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Kelleher EJR, Travers JC, Ippen EP, Sun Z, Ferrari AC, Popov SV, Taylor JR. Generation and direct measurement of giant chirp in a passively mode-locked laser. Opt Lett 2009; 34:3526-3528. [PMID: 19927199 DOI: 10.1364/ol.34.003526] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We evaluate the shape and chirp of nanosecond pulses from a fiber laser passively mode locked with a nanotube-based saturable absorber by using a synchronously scanning streak camera and a monochromator to directly measure the pulse spectrogram. We show that the stable sech(2) output pulse possesses a predominantly linear chirp, with a residual quartic phase and low noise. Comparison with analytical mode-locking theory shows a good quantitative agreement with the master equation mode-locking model.
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Affiliation(s)
- E J R Kelleher
- Femtosecond Optics Group, Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, UK.
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2
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Spector SJ, Geis MW, Zhou GR, Grein ME, Gan F, Popovic MA, Yoon JU, Lennon DM, Ippen EP, Kärtner FZ, Lyszczarz TM. CMOS-compatible dual-output silicon modulator for analog signal processing. Opt Express 2008; 16:11027-11031. [PMID: 18648416 DOI: 10.1364/oe.16.011027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2008] [Accepted: 07/24/2008] [Indexed: 05/26/2023]
Abstract
A broadband, Mach-Zehnder-interferometer based silicon optical modulator is demonstrated, with an electrical bandwidth of 26 GHz and V(pi)L of 4 V.cm. The design of this modulator does not require epitaxial overgrowth and is therefore simpler to fabricate than previous devices with similar performance.
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Affiliation(s)
- S J Spector
- Lincoln Laboratory, Massachusetts Institute of Technology, Lexington, MA 02420, USA.
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3
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Barwicz T, Byun H, Gan F, Holzwarth CW, Popovic MA, Rakich PT, Watts MR, Ippen EP, Kärtner FX, Smith HI, Orcutt JS, Ram RJ, Stojanovic V, Olubuyide OO, Hoyt JL, Spector S, Geis M, Grein M, Lyszczarz T, Yoon JU. Silicon photonics for compact, energy-efficient interconnects [Invited]. ACTA ACUST UNITED AC 2007. [DOI: 10.1364/jon.6.000063] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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4
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Grawert FJ, Ilday EO, Kielpinski DF, Gopinath JT, Petrich GS, Kolodziejski LA, Ippen EP, Kärtner FX. Automatic feedback control of an Er-doped fiber laser with an intracavity loss modulator. Opt Lett 2005; 30:1066-8. [PMID: 15907005 DOI: 10.1364/ol.30.001066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Suppression of Q-switching instabilities with an actively controlled intracavity loss modulator is demonstrated in an Er-doped waveguide laser that is mode locked with a slow saturable absorber at repetition rates of as much as 100 MHz. By automatic gain control in the feedback loop, stable mode locking is achieved over the entire parameter range of the laser. This approach renders laser stabilization independent of the characteristics of the gain medium and intracavity power. The pulse-shaping dynamics is not affected by the presence of the intracavity loss modulator.
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Affiliation(s)
- F J Grawert
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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5
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Abstract
A mode-evolution-based polarization splitter suitable for high-index-contrast systems and directly integratable with a recently reported on-polarization rotator is described and its performance verified through both finite-difference time-domain and eigenmode expansion simulations. For a device length of 200 microm, greater than 22 dB of extinction is obtained across a 1.45-1.75-microm bandwidth.
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Affiliation(s)
- M R Watts
- Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
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6
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Kowalevicz AM, Sharma V, Ippen EP, Fujimoto JG, Minoshima K. Three-dimensional photonic devices fabricated in glass by use of a femtosecond laser oscillator. Opt Lett 2005; 30:1060-2. [PMID: 15907003 DOI: 10.1364/ol.30.001060] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Three-dimensional photonic waveguide devices are fabricated in glass by use of femtosecond pulses from an extended-cavity laser oscillator. Three-dimensional devices, including a symmetric three-waveguide directional coupler and a three-dimensional microring resonator, are fabricated and tested. Waveguides can be fabricated at depths of approximately 1 mm inside a glass substrate, thus demonstrating the capability of achieving dramatic increases in device density. These results demonstrate the potential to fabricate new classes of devices that are not possible in two dimensions.
