs is obtained with EDFL configured with 0.5 m long Bismuth EDF. The highest pulse energy of 40.69 nJ is obtained at pump power of 98.5 using 2,000 ppm silica EDF.

Simulations of a graphene excitable laser for spike processing

We propose and simulate a novel excitable laser employing passively \(Q\)-switching with a graphene saturable absorber for spike processing. Our approach combines the picosecond processing and switching capabilities of both linear and nonlinear optical device technologies to integrate both analog and digital optical processing into a single hardware architecture capable of computation without the need for analog-to-digital conversion. We simulate the laser using the Yamada model—a three-dimensional dynamical system of rate equations—and show behavior that is typical of spiking processing algorithms simulated in small circuits of excitable lasers.

A graphene-based passively Q-switched Ho:YAG laser in-band pumped by a diode-pumped Tm:YLF solid-state laser

We report the first demonstration of a Ho:YAG (yttrium aluminum garnet) solid-state laser passively Q-switched via a graphene saturable absorber. The Ho:YAG laser was in-band pumped by a continuous wave diode-pumped Tm:YLF (yttrium lithium fluoride) laser. Double-layer graphene grown by chemical vapor deposition and transferred onto a thin quartz plate was fabricated as the saturable absorber. We observed basically stable Q-switched laser pulses at the center wavelength of 2096.5 nm with the shortest pulse width of 632 ns, a repetition rate of 43 kHz, and the single-pulse energy of 13.3 μJ. Our results illustrate that graphene can be used well as a saturable absorber in a Ho-doped solid-state laser at 2 μm wavelength.

Pulse-Width Tuning in a Passively Mode-Locked Fiber Laser With Graphene Saturable Absorber

An absorption-adjustable graphene saturable absorber is used in a simple fiber laser system for an active control of the pulse-width of optical pulses. Such a saturable absorber is created by tightly attaching the graphene film onto the upper surface of the microfiber, thus an enhanced evanescence-field interaction between the propagating light along the microfiber length and graphene can be achieved. By tuning the polarization state of the light beam launched into the saturable absorber from TE to TM mode, the pulse-width of the pulses is varied between ~ 9.24 and ~ 2.32 ps.

Mode-locked thulium bismuth codoped fiber laser using graphene saturable absorber in ring cavity: reply

Jung and Lee have made comments [Appl. Opt.53, 553-554 (2014)] on "Mode-locked thulium bismuth codoped fiber laser using Graphene saturable absorber in ring cavity" [Appl. Opt.52, 1226-1229 (2013)]. The answer for the comment is provided in this report.

Mode-locked thulium-bismuth codoped fiber laser using graphene saturable absorber in ring cavity: comment

We comment on a recent paper [Appl. Opt.52, 1226 (2013)]. We believe that this paper reports significant errors regarding the autocorrelation measurement of output pulses and the associated analysis of their temporal and spectral characteristics.

Observations of three types of pulses in an erbium-doped fiber laser by incorporating a graphene saturable absorber: erratum

Observations of three types of pulses in an erbium-doped fiber laser by incorporating a graphene saturable absorber: erratum

Large-energy, narrow-bandwidth laser pulse at 1645 nm in a diode-pumped Er:YAG solid-state laser passively Q-switched by a monolayer graphene saturable absorber

Nonlinear transmission parameters of monolayer graphene at 1645 nm were obtained. Based on the monolayer graphene saturable absorber, a 1532 nm LD pumped 1645 nm passively Q-switched Er:YAG laser was demonstrated. Under the pump power of 20.8 W, a 1645 nm Q-switched pulse with FWHM of 0.13 nm (without the use of etalon) and energy of 13.5 μJ per pulse can be obtained. To the best of our knowledge, this is the highest pulse energy for graphene-based passively Q-switched Er:YAG laseroperating at 1645 nm, suggesting the potentials of graphene materials for high-energy solid-state laser applications.

