Showing papers on "Fiber laser published in 2011"
06 Mar 2011
TL;DR: In this paper, the concept of a fiber laser with an open cavity that operates using random distributed feedback provided by Rayleigh scattering amplified through the Raman effect is discussed, and the results of ultra-long laser experiments are discussed.
Abstract: I will overview our recent results on ultra-long lasers and will discuss the concept of a fiber laser with an open cavity that operates using random distributed feedback provided by Rayleigh scattering amplified through the Raman effect.
779 citations
TL;DR: In this article, a wideband-tunable Q-switched fiber laser exploiting a graphene saturable absorber was demonstrated, with 2μs pulses, tunable between 1522 and 1555 nm.
Abstract: We demonstrate a wideband-tunable Q-switched fiber laser exploiting a graphene saturable absorber. We get ∼2 μs pulses, tunable between 1522 and 1555 nm with up to ∼40 nJ energy. This is a simple and low-cost light source for metrology, environmental sensing, and biomedical diagnostics.
436 citations
TL;DR: In this article, the intrinsic properties of monolayer graphene allow it to act as a more effective saturable absorber for mode-locking fiber lasers when compared to multilayer graphene.
Abstract: We demonstrate that the intrinsic properties of monolayer graphene allow it to act as a more effective saturable absorber for mode-locking fiber lasers when compared to multilayer graphene. The absorption of monolayer graphene can be saturated at lower excitation intensity compared to multilayer graphene, graphene with wrinkle-like defects, or functionalized graphene. Monolayer graphene has a remarkably large modulation depth of 65.9%, whereas the modulation depth of multilayer graphene is greatly reduced due to nonsaturable absorption and scattering loss. Picosecond ultrafast laser pulses (1.23 ps) can be generated using monolayer graphene as a saturable absorber. Due to the ultrafast relaxation time, larger modulation depth and lower scattering loss of monolayer graphene, it performs better than multilayer graphene in terms of pulse shaping ability, pulse stability, and output energy.
406 citations
TL;DR: A series of new data processing and imaging extraction protocols, enabled by the ultrawide-field isotropic data sets, are presented, which enable both, cross-sectional images along arbitrary coordinates and depth-resolved en-face fundus images.
Abstract: We demonstrate ultrahigh speed swept source retinal OCT imaging using a Fourier domain mode locked (FDML) laser. The laser uses a combination of a semiconductor optical amplifier and an ytterbium doped fiber amplifier to provide more than 50mW output power. The 1050nm FDML laser uses standard telecom fiber for the km long delay line instead of two orders of magnitude more expensive real single mode fiber. We investigate the influence of this “oligo-mode” fiber on the FDML laser performance. Two design configurations with 684,400 and 1,368,700 axial scans per second are investigated, 25x and 50x faster than current commercial instruments and more than 4x faster than previous single spot ophthalmic results. These high speeds enable the acquisition of densely sampled ultrawide-field data sets of the retina within a few seconds. Ultrawide-field data consisting of 1900 x 1900 A-scans with ~70° degrees angle of view are acquired within only 3 and 6 seconds using the different setups. Such OCT data sets, more than double as large as previously reported, are collapsed to a 4 megapixel high definition fundus image. We achieve good penetration into the choroid by hardware spectral shaping of the laser output. The axial resolution in tissue is 12µm (684kHz) and 19µm (1.37MHz). A series of new data processing and imaging extraction protocols, enabled by the ultrawide-field isotropic data sets, are presented. Dense isotropic sampling enables both, cross-sectional images along arbitrary coordinates and depth-resolved en-face fundus images. Additionally, we investigate how isotropic averaging compares to the averaging of cross-sections along the slow axis.
332 citations
TL;DR: In this contribution the important developments in the field of Er-doped integrated waveguide amplifiers and lasers are reviewed and current and future potential applications are explored.
Abstract: Erbium-doped fiber devices have been extraordinarily successful due to their broad optical gain around 1.5–1.6 μm. Er-doped fiber amplifiers enable efficient, stable amplification of high-speed, wavelength-division-multiplexed signals, thus continue to dominate as part of the backbone of longhaul telecommunications networks. At the same time, Er-doped fiber lasers see many applications in telecommunications as well as in biomedical and sensing environments. Over the last 20 years significant efforts have been made to bring these advantages to the chip level. Device integration decreases the overall size and cost and potentially allows for the combination of many functions on a single tiny chip. Besides technological issues connected to the shorter device lengths and correspondingly higher Er concentrations required for high gain, the choice of appropriate host material as well as many design issues come into play in such devices. In this contribution the important developments in the field of Er-doped integrated waveguide amplifiers and lasers are reviewed and current and future potential applications are explored. The vision of integrating such Er-doped gain devices with other, passive materials platforms, such as silicon photonics, is discussed.