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Affiliation(s)
- A M Kowalevicz
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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7
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Grawert FJ, Gopinath JT, Ilday FO, Shen HM, Ippen EP, Kärtner FX, Akiyama S, Liu J, Wada K, Kimerling LC. 220-fs erbium-ytterbium:glass laser mode locked by a broadband low-loss silicon/germanium saturable absorber. Opt Lett 2005; 30:329-331. [PMID: 15751901 DOI: 10.1364/ol.30.000329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We demonstrate femtosecond performance of an ultrabroadband high-index-contrast saturable Bragg reflector consisting of a silicon/silicon dioxide/germanium structure that is fully compatible with CMOS processing. This device offers a reflectivity bandwidth of over 700 nm and subpicosecond recovery time of the saturable loss. It is used to achieve mode locking of an Er-Yb:glass laser centered at 1540 nm, generating 220-fs pulses, with what is to our knowledge the broadest output spectrum to date.
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Affiliation(s)
- F J Grawert
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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8
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Nishizawa N, Chen Y, Hsiung P, Ippen EP, Fujimoto JG. Real-time, ultrahigh-resolution, optical coherence tomography with an all-fiber, femtosecond fiber laser continuum at 1.5 microm. Opt Lett 2004; 29:2846-8. [PMID: 15645800 DOI: 10.1364/ol.29.002846] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Real-time, ultrahigh-resolution optical coherence tomography (OCT) is demonstrated in the 1.4-1.7-microm wavelength region with a stretched-pulse, passively mode-locked, Er-doped fiber laser and highly nonlinear fiber. The fiber laser generates 100-mW, linearly chirped pulses at a 51-MHz repetition rate. The pulses are compressed and then coupled into a normally dispersive highly nonlinear fiber to generate a low-noise supercontinuum with a 180-nm FWHM bandwidth and 38 mW of output power. This light source is stable, compact, and broadband, permitting high-speed, real-time, high-resolution OCT imaging. In vivo high-speed OCT imaging of human skin with approximately 5.5-microm resolution and 99-dB sensitivity is demonstrated.
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Affiliation(s)
- N Nishizawa
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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9
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Mücke OD, Kuzucu O, Wong FNC, Ippen EP, Kärtner FX, Foreman SM, Jones DJ, Ma LS, Hall JL, Ye J. Experimental implementation of optical clockwork without carrier-envelope phase control. Opt Lett 2004; 29:2806-2808. [PMID: 15605512 DOI: 10.1364/ol.29.002806] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We demonstrate optical clockwork without the need for carrier-envelope phase control by use of sum-frequency generation between a continuous-wave optical parametric oscillator at 3.39 microm and a femtosecond mode-locked Ti:sapphire laser with two strong spectral peaks at 834 and 670 nm, a spectral difference matched by the 3.39-microm radiation.
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Affiliation(s)
- O D Mücke
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307, USA.
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10
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Tandon SN, Gopinath JT, Shen HM, Petrich GS, Kolodziejski LA, Kärtner FX, Ippen EP. Large-area broadband saturable Bragg reflectors by use of oxidized AlAs. Opt Lett 2004; 29:2551-2553. [PMID: 15584291 DOI: 10.1364/ol.29.002551] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Broadband saturable Bragg reflectors (SBRs) are designed and fabricated by monolithic integration of semiconductor saturable absorbers with broadband Bragg mirrors. The wet oxidation of AlAs creates low-index AlxOy layers for broadband, high-index-contrast AlGaAs/AlxOy or InGaAlP/AlxOy mirrors. SBR mirror designs indicate greater than 99% reflectivity over bandwidths of 294, 466, and 563 nm for center wavelengths of 800, 1300, and 1550 nm, respectively. Highly strained and unstrained absorbers are stably integrated with the oxidized mirrors. Large-scale lateral oxidation techniques permit the fabrication of SBRs with diameters of 500 microm. Large-area, broadband SBRs are used to self-start and mode lock a variety of laser systems at wavelengths from 800 to 1550 nm.
