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ABSTRACT: Power performance of a continuous-wave Cr<sup>2+</sup>:ZnSe laser
was investigated experimentally and numerically at 2.47 μm. In the
experiments, an astigmatically compensated z-cavity with a 3%
transmitting output coupler produced as high as 250 mW of output power
when excited by a NaCl:OH<sup>$</sup>color-center laser at 1.58 μm.
The measured absorbed power slope efficiency was 24.2%. Experimental
pump absorption saturation and laser efficiency data were analyzed by
using a numerical model to determine the absorption, emission, and
excited-state absorption cross-sections. Simulations were then performed
to investigate the dependence of the output power on crystal and
resonator parameters. Results indicate that optimum power performance
should be obtained with a 1.5-cm-long crystal which has a total
unsaturated absorption of 86%. Finally, the optimum output coupling of
the resonator was determined to be 10%
IEEE Journal of Quantum Electronics 11/2000; · 1.88 Impact Factor
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ABSTRACT: We present and analyze an experimental bifurcation diagram for the additive-pulse modelocked (APM) laser, reconfirming the existence of both quasiperiodicity and period-doubling bifurcations into chaos for this system. Large fiber coupling is required to observe period doublings into chaos, while quasiperiodicity occurs for small fiber coupling. The experimental chaotic time series are reconstructed in phase space using the method of delayed coordinates, then graphically compared with the expected orbits from APM simulations. This experimental bifurcation diagram for the APM laser demonstrates that the main contribution to APM instability is in fact deterministic. © 2000 American Institute of Physics.
Applied Physics Letters 09/2000; 77(12):1771-1773. · 3.84 Impact Factor
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ABSTRACT: We describe active mode locking of a Cr(2+):ZnSe laser operating near 2.5 mum. The laser produces 4.4-ps transform-limited Gaussian-shaped pulses and produces 82 mW of average power.
Optics Letters 03/2000; 25(3):168-70. · 3.40 Impact Factor
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ABSTRACT: Advanced research in miniaturizing components for fiber-optic communication systems is required to extend optical fiber from trunk line to the subscriber's end. WDM offers high capacity but requires the fabrication of selective add-drop filters. MEMS technology offers an effective way to fabricate these components at low cost. We present a micromachined tunable filter on chip, integrated with an optical fiber. We demonstrate that the reflected (drop-out) wavelength can be tuned by varying the coupling between the fiber grating and a movable silicon block
Optical MEMS, 2000 IEEE/LEOS International Conference on; 02/2000
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ABSTRACT: The authors present the design and modelocking results of a
self-starting additive-pulse modelocked (APM) NaCl:OH-laser, using a
novel saturable Bragg reflector (SBR) as the starting mechanism. This
new SBR/APM laser produces ~200 fs pulses without dedicated dispersion
compensating optics, and maintains a stable pulse train even without
active cavity length stabilisation
Electronics Letters 08/1998; · 0.96 Impact Factor
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ABSTRACT: We have studied the dynamics of the additive-pulse modelocked (APM) laser under several parameter variations, such as fiber length, fiber coupling strength, and small-signal gain. We simulated and characterized these dynamics, which exhibit both quasiperiodic and chaotic behavior
Lasers and Electro-Optics Society Annual Meeting, 1997. LEOS '97 10th Annual Meeting. Conference Proceedings., IEEE; 12/1997
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ABSTRACT: Optical amplification is demonstrated in waveguides of composite materials consisting of nanocrystals of Cr:forsterite or Cr:diopside embedded in a host polymer with a matching refractive index. Small-signal gains of 1dB / cm at lambda=1.23microm are reported.