301 citations
TL;DR: A highly sensitive compact hydrophone, based on a pi-phase-shifted fiber Bragg grating, has been developed for the measurement of wideband ultrasonic fields, which makes the design attractive for medical imaging applications, such as optoacoustic tomography, in which compact, sensitive, and wideband acoustic detectors are required.
Abstract: A highly sensitive compact hydrophone, based on a pi-phase-shifted fiber Bragg grating, has been developed for the measurement of wideband ultrasonic fields. The grating exhibits a sharp resonance, whose centroid wavelength is pressure sensitive. The resonance is monitored by a continuous-wave (CW) laser to measure ultrasound-induced pressure variations within the grating. In contrast to standard fiber sensors, the high finesse of the resonance--which is the reason for the sensor's high sensitivity--is not associated with a long propagation length. Light localization around the phase shift reduces the effective size of the sensor below that of the grating and is scaled inversely with the resonance spectral width. In our system, an effective sensor length of 270 μm, pressure sensitivity of 440 Pa, and effective bandwidth of 10 MHz were achieved. This performance makes our design attractive for medical imaging applications, such as optoacoustic tomography, in which compact, sensitive, and wideband acoustic detectors are required.
234 citations
TL;DR: A dual-wavelength passively mode-locked soliton fiber laser based on the single-wall carbon nanotube saturable absorber that is able to simultaneously generate sub-picosecond pulses at both ~1532 and 1557 nm wavelength is demonstrated.
Abstract: We demonstrate a dual-wavelength passively mode-locked soliton fiber laser based on the single-wall carbon nanotube saturable absorber. By using a simple scheme of adjusting the intracavity loss, the gain profile of the erbium-doped fiber laser is effectively controlled. Besides operating at a single wavelength, the laser is able to simultaneously generate sub-picosecond pulses at both ~1532 and 1557 nm wavelength. The mode-locking wavelength can also be quickly switched from one wavelength to the other by changing the intracavity loss with a tunable attenuator.
222 citations
TL;DR: In this paper, a simple method for the in-situ monitoring of the deposition of few-layers graphene in an optical fiber end by mechanical exfoliation is presented.
Abstract: Graphene exhibits wavelength-independent, saturable optical absorption with fast response time, and large modulation depth. Thus, it is an attractive material for the saturable absorption of fiber lasers. In this paper, we report a simple method for the in-situ monitoring of the deposition of few-layers graphene in an optical fiber end by mechanical exfoliation. Saturable absorbers with different number of graphene layers (from 4 layers of graphene to few 10 s of layers) are prepared and low threshold, self-starting passive mode-locked operation of a fiber laser with sub-picosecond pulse duration is demonstrated.
221 citations
TL;DR: In this article, the authors presented a random fiber laser that is tunable over a broad wavelength range with uniquely flat output power and high efficiency, which outperforms traditional lasers of the same category.
Abstract: An optical fiber is treated as a natural one-dimensional random system where lasing is possible due to a combination of Rayleigh scattering by refractive index inhomogeneities and distributed amplification through the Raman effect. We present such a random fiber laser that is tunable over a broad wavelength range with uniquely flat output power and high efficiency, which outperforms traditional lasers of the same category. Outstanding characteristics defined by deep underlying physics and the simplicity of the scheme make the demonstrated laser a very attractive light source both for fundamental science and practical applications.
215 citations
TL;DR: To the best of the knowledge, this is the first report for passively Q-switched sub-100-ns pulse operation of a graphene-based saturable absorber in a Yb-doped fiber laser.
Abstract: We demonstrate stable 70 ns pulse generation from a Yb-doped fiber laser passively Q-switched by a graphene-based saturable absorber mirror in a short linear cavity. The maximum output power was 12 mW and the highest single pulse energy was 46 nJ. The repetition rate of the fiber laser can be widely tuned from 140 to 257 kHz along with the increase of the pump power. To the best of our knowledge, this is the first report for passively Q-switched sub-100-ns pulse operation of a graphene-based saturable absorber in a Yb-doped fiber laser.
210 citations
TL;DR: It is demonstrated that the supercontinuum is compressible to a duration of 26 fs, and has a high degree of coherence between all the frequency components, and is a single pulse in the time domain.