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Affiliation(s)
- S N Tandon
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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11
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Matos L, Kleppner D, Kuzucu O, Schibli TR, Kim J, Ippen EP, Kaertner FX. Direct frequency comb generation from an octave-spanning, prismless Ti:sapphire laser. Opt Lett 2004; 29:1683-1685. [PMID: 15309859 DOI: 10.1364/ol.29.001683] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We describe a self-referenced optical frequency comb generator based on an octave-spanning, prismless Ti:sapphire laser. Dispersion compensation is provided by novel double-chirped mirror pairs and BaF2 wedges. Current versions operate at 80 and 150 MHz. The compact prismless design allows system scaling to a gigahertz repetition rate. Its carrier-envelope beat note is intrinsically stable with a signal-to-noise ratio of 30 dB in a 100-kHz bandwidth. The octave is reached at 25 dB below the average power level. The in-loop accumulated phase error is 1.4 rad (20 mHz to 1 MHz). The technique has the advantages of simplicity and stability compared with previous designs.
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Affiliation(s)
- L Matos
- Department of Physics and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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12
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Schibli TR, Kim J, Kuzucu O, Gopinath JT, Tandon SN, Petrich GS, Kolodziejski LA, Fujimoto JG, Ippen EP, Kaertner FX. Attosecond active synchronization of passively mode-locked lasers by balanced cross correlation. Opt Lett 2003; 28:947-949. [PMID: 12816255 DOI: 10.1364/ol.28.000947] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A balanced cross correlator, the optical equivalent of a balanced microwave phase detector, is demonstrated. Its use in synchronizing an octave-spanning Ti:sapphire laser and a 30-fs Cr:forsterite laser yields 300-attosecond timing jitter measured from 10 mHz to 2.3 MHz. The spectral overlap between the two lasers is strong enough to permit direct detection of the difference in carrier-envelope offset frequency between the two lasers.
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Affiliation(s)
- T R Schibli
- Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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13
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Grein ME, Jiang LA, Haus HA, Ippen EP, McNeilage C, Searls JH, Windeler RS. Observation of quantum-limited timing jitter in an active, harmonically mode-locked fiber laser. Opt Lett 2002; 27:957-959. [PMID: 18026336 DOI: 10.1364/ol.27.000957] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report on the observation of quantum-limited timing jitter in a harmonically mode-locked soliton fiber laser with an ultralow-noise local oscillator. The effects of amplitude and phase modulation on the spectrum are described and compared with theory.
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14
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Ripin DJ, Chudoba C, Gopinath JT, Fujimoto JG, Ippen EP, Morgner U, Kärtner FX, Scheuer V, Angelow G, Tschudi T. Generation of 20-fs pulses by a prismless Cr(4+):YAG laser. Opt Lett 2002; 27:61-63. [PMID: 18007716 DOI: 10.1364/ol.27.000061] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Ultrafast optical pulses shorter than 20 fs with 400-mW average power at a 110-MHz repetition rate have been generated by a Cr(4+):YAG laser with only double-chirped mirrors for dispersion compensation. The corresponding pulse spectrum has a peak intensity at 1450 nm and extends from 1310 to 1500 nm full width at half-maximum (FWHM). These pulses, which are believed to be the shortest generated to date from a Cr(4+):YAG laser, are only four optical cycles within the FWHM intensity width.
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15
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Abstract
It is shown that, in addition to the well-known phase accumulation of a traveling soliton, which may be interpreted as a change of phase velocity as a result of the Kerr nonlinearity, there is a change in the speed of travel of the envelope, the group velocity. This analysis is extended to dispersion-managed solitons, for which it is shown that the discrepancy between phase- and group-velocity changes is generally smaller.