Q-switched Er-doped fiber laser with low pumping threshold using graphene saturable absorber

We propose a Q-switched Er-doped fiber laser (EDFL) with a threshold pumping power as low as 7.4 mW, and demonstrate using graphene polyvinyl alcohol (PVA) thin film as a passive saturable absorber (SA). The SA is fabricated from graphene flakes, which is synthesized by electrochemical exfoliation of graphite at room temperature in 1% sodium dodecyl sulfate aqueous solution. The flakes are mixed with PVA solution to produce a thin film, which is then sandwiched between two ferrules to form a SA and integrated in the EDFL ring cavity to generate a stable Q-switched pulse train. The pulse train operates at 1560 nm with a threshold pump power of 7.4 mW. At maximum 1480 nm pump power of 33.0 mW, the EDFL generates an optical pulse train with a repetition rate of 27.0 kHz and pulse width of 3.56 μs. The maximum pulse energy of 39.4 nJ is obtained at a pump power of 14.9 mW. This laser can be used as a simple and low-cost light source for metrology, environmental sensing, and biomedical diagnostics.

Graphene Q-switched 0.9-\mu m Nd:La0.11Y0.89VO4 laser

Graphene saturable absorber (SA) is used as the passive Q-switcher of a 0.9-\mu m solid-state laser. When the laser medium is a Nd:La0.11Y0.89VO4 crystal, the initial transmittance of the graphene SA is 78%; at an absorbed pump power of 7.62 W, the maximum average output power, largest pulse energy, and minimum pulse width are 0.62 W, 2.58 ?J, and 84 ns, respectively. This study shows that graphene is a promising and cost-saving SA for 0.9-\mu m pulse generation.

A passively mode-locked intracavity frequency doubled Nd:YVO4 femtosecond green laser based on graphene

By using an atmospheric-pressure chemical vapor deposition (APCVD) method with a C2H2 carbon source, seven-layer graphene films as saturable absorbers are fabricated and transferred to an anti-reflective mirror of 1064 nm wavelength range. Based on this transmission-type graphene saturable absorber mirror (GSAM), a continuous wave (CW) passively mode-locked femtosecond green laser is achieved by 808 nm laser diode (LD) end-pumped Nd:YVO4 crystal and type-I critical phase-matched LBO crystal intracavity frequency doubling for the first time. Stable ultrashort green laser pulses as short as 374 fs are measured with a repetition rate of 71.4 MHz and an average output power of 117 mW at a central wavelength of 531.7 nm.

Observations of three types of pulses in an erbium-doped fiber laser by incorporating a graphene saturable absorber

We experimentally observed three types of pulses generated in an erbium-doped fiber laser by incorporating a homemade graphene saturable absorber (GSA). The generated pulses from the laser oscillator include dual-wavelength dark pulses, fundamentally step-like pulses, and non-soliton second-harmonic pulses. These operation regimes are first reported by using graphene as the saturable absorber. Our results will further indicate that the GSA can function well for obtaining various ultrafast pulse phenomena, highlighting the practical potential of graphene in ultrafast photonics technologies.

All-fiber dissipative soliton laser with 10.2 nJ pulse energy using an evanescent field interaction with graphene saturable absorber

We demonstrate a high-power dissipative soliton fiber laser by employing an evanescent field-coupled graphene saturable absorber (SA). In the SA, a polymer supporter enhances the nonlinear interaction between the guided mode and the high-quality graphene layers, which enables high-power operation of the mode-locked laser in the normal dispersion regime of the laser cavity. A self-started dissipative soliton fiber laser stably generates pulses with a spectral bandwidth of 10.4 nm at 1565 nm. The linearly chirped pulse of the laser output has a pulse duration of 13.8 ps at a repetition rate of 16.99 MHz. The maximum output power achieved is 174 mW using a single-mode pump laser diode with an applied power of 785 mW. The pulse energy is estimated to be 10.2 nJ; we believe this is the highest pulse energy ever reported for an Er-doped dissipative soliton fiber laser oscillator using a graphene SA.

A tunable, linearly polarized Er-fiber laser mode-locked by graphene/PMMA composite

An all-polarization maintaining, erbium-doped fiber laser based on a graphene saturable absorber is presented. The graphene layers were grown on copper foils by chemical vapor deposition (CVD) and transferred onto the fiber connector tip. The laser was capable of generating scalar solitons with sub-600 fs duration at 46 MHz repetition rate. The center wavelength of the emission could be continuously tuned from 1556 to 1560 nm by changing the intra-cavity losses. Thanks to the all-polarization maintaining cavity design the laser was self-starting, environmentally stable and could operate for long periods of time. The degree of polarization (DOP) of the output pulses was at the level of 99.8%.