Abstract: We demonstrate supercontinuum generation in a photonic crystal fiber with all-normal group velocity dispersion. Pumping a short section of this fiber with compressed pulses from a compact amplified fiber laser generates a 200 nm bandwidth continuum with typical self-phase-modulation characteristics. We demonstrate that the supercontinuum is compressible to a duration of 26 fs. It therefore has a high degree of coherence between all the frequency components, and is a single pulse in the time domain. A smooth, flat spectrum spanning 800 nm is achieved using a longer piece of fiber.
TL;DR: This paper reports all-fiber laser operation with fundamental repetition rates of 4.24 GHz, 9.63 GHz and 19.45 GHz, which is, to date and to the best of the authors' knowledge, the highest fundamental repetition rate reported for an all-Fiber laser.
Abstract: There is an increasing demand for all-fiber passively mode-locked lasers with pulse repetition rates in the order of gigahertz for their potential applications in fields such as telecommunications and metrology. However, conventional mode-locked fiber lasers typically operate at fundamental repetition rates of only a few megahertz. In this paper, we report all-fiber laser operation with fundamental repetition rates of 4.24 GHz, 9.63GHz and 19.45GHz. This is, to date and to the best of our knowledge, the highest fundamental repetition rate reported for an all-fiber laser. The laser operation is based on the passive modelocking of a miniature all-fiber Fabry-Perot laser (FFPL) by a carbon nanotube (CNT) saturable absorber. The key components for such device are a very high-gain Er:Yb phosphosilicate fiber and a fiber compatible saturable absorber with very small foot print and very low losses. The laser output of the three lasers was close to transform-limited with a pulsewidth of approximately 1ps and low noise. As a demonstration of potential future applications for this laser, we also demonstrated supercontinuum generation with a longitudinal mode-spacing of 0.08nm by launching the laser operating at 9.63GHz into 30m of a highly nonlinear dispersion shifted fiber.
TL;DR: A maximum output power of 20.6 W at 2.825 μm from an erbium-doped all-fiber laser is reported, which is believed to be the highest output power for this laser transition in single-mode operation and the first experimental confirmation of the predicted pump energy recycling for this fiber laser.
Abstract: A maximum output power of 20.6 W at 2.825 μm from an erbium-doped all-fiber laser is reported, which we believe is the highest output power for this laser transition in single-mode operation. The slope efficiency of the passively cooled laser was up to 35.4% with respect to the absorbed pump power. Accounting for an estimated round-trip intracavity loss of 1.3 dB, we calculated a theoretical conversion efficiency of 39.5%, which is 15% higher than the Stokes efficiency of 34.3%. We believe this is the first experimental confirmation of the predicted pump energy recycling for this fiber laser. The narrow laser linewidth varied from 0.09 to 0.16 nm from low to maximum output power.
TL;DR: A compact, low-noise, single-frequency fiber laser by using a newly developed Yb³⁺ heavily doped single-mode phosphate glass fiber has been demonstrated.
Abstract: A compact, low-noise, single-frequency fiber laser by using a newly developed Yb³⁺ heavily doped single-mode phosphate glass fiber has been demonstrated Over 400 mW stable continuous wave single transverse and longitudinal mode laser at 106 μm was achieved from a 08 cm long active fiber The measured slope efficiency and estimated quantum efficiency of laser emission are 727% and 93%, respectively The signal-to-noise ratio is higher than 72 dB, and the linewidth of the fiber laser is less than 7 kHz, while the measured relative intensity noise is less than -130 dB/Hz at frequencies of over 15 MHz
TL;DR: The incoherent beam combination of the four narrow-linewidth fiber amplifier chains running at different wavelengths using a polarization-independent dielectric reflective diffraction grating mainly preserving the beam quality of the individual fiber amplifiers.
Abstract: We report on the incoherent beam combination of the four narrow-linewidth fiber amplifier chains running at different wavelengths Each main amplifier stage consists of a large-mode-area photonic crystal fiber delivering more than 2 kW of optical power The four output beams are spectrally combined to a single beam with an output power of 82 kW using a polarization-independent dielectric reflective diffraction grating mainly preserving the beam quality of the individual fiber amplifiers
TL;DR: This work studies numerically rogue waves in dissipative systems, taking as an example a unidirectional fiber laser in a nonstationary regime of operation and finding that the probability of producing extreme pulses in this setup is higher than in any other system considered so far.