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16
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Minoshima K, Kowalevicz AM, Hartl I, Ippen EP, Fujimoto JG. Photonic device fabrication in glass by use of nonlinear materials processing with a femtosecond laser oscillator. Opt Lett 2001; 26:1516-1518. [PMID: 18049653 DOI: 10.1364/ol.26.001516] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Single-mode X couplers and three-dimensional waveguides are fabricated in transparent glasses by use of an unamplified femtosecond laser generating energies of up to 100 nJ. Changing fabrication parameters such as power and scanning speed permits creation of waveguides with a wide range of structures and refractive-index difference. Optical coherence tomography shows large refractive-index changes of up to ~10(-2) in the waveguides; these changes are consistent with guided mode analysis.
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17
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Morgner U, Ell R, Metzler G, Schibli TR, Kärtner FX, Fujimoto JG, Haus HA, Ippen EP. Nonlinear optics with phase-controlled pulses in the sub-two-cycle regime. Phys Rev Lett 2001; 86:5462-5465. [PMID: 11415276 DOI: 10.1103/physrevlett.86.5462] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2000] [Indexed: 05/23/2023]
Abstract
Nonlinear optical effects due to the phase between carrier and envelope are observed with 5 fs pulses from a Kerr-lens mode-locked Ti:sapphire laser. These sub-two-cycle pulses with octave spanning spectra are the shortest pulses ever generated directly from a laser oscillator. Detection of the carrier-envelope phase slip is made possible by simply focusing the short pulses directly from the oscillator into a BBO crystal. As a further example of nonlinear optics with such short pulses, the interference between second- and third-harmonic components is also demonstrated.
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Affiliation(s)
- U Morgner
- High Frequency and Quantum Electronics Laboratory, University of Karlsruhe, Engesserstrasse 5, D-76128 Karlsruhe, Germany
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18
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Abstract
We demonstrate what is to our knowledge the first all-fiber squeezing experiment. A balanced Sagnac loop is used, and a record 6.1+/-0.2dB of noise reduction below shot noise has been obtained without stabilization. A gigahertz Er-doped fiber laser and a high-power double-clad Er-Yb amplifier have been developed to suppress guided acoustic-wave Brillouin scattering and to make possible the all-fiber configuration.
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19
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Cho SH, Kärtner FX, Morgner U, Ippen EP, Fujimoto JG, Cunningham JE, Knox WH. Generation of 90-nJ pulses with a 4-MHz repetition-rate Kerr-lens mode-locked Ti:Al(2)O(3) laser operating with net positive and negative intracavity dispersion. Opt Lett 2001; 26:560-562. [PMID: 18040385 DOI: 10.1364/ol.26.000560] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We demonstrate the generation of high-energy pulses by using a low-repetition-rate Kerr-lens mode-locked laser. Repetition rates as low as 4 MHz were achieved with a long, multiple-pass cavity and a semiconductor saturable Bragg reflector. The laser generated pulses of 55-fs duration with a pulse energy of 48 nJ when it was mode locked in the net negative dispersion regime. Mode locking in the positive dispersion regime reduces instabilities and enables pulses to have durations of 80 fs and energies as high as 90 nJ. This is, to our knowledge, the highest pulse energy and the lowest repetition rate ever generated directly from a femtosecond laser resonator without cavity dumping.
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20
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Ell R, Morgner U, Kãârtner FX, Fujimoto JG, Ippen EP, Scheuer V, Angelow G, Tschudi T, Lederer MJ, Boiko A, Luther-Davies B. Generation of 5-fs pulses and octave-spanning spectra directly from a Ti:sapphire laser. Opt Lett 2001; 26:373-375. [PMID: 18040328 DOI: 10.1364/ol.26.000373] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Spectra extending from 600 to 1200 nm have been generated from a Kerr-lens mode-locked Ti:sapphire laser producing 5-fs pulses. Specially designed double-chirped mirror pairs provide broadband controlled dispersion, and a second intracavity focus in a glass plate provides additional spectral broadening. These spectra are to our knowledge the broadest ever generated directly from a laser oscillator.