Optics Letters 09/1997; 22(16):1247-9. · 3.40 Impact Factor
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ABSTRACT: Composite films containing solid state laser nanoparticles have been created which show optical amplification in the technologically important near IR range. The solid state laser materials studied, Cr-forsterite (Cr-Mg2SiO4) and Cr-diopside (Cr-CaMgSi2O6), were prepared using a dispersion polymerized polymer precursor. The nanoparticles produced during the polymer synthesis acted as size templates, creating fine crystalline powders of the Cr-forsterite and Crdiopside upon calcination. These fine powders were dispersed in a refractive index matched polymer matrix and cast as 5–10 μm thick films. The resulting composite containing Cr-forsterite showed optical amplification of 300 dB/m at 1.24 μm.
MRS Proceedings. 12/1995; 435.
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ABSTRACT: We describe a diode-pumped Cr{sup 4+}:YAG laser operating at 1.45 {mu}m. The laser outputs xxx mW when pumped by a 2 W single-transverse-mode 980 nm InGaAs diode.
06/1995
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ABSTRACT: Cr-doped lasers, based on forsterite and YAG, provide broadly
tunable power in the 1.25-μm and 1.45-μm regions. Performance data
on tuning range, pumping, output power, and thermal management for these
lasers is reviewed. Potential new crystals for Cr<sup>4+</sup> should
have heavy atoms to reduce lattice phonon frequencies, a distorted
tetrahedral cage for the Cr<sup>4+</sup> ion, and possibly an octahedral
site for Cr<sup>3+</sup>. Possible materials include monticellite and
diopside
IEEE Journal of Selected Topics in Quantum Electronics 05/1995; · 3.78 Impact Factor
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ABSTRACT: A detailed description of the design and operational
characteristics of a regeneratively initiated, self-mode-locked
Cr:forsterite laser pumped by a continuous-wave Nd:YAG laser is given.
Without compensating for the intracavity positive group velocity
dispersion, regenerative acoustooptic modulation produced pulses of
between 41 and 6.5 ps (FWHM) at 1.23 μm with average output powers of
between 280 and 380 mW, respectively. Using intracavity negative
group-velocity-dispersion compensation, nearly transform-limited
femtosecond pulses of 48 fs (FWHM) duration were generated with average
TEM<sub>00</sub> output powers of 380 mW at 1.23 μm. By tuning the
output of the mode-locked laser from 1.211 to 1.264 μm, the
dispersion (second and third order) of the Cr:forsterite gain medium has
been measured. The operational wavelength range of the laser was
extended to the visible region from 605 to 635 nm by external frequency
doubling in a LiIO<sub>3</sub> nonlinear crystal. With approximately 250
mW of fundamental pump power at 1.23 μm, red pulses of 116 fs (FWHM)
duration at 615 nm were obtained with conversion efficiencies
approaching 10 percent
IEEE Journal of Quantum Electronics 09/1994; · 1.88 Impact Factor
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ABSTRACT: Continuous-wave self-mode-locked operation of a chromium-doped YAG laser pumped by a continuous-wave Nd:YAG laser at 20 degrees C is described. We used both regenerative initiation and continuous-wave self-mode-locking techniques to generate nearly transform-limited pulses of 120-fs (FWHM) duration at 1.52 microm. The TEM(00) output power was as high as 360 mW. The output of this femtosecond source was tunable from 1.51 to 1.53 microm.
Optics Letters 03/1994; 19(6):390-2. · 3.40 Impact Factor
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ABSTRACT: The authors characterize continuous-wave operation of a
chromium-doped forsterite
(Cr<sup>4+</sup>:Mg<sub>2</sub>SiO<sub>4</sub>) laser using krypton ion,
Ti:sapphire, and Nd:YAG lasers as pump sources. Measurements were made
pumping at 647 nm and 676 nm with the krypton ion laser, between 690 and
1010 nm with the Ti:sapphire laser, and at 1.06 μm with the Nd:YAG
laser. Threshold pump powers and slope efficiencies are compared for
output coupler transmissions varying between 1 and 15.5%.