Abstract: We study numerically rogue waves in dissipative systems, taking as an example a unidirectional fiber laser in a nonstationary regime of operation. The choice of specific set of parameters allows the laser to generate a chaotic sequence of pulses with a random distribution of peak amplitudes. The probability density function for the intensity maxima has an elevated tail at higher intensities. We have found that the probability of producing extreme pulses in this setup is higher than in any other system considered so far.
TL;DR: Measurements confirm that energy transfer between the fluctuating transversal modes takes place in millisecond-time-scale.
Abstract: A high-speed mode analysis technique is required to gain fundamental understanding of mode instabilities in high-power fiber laser systems. In this work a technique, purely based on the intensity profile of the beam, is demonstrated to be ideally suited to analyze fiber laser dynamics. This technique, together with a high-speed camera, has been applied to the study of the temporal dynamics of mode instabilities at high average powers with up to 20,000 frames per second. These measurements confirm that energy transfer between the fluctuating transversal modes takes place in millisecond-time-scale.
TL;DR: In this paper, a mid-IR supercontinuum (SC) fiber laser based on a thulium-doped fiber amplifier (TDFA) is demonstrated with a continuous spectrum extending from ∼1.9 to 4.5 μm.
Abstract: A mid-IR supercontinuum (SC) fiber laser based on a thulium-doped fiber amplifier (TDFA) is demonstrated. A continuous spectrum extending from ∼1.9 to 4.5 μm is generated with ∼0.7 W time-average power in wavelengths beyond 3.8 μm. The laser outputs a total average power of up to ∼2.6 W from ∼8.5 m length of ZrF4─BaF2─LaF3─AlF3─NaF (ZBLAN) fiber, with an optical conversion efficiency of ∼9% from the TDFA pump to the mid-IR SC. Optimal efficiency in generating wavelengths beyond 3.8 μm is achieved by reducing the losses in the TDFA stage and optimizing the ZBLAN fiber length. We demonstrate a novel (to our knowledge) approach of generating modulation instability-initiated SC starting from 1.55 μm by splitting the spectral shifting process into two steps. In the first step, amplified approximately nanosecond-long 1.55 μm laser diode pulses with ∼2.5 kW peak power generate a SC extending beyond 2.1 μm in ∼25 m length of standard single-mode fiber (SMF). The ∼2 μm wavelength components at the standard SMF output are amplified in a TDFA and coupled into ZBLAN fiber leading to mid-IR SC generation. Up to ∼270 nm SC long wavelength edge extension and ∼2.5× higher optical conversion efficiency to wavelengths beyond 3.8 μm are achieved by switching an Er:Yb-based power amplifier stage with a TDFA. The laser also demonstrates scalability in the average output power with respect to the pulse repetition rate and the amplifier pump power. Numerical simulations are performed by solving the generalized nonlinear Schrodinger equation, which show the long wavelength edge of the SC to be limited by the loss in ZBLAN.
TL;DR: A nanosecond-pulse erbium-doped fiber laser that is passively mode locked by a hollow-core photonic crystal fiber filled with few-layered graphene oxide solution is demonstrated, providing a simple and efficient approach to integrate the graphene into the optical fiber system.
Abstract: We demonstrate a nanosecond-pulse erbium-doped fiber laser that is passively mode locked by a hollow-core photonic crystal fiber filled with few-layered graphene oxide solution. Owing to the good solution processing capability of few-layered graphene oxide, which can be filled into the core of a hollow-core photonic crystal fiber through a selective hole filling process, a graphene saturable absorber can be successfully fabricated. The output pulses obtained have a center wavelength, pulse width, and repetition rate of 1561.2 nm, 4.85 ns, and 7.68 MHz, respectively. This method provides a simple and efficient approach to integrate the graphene into the optical fiber system.
TL;DR: Coherent beam combination of a 1.08 kW fiber amplifier array has been demonstrated for the first time and the fringe contrast of the far-field intensity pattern is improved to more than 85%, and the residual phase error is less than λ/15.
Abstract: Coherent beam combination of a 1.08 kW fiber amplifier array has been demonstrated for the first time, to our knowledge. In the experiment, nine fiber amplifiers are tiled into a 3×3 array, and the output power of each amplifier is approximately 120 W. A single frequency dithering algorithm is used to compensate the phase noises between the elements, which runs on a signal processor based on field programmable gate array for phase control on the fiber amplifiers. When the phase control system goes into closed loop, the fringe contrast of the far-field intensity pattern is improved to more than 85%, and the residual phase error is less than λ/15.