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21
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Chudoba C, Fujimoto JG, Ippen EP, Haus HA, Morgner U, Kärtner FX, Scheuer V, Angelow G, Tschudi T. All-solid-state Cr:forsterite laser generating 14-fs pulses at 1.3 mum. Opt Lett 2001; 26:292-294. [PMID: 18040305 DOI: 10.1364/ol.26.000292] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report the generation of 14-fs pulses at 1.3mum with 80-mW average power at 100-MHz repetition rate by an all-solid-state Kerr-lens mode-locked Cr:forsterite laser. The laser spectrum covers wavelengths of 1230-1580 nm, with a FWHM of 250 nm. Since 1.3-mum wavelengths are close to the zero dispersion wavelength of Cr:forsterite, higher-order dispersion is the main factor limiting pulse durations. We use specially designed and fabricated double-chirped mirrors in combination with high-index PBH71 prisms to compensate for the intracavity dispersion over almost 300 nm.
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22
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Yu CX, Haus HA, Ippen EP, Wong WS, Sysoliatin A. Gigahertz-repetition-rate mode-locked fiber laser for continuum generation. Opt Lett 2000; 25:1418-1420. [PMID: 18066234 DOI: 10.1364/ol.25.001418] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report direct generation of <500-fs pulses at a 1-GHz rate from a self-starting passively mode-locked fiber laser by regeneratively synchronizing the pulses with a phase modulator. The pulses are amplified and passed through a dispersion-decreasing fiber and a normal-dispersion supercontinuum fiber. The resulting continuum is wider than 350 nm.
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23
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Thoen ER, Grein ME, Koontz EM, Ippen EP, Haus HA, Kolodziejski LA. Stabilization of an active harmonically mode-locked fiber laser using two-photon absorption. Opt Lett 2000; 25:948-950. [PMID: 18064236 DOI: 10.1364/ol.25.000948] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Two-photon absorption provided by a semiconductor mirror structure is shown to reduce amplitude fluctuations significantly in a harmonically mo e-locked fiber ring laser. Pulse dropouts are eliminated in a laser that produces picosecond pulses at a repetition rate of 2 GHz.
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24
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Morgner U, Drexler W, Kärtner FX, Li XD, Pitris C, Ippen EP, Fujimoto JG. Spectroscopic optical coherence tomography. Opt Lett 2000; 25:111-3. [PMID: 18059799 DOI: 10.1364/ol.25.000111] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Spectroscopic optical coherence tomography (OCT), an extension of conventional OCT, is demonstrated for performing cross-sectional tomographic and spectroscopic imaging. Information on the spectral content of backscattered light is obtained by detection and processing of the interferometric OCT signal. This method allows the spectrum of backscattered light to be measured over the entire available optical bandwidth simultaneously in a single measurement. Specific spectral features can be extracted by use of digital signal processing without changing the measurement apparatus. An ultrabroadband femtosecond Ti:Al(2)O(3) laser was used to achieve spectroscopic imaging over the wavelength range from 650 to 1000 nm in a simple model as well as in vivo in the Xenopus laevis (African frog) tadpole. Multidimensional spectroscopic data are displayed by use of a novel hue-saturation false-color mapping.
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25
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Langlois P, Ippen EP. Measurement of pulse asymmetry by three-photon-absorption autocorrelation in a GaAsP photodiode. Opt Lett 1999; 24:1868-70. [PMID: 18079958 DOI: 10.1364/ol.24.001868] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Three-photon absorption in a GaAsP photodiode is used for what is believed to be the first time for nonlinear optical autocorrelation at wavelengths from 1.4 to 1.6microm . Theoretical intensity dependence and contrast ratios are achieved, and the ratio of the three- to the two-photon-absorption coefficient is measured. Finally, it is demonstrated that pulse asymmetry can be measured with no direction-of-time ambiguity by use of unbalanced three-photon-absorption autocorrelation.
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26
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Grein ME, Jiang LA, Chen Y, Haus HA, Ippen EP. Timing restoration dynamics in an actively mode-locked fiber ring laser. Opt Lett 1999; 24:1687-1689. [PMID: 18079903 DOI: 10.1364/ol.24.001687] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Using electronic phase detection, we study the dynamics that govern pulse retiming in an actively mode-locked fiber laser. We compare the dynamics for amplitude and for phase modulation and identify the characteristic time constants for each case. The retiming dynamics for amplitude modulation are revealed as a first-order exponential decay, whereas for phase modulation the dynamics are those of a damped harmonic oscillator. We show that the measured time constants agree with predictions given by the soliton perturbation theory.