Room-temperature operation was only achieved using the Nd:YAG pump
laser. Forsterite laser output power as a function of both temperature
and pumping wavelength is discussed
IEEE Journal of Quantum Electronics 12/1993; · 1.88 Impact Factor
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ABSTRACT: A regeneratively initiated self-mode-locked chromium-doped forsterite laser operated at 3.5 degrees C is described. By employing intracavity negative-group-velocity dispersion compensation, nearly transform-limited femtosecond pulses of 48-fs (FWHM) duration were generated with average TEM(00) output powers of 380 mW at 1.23 microm. Regenerative initiation provides improvement in the output stability and ease of operation compared with fixed-frequency acousto-optic modulators. By tuning the mode-locked laser in the range 1.21-1.26 microm, estimated values for forsterite dispersion constants have also been obtained for the first time to our knowledge. The demonstrated power and stability open the door to applications such as efficient second-harmonic generation.
Optics Letters 05/1993; 18(10):826-8. · 3.40 Impact Factor
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ABSTRACT: Using an acousto-optically mode-locked chromium-doped forsterite laser, operated at 77 K and coupled to a nonlinear resonator containing a single-mode fiber, we have produced femtosecond pulses of 150-fs duration at 1.23 microm with useful output powers of approximately 60 mW This represents what is to our knowledge the first demonstration of femtosecond pulse generation from this laser system using the coupled-cavity mode-locking scheme.
Optics Letters 09/1992; 17(17):1216-8. · 3.40 Impact Factor
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ABSTRACT: We have obtained over 1.8 W of power from a cw chromium-doped forsterite laser operated at 77 K when it is pumped by a 7.3-W Nd:YAG laser at 1.06 microm. The forsterite laser tunes smoothly from 1.2 to 1.32 microm. At room temperature the output power decreases to approximately 35% of the cryogenic power level.
Optics Letters 11/1991; 16(21):1662-4. · 3.40 Impact Factor
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ABSTRACT: Since most fabricated waveguide lasers have approximately
rectangular guiding cross sections, a qualitative description of
propagation modes in such structures is given. Having developed the
concept of the effective mode index to be used in Fresnel reflection
coefficient calculations, the nonreciprocal mechanism due to the tilted
output facet is described. This is followed by an estimate of the
reciprocal-coupling loss introduced between the arms of the ring
waveguide due to the tilted output facet. It is shown that with
incidence angles approaching the critical angle, small tilt angles of
the output facet can produce a drastic difference between the intensity
reflectivities of the two oppositely sensed waves circulating in the
ring, thus creating a nonreciprocal mechanism which favors
unidirectional operation
Journal of Lightwave Technology 10/1991; · 2.78 Impact Factor
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ABSTRACT: A nonchemical 2*2 optical switch for fiber optic applications is described. Using a chiral-nematic liquid-crystal cell and switchable nematic liquid-crystal waveplates, the authors measured -26-dB crosstalk between unselected fibers, a fiber-to-fiber insertion losses of 1.4 dB, and switching times under 40 ms with operation at 1318 nm using 62.5/125- mu m multimode fiber. The device features simple construction, low power requirements, and an optical bandwidth suitable for LED or laser sources, and it works equally well with multimode or single-mode fiber.< >
IEEE Photonics Technology Letters 03/1990; · 2.19 Impact Factor
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ABSTRACT: The output of a tunable, additive-pulse, mode-locked NaCl:OH(-) color-center laser has been frequency doubled using a LiIO(3) crystal. With 100-fsec pulses generated at 1.6 microm, stable pulses as short as 76 fsec have been obtained with more than 5 mW of average output power at 0.8 microm. The frequency-doubled pulses are tunable from 755 to 825 nm.
Optics Letters 08/1989; 14(15):791-3. · 3.40 Impact Factor
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ABSTRACT: The operation of an additive-pulse mode-locked NaCl:OH(-) color-center laser is described. Stable output pulses as short as 75 fsec have been obtained. The laser is tunable from 1.51 to 1.65microm, with 300 mW of average output power at 1.6 microm.
Optics Letters 06/1989; 14(12):621-3. · 3.40 Impact Factor