TL;DR: The pressure-assisted melt-filling approach makes it possible to realize highly nonlinear devices with unusual combinations of materials, and it is shown numerically that a 1 cm long As2S3:silica step-index fiber with a core diameter of 1 µm, pumped by 60 fs pulses at 1550 nm, would generate a broadband supercontinuum out to 4 µm.
Abstract: We explore the use of a highly nonlinear chalcogenide-silica waveguide for supercontinuum generation in the near infrared. The structure was fabricated by a pressure-assisted melt-filling of a silica capillary fiber (1.6 µm bore diameter) with Ga4Ge21Sb10S65 glass. It was designed to have zero group velocity dispersion (for HE11 core mode) at 1550 nm. Pumping a 1 cm length with 60 fs pulses from an erbium-doped fiber laser results in the generation of octave-spanning supercontinuum light for pulse energies of only 60 pJ. Good agreement is obtained between the experimental results and theoretical predictions based on numerical solutions of the generalized nonlinear Schrodinger equation. The pressure-assisted melt-filling approach makes it possible to realize highly nonlinear devices with unusual combinations of materials. For example, we show numerically that a 1 cm long As2S3:silica step-index fiber with a core diameter of 1 µm, pumped by 60 fs pulses at 1550 nm, would generate a broadband supercontinuum out to 4 µm.
TL;DR: An all-fiber-integrated laser based on off-the-shelf components producing square-shaped, 1 ns-long pulses at 1.03 μm wavelength with 3.1 MHz repetition rate and 83 W of average power is demonstrated.
Abstract: We demonstrate an all-fiber-integrated laser based on off-the-shelf components producing square-shaped, 1 ns-long pulses at 1.03 μm wavelength with 3.1 MHz repetition rate and 83 W of average power. The master-oscillator power-amplifier system is seeded by a fiber oscillator utilizing a nonlinear optical loop mirror and producing incompressible pulses. A simple technique is employed to demonstrate that the pulses indeed have a random chirp. We propose that the long pulse duration should result in more efficient material removal relative to picosecond pulses, while being short enough to minimize heat effects, relative to nanosecond pulses commonly used in micromachining. Micromachining of Ti surfaces using 0.1 ns, 1 ns and 100 ns pulses supports these expectations.
TL;DR: High-quality monolayer graphene as large as 1.2×1.2 cm2 was synthesized by chemical vapor deposition and used as a transmitting saturable absorber for efficient passive mode-locking of a femtosecond bulk solid-state laser.
Abstract: High-quality monolayer graphene as large as 1.2×1.2 cm2 was synthesized by chemical vapor deposition and used as a transmitting saturable absorber for efficient passive mode-locking of a femtosecond bulk solid-state laser. The monolayer graphene mode-locked Cr:forsterite laser was tunable around 1.25 μm and delivered sub-100 fs pulses with output powers up to 230 mW. The nonlinear optical characteristics of the monolayer graphene saturable absorber and the mode-locked operation were then compared with the case of the bilayer graphene saturable absorber.
TL;DR: Self-referencing of a Tm-doped fiber oscillator-amplifier system is demonstrated by performing octave-spanning supercontinuum generation in a periodically poled lithium niobate waveguide.
Abstract: We demonstrate self-referencing of a Tm-doped fiber oscillator–amplifier system by performing octave-spanning supercontinuum generation in a periodically poled lithium niobate waveguide. We model the supercontinuum generation numerically and show good agreement with the experiment.
TL;DR: A Raman fiber laser based on multiple point-action fiber Bragg grating reflectors and distributed feedback via Rayleigh scattering in an ~22-km-long optical fiber exhibits highly stable multiwavelength generation with a power-equalized uniform distribution, which is almost independent on power.
Abstract: We experimentally demonstrate a Raman fiber laser based on multiple point-action fiber Bragg grating reflectors and distributed feedback via Rayleigh scattering in an ∼22-km-long optical fiber. Twenty-two lasing lines with spacing of ∼100 GHz (close to International Telecommunication Union grid) in the C band are generated at the watt level. In contrast to the normal cavity with competition between laser lines, the random distributed feedback cavity exhibits highly stable multiwavelength generation with a power-equalized uniform distribution, which is almost independent on power. © 2011 Optical Society of America.
TL;DR: The first Si/III-V Fabry-Perot laser based on adiabatic mode transformers under quasi-continuous wave regime is reported, and the fiber-coupled output power is ∼7mW.