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27
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Drexler W, Morgner U, Kärtner FX, Pitris C, Boppart SA, Li XD, Ippen EP, Fujimoto JG. In vivo ultrahigh-resolution optical coherence tomography. Opt Lett 1999; 24:1221-3. [PMID: 18073990 DOI: 10.1364/ol.24.001221] [Citation(s) in RCA: 214] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Ultrahigh-resolution optical coherence tomography (OCT) by use of state of the art broad-bandwidth femtosecond laser technology is demonstrated and applied to in vivo subcellular imaging. Imaging is performed with a Kerr-lens mode-locked Ti:sapphire laser with double-chirped mirrors that emits sub-two-cycle pulses with bandwidths of up to 350 nm, centered at 800 nm. Longitudinal resolutions of ~1mum and transverse resolution of 3mum, with a 110-dB dynamic range, are achieved in biological tissue. To overcome depth-of-field limitations we perform zone focusing and image fusion to construct a tomogram with high transverse resolution throughout the image depth. To our knowledge this is the highest longitudinal resolution demonstrated to date for in vivo OCT imaging.
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28
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Morgner U, Kärtner FX, Cho SH, Chen Y, Haus HA, Fujimoto JG, Ippen EP, Scheuer V, Angelow G, Tschudi T. Sub-two-cycle pulses from a Kerr-lens mode-locked Ti:sapphire laser: addenda. Opt Lett 1999; 24:920. [PMID: 18073896 DOI: 10.1364/ol.24.000920] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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Cho SH, Bouma BE, Ippen EP, Fujimoto JG. Low-repetition-rate high-peak-power Kerr-lens mode-locked TiAl(2)O(3) laser with a multiple-pass cavity. Opt Lett 1999; 24:417-419. [PMID: 18071525 DOI: 10.1364/ol.24.000417] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We demonstrate a novel, long, multiple-pass cavity (MPC) to obtain low repetition rates and high peak intensities from Kerr-lens mode-locked lasers. We show that the MPC provides a zero effective length by a unity transformation of the q parameter after a given number of transits of the laser beam. Pulse durations of 16.5 fs with 0.7 MW of power at a 15-MHz repetition rate are achieved. This is, to our knowledge, the lowest repetition rate ever achieved directly from a femtosecond laser resonator without use of additional active devices and cavity dumping. The combination of low repetition rates and high peak intensity is extremely useful for femtosecond pump-probe and other nonlinear experiments because it permits the application of high peak intensity without excessive average power.
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30
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Morgner U, Kärtner FX, Cho SH, Chen Y, Haus HA, Fujimoto JG, Ippen EP, Scheuer V, Angelow G, Tschudi T. Sub-two-cycle pulses from a Kerr-lens mode-locked Ti:sapphire laser. Opt Lett 1999; 24:411-413. [PMID: 18071523 DOI: 10.1364/ol.24.000411] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Pulses shorter than two optical cycles with bandwidths in excess of 400 nm have been generated from a Kerr-lens mode-locked Ti:sapphire laser with a repetition rate of 90 MHz and an average power of 200 mW. Low-dispersion prisms and double-chirped mirrors provide broadband controlled dispersion and high reflectivity. These pulse durations are to our knowledge the shortest ever generated directly from a laser oscillator.
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31
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Abstract
Resonant sideband production in stretched-pulse fiber lasers operating with net normal dispersion is investigated. A theoretical formulation is compared with numerical modeling and experimental results. The inherent difference from sideband generation in soliton lasers is discussed. We also consider the implications of sideband formation in related dispersion-managed soliton transmission systems.
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Affiliation(s)
- D J Jones
- Department of Electrical Engineering and Computer Science and Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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32
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Abstract
We investigate the dynamics of a 5-Gbit/s packet of ones and zeros loaded into a 0.5-kbit, phase-modulated optical fiber-ring buffer. A new mode of operation is explored in which the cavity length of the buffer is slightly detuned from the frequency driving the phase modulator. We examine the conditions for successful packet loading and the packet storage behavior. In addition, relaxation oscillations, which affected the storage time of previous high-speed optical ring buffers, are nearly eliminated with a cw holding beam, and significantly enhanced storage times are obtained.