Abstract: We report the first demonstration of an electrically driven hybrid silicon/III-V laser based on adiabatic mode transformers. The hybrid structure is formed by two vertically superimposed waveguides separated by a 100-nm-thick SiO2 layer. The top waveguide, fabricated in an InP/InGaAsP-based heterostructure, serves to provide optical gain. The bottom Si-waveguides system, which supports all optical functions, is constituted by two tapered rib-waveguides (mode transformers), two distributed Bragg reflectors (DBRs) and a surface-grating coupler. The supermodes of this hybrid structure are controlled by an appropriate design of the tapers located at the edges of the gain region. In the middle part of the device almost all the field resides in the III-V waveguide so that the optical mode experiences maximal gain, while in regions near the III-V facets, mode transformers ensure an efficient transfer of the power flow towards Si-waveguides. The investigated device operates under quasi-continuous wave regime. The room temperature threshold current is 100 mA, the side-mode suppression ratio is as high as 20 dB, and the fiber-coupled output power is ~7 mW.
TL;DR: This work reports a first dissipative dispersive-managed soliton fiber laser operating at 2 μm, which employs chirped fiber Bragg grating and ensures net-normal cavity dispersion and semiconductor saturable absorber for mode-locking.
Abstract: We report a first dissipative dispersive-managed soliton fiber laser operating at 2 μm The cavity comprised of all-anomalous-dispersion fiber employs chirped fiber Bragg grating, which ensures net-normal cavity dispersion and semiconductor saturable absorber for mode-locking
TL;DR: By brushing and scribing an ultra-thin polymer polyvinyl alcohol (PVA) film on one end face of a FC/APC connector in erbium-doped fiber laser (EDFL), the intra-cavity graphite nano-particle based saturable absorber can be formed to induce passive mode-locking effect in the EDFL.
Abstract: By directly brushing and scribing an ultra-thin (< 5-μm thick) polymer polyvinyl alcohol (PVA) film on one end-face of a FC/APC connector in erbium-doped fiber laser (EDFL), and then imprinting it with the graphite nano-particles exfoliated from a graphite foil, the intra-cavity graphite nano-particle based saturable absorber can be formed to induce passive mode-locking effect in the EDFL. Such a novel approach greatly suppresses the film-thickness induced laser-beam divergent loss to 3.4%, thus enhancing the intra-cavity circulating power to promote the shortening on mode-locking pulsewidth. The saturable absorber with area coverage ratio of graphite nano-particles is detuned from 70 to 25% to provide the modulation depth enhancing from 11 to 20% and the saturated transmittance from 27 to 60%. Optimizing the coverage ratio reduces the non-saturable loss to 40% and enhances the modulation depth to 21%, such that the sub-ps soliton mode-locking can be initiated to provide a chirped pulsewidth of 482 fs and a linewidth of 2.87 nm.
TL;DR: A diode-pumped, actively Q-switched 2.8 μm fiber laser oscillator with an average output power of more than 12 W has been realized through the use of a 35 μm core erbium-doped ZBLAN fiber and an acousto-optic modulator; to the authors' knowledge, this is the first 3 μm pulsed fiber laser in the 10 W class.
Abstract: A diode-pumped, actively Q-switched 2.8 μm fiber laser oscillator with an average output power of more than 12 W has been realized through the use of a 35 μm core erbium-doped ZBLAN fiber and an acousto-optic modulator; to our knowledge, this is the first 3 μm pulsed fiber laser in the 10 W class. Pulse energy up to 100 μJ and pulse duration down to 90 ns, corresponding to a peak power of 0.9 kW, were achieved at a repetition rate of 120 kHz.
TL;DR: A simplified dual-comb LIDAR setup for precision absolute ranging that can achieve a ranging precision of 2 μm in 140 μs acquisition time and provides a factor of three improved performance over the previous coherent dual comb LIDar system.
Abstract: We demonstrate a simplified dual-comb LIDAR setup for precision absolute ranging that can achieve a ranging precision of 2 μm in 140 μs acquisition time. With averaging, the precision drops below 1 μm at 0.8 ms and below 200 nm at 20 ms. The system can measure the distance to multiple targets with negligible dead zones and a ranging ambiguity of 1 meter. The system is much simpler than a previous coherent dual-comb LIDAR because the two combs are replaced by free-running, saturable-absorber-based femtosecond Er fiber lasers, rather than tightly phase-locked combs, with the entire time base provided by a single 10-digit frequency counter. Despite the simpler design, the system provides a factor of three improved performance over the previous coherent dual comb LIDAR system.