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33
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Abstract
We directly measure the time-independent nonlinear self-phase shift of a pulse after fiber propagation by spectral interferometry. Both the soliton and the nonsoliton case were studied. We verify numerically that the measured phase shift approximates this time-independent phase well.
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34
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Wong WS, Namiki S, Margalit M, Haus HA, Ippen EP. Self-switching of optical pulses in dispersion-imbalanced nonlinear loop mirrors. Opt Lett 1997; 22:1150-1152. [PMID: 18185778 DOI: 10.1364/ol.22.001150] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We report a novel nonlinear filter that transmits and shortens incident pulses while rejecting cw background as well as resonant continuum. A relative extinction of 22dB is reported for the cw background.
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35
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Jones DJ, Haus HA, Ippen EP. Subpicosecond solitons in an actively mode-locked fiber laser. Opt Lett 1996; 21:1818-1820. [PMID: 19881812 DOI: 10.1364/ol.21.001818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Experimental results are presented for a study of the stability regime of an actively mode-locked polarizationmaintaining fiber ring laser used as a memory. Observations indicate that the pulse widths in the memory can be reduced (by soliton effects) by a factor of approximately 4.4 below the pulse widths predicted by standard active mode-locking theory. Stability regions for the solitons are mapped and compared with theoretical predictions.
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36
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Abstract
We report optimization of a stretched-pulse erbium-doped fiber laser for second-harmonic generation and the evaluation of several nonlinear crystals for this application. With compressed fundamental pulse energies of 2.7 nJ at 31.8 MHz, we achieved 10% conversion efficiency and 86-fs, 771-nm pulses with energies of 270 pJ. Frequency-resolved optical gating was used to analyze both the fundamental and the frequencydoubled pulses.
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37
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Zeiger HJ, Cheng TK, Ippen EP, Vidal J, Dresselhaus G, Dresselhaus MS. Femtosecond studies of the phase transition in Ti2O3. Phys Rev B Condens Matter 1996; 54:105-123. [PMID: 9984236 DOI: 10.1103/physrevb.54.105] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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38
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Abstract
Examination of the output beam size from a 10-fs Kerr-lens mode-locked Ti:sapphire laser reveals a strong spectral dependence. These results provide insight into the details of the mode-locking mechanisms and suggest reasons for the current limitations on the shortest achievable pulses.
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39
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Lenz G, Gellermann W, Dougherty DJ, Tamura K, Ippen EP. Femtosecond fiber laser pulses amplified by a KCl:Tl+ color-center amplifier for continuum generation in the 1.5-microm region. Opt Lett 1996; 21:137-139. [PMID: 19865330 DOI: 10.1364/ol.21.000137] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A diode-pumped stretched-pulse additive-pulse mode-locked Er-doped fiber laser is used to seed a KCl:Tl + color-center amplif ier crystal. The initial l-nJ chirped pulses are double passed through the amplif ier, which is pumped by a 1-kHz Q-switched Nd:YAG laser. The resulting 10-microJ pulses are then chirp compensated to 250-fs duration and are used to generate a spectral continuum. A few high-n(2) materials are investigated for continuum generation, and spectral slicing of the continuum is demonstrated.
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40
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Abstract
We report on a stretched-pulse additive-pulse mode-locked erbium-doped fiber laser pumped by a masteroscillator/power-amplifier diode at 980 nm. This laser operates at 1.55 microm and puts out as much as 90 mW of average power at 40 MHz with pulse widths that are prism compensated to less than 90 fs. Amplitude jitter is less than 0.1%.
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41
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Abstract
The stimulated Raman gain spectrum of optical fibers has been measured down to 6 cm(-1) by means of short pulses. Results for parallel and perpendicular polarizations are reported. With this technique, we observe spectral oscillations arising from a Brillouin mediated coupling between cw and pulsed light.
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42
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Abstract
We report a harmonically mode-locked erbium-doped fiber ring laser with short solitons. A phase modulator running asynchronously with the pulses provides pulse start-up, continuous background cleanup, and a new form of pulse timing stabilization. Steady-state operation of picosecond solitons at a repetition rate of 1 GHz was obtained with no need for modulator drive frequency stabilization.
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43
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Doerr CR, Tamura K, Shirasaki M, Haus HA, Ippen EP. Orthogonal polarization fiber gyroscope with increased stability and resolution. Appl Opt 1994; 33:8062-8068. [PMID: 20963026 DOI: 10.1364/ao.33.008062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The orthogonal polarization fiber gyroscope (OPFG) is an interferometric fiber gyroscope design that requires no phase bias in the fiber ring and is insensitive to light-source intensity noise. However, in the original OPFG [Hitachi Rev. 33, 215 (1984)], environmental changes caused first-order false rotation signals. We propose and experimentally verify modifications that eliminate the first-order sensitivity to environmental changes and that improve the gyroscope's resolution as well. We believe that this modified OPFG is the first interferometric fiber gyroscope capable of stable, high-sensitivity measurement that contains only reciprocal optical elements.
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44
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Sun C, Vallée F, Acioli LH, Ippen EP, Fujimoto JG. Femtosecond-tunable measurement of electron thermalization in gold. Phys Rev B Condens Matter 1994; 50:15337-15348. [PMID: 9975886 DOI: 10.1103/physrevb.50.15337] [Citation(s) in RCA: 211] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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45
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Abstract
A pulse-storage ring is an optical device capable of memorizing a pulse sequence of 0's and l's. The soliton ring of Nakazawa et al. [Electron. Lett. 29, 729 (1993)] with nearly unlimited transmission distance is such a device. We propose and experimentally demonstrate a different type of pulse-storage ring that uses intensity-dependent interferometric action to create a stronger intracavity transmission differential between the 0's and the l's.
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46
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Abstract
We report 5.1 dB of squeezing from a fiber interferometer pumped with a 1-GHz pulse source that successfully eliminates guided-acoustic-wave Brillouin scattering in significant frequency regimes. The pulse source is a diode-pumped Nd:YLF laser actively mode locked at 1.314 microm. The squeezing results are consistent with the limits imposed by the Gaussian pulse shape and the detection quantum efficiency.
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47
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Abstract
When lasers with a long gain-relaxation time are actively mode locked at a harmonic of the round-trip frequency, the energy fluctuates from pulse to pulse unless stabilized. We report a new principle for pulse energy stabilization in harmonically mode-locked lasers.
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48
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Tamura K, Doerr CR, Nelson LE, Haus HA, Ippen EP. Technique for obtaining high-energy ultrashort pulses from an additive-pulse mode-locked erbium-doped fiber ring laser. Opt Lett 1994; 19:46-48. [PMID: 19829538 DOI: 10.1364/ol.19.000046] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report a self-starting stretched-pulse polarization additive-pulse mode-locked erbium-doped fiber ring laser with high output power. By using the light normally absorbed by the intracavity polarizer as the output, we obtained pulses with energies greater than 0.5 nJ at a repetition rate of 48 MHz. External chirp compensation was used to shorten the highly chirped output pulses to durations of less than 100 fs. The power levels suggest that erbium-doped fiber lasers may replace bulk solid-state lasers, such as the color-center laser, for some applications.
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49
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Paye J, Ramaswamy M, Fujimoto JG, Ippen EP. Measurement of the amplitude and phase of ultrashort light pulses from spectrally resolved autocorrelation. Opt Lett 1993; 18:1946-1948. [PMID: 19829456 DOI: 10.1364/ol.18.001946] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A new technique for determining the complex electric field of an ultrashort light pulse is analyzed and experimentally demonstrated. It is based on the measurement of the spectrally resolved intensity autocorrelation and an iterative procedure of data deconvolution. This method is shown to be convenient and reliable.
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50
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Sun C, Vallée F, Acioli L, Ippen EP, Fujimoto JG. Femtosecond investigation of electron thermalization in gold. Phys Rev B Condens Matter 1993; 48:12365-12368. [PMID: 10007603 DOI: 10.1103/physrevb.48.12365] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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