All-fiber fourth and fifth harmonic generation from a single source

All-fiber fourth and fifth harmonic generation from a single source is demonstrated experimentally and analyzed theoretically. Light from a fully fiberized high power master oscillator power amplifier is launched into a periodically poled silica fiber generating the second harmonic. The output is then sent through two optical microfibers that generate the third and fourth harmonic, respectively, via four wave mixing (FWM). For a large range of pump wavelengths in the silica optical transmission window, phase matched FWM can be achieved in the microfibers at two different diameters with relatively wide fabrication tolerances of up to ±5 nm. Our simulations indicate that by optimizing the second harmonic generation efficiency and the diameters and lengths of the two microfibers, conversion efficiencies to the fourth harmonic in excess of 25% are theoretically achievable

Distortion in linearized electrooptic modulators

Intermodulation and harmonic distortion are calculated for a simple fiber-optic link with a representative set of link parameters and a variety of electrooptic modulators: simple Mach-Zehnder, linearized dual and triple Mach-Zehnder, simple directional coupler (two operating points), and linearized directional coupler with one and two dc electrodes. The resulting dynamic ranges, gains, and noise figures are compared for these modulators. A new definition of dynamic range is proposed to accommodate the more complicated variation of intermodulation with input power exhibited by linearized modulators. The effects of noise bandwidth, preamplifier distortion, and errors in modulator operating conditions are described

Triple correlation for detection of damage-related nonlinearities in composite structures

Nonlinear effects in vibration responses are investigated for the undamaged composite plate and the composite plate with a delamination. The analysis is focused on higher harmonic generation in vibration responses for various excitation amplitude levels. This effect is investigated using the triple correlation technique. The dynamics of composite plate was modelled using two-dimensional finite elements and the classical lamination theory. The doubled-node approach was used to model delamination area. Mode shapes and natural frequencies were estimated based on numerical models. Next, the delamination divergence analysis was used to obtain relative displacements for delaminated plies. Experimental modal analysis test was carried out to verify the numerical models. The two strongest vibration modes as well as two vibration modes with the smallest and largest motion level of delaminated plies were selected for nonlinear vibration test. The Fisher criterion was employed to verify the effectiveness and confidence level of the proposed technique. The results show that the method can be used not only to reveal nonlinearities, but also to reliably detect impact damage in composites. These results are confirmed using the statistical analysis

Multi-component optical solitary waves

We discuss several novel types of multi-component (temporal and spatial) envelope solitary waves that appear in fiber and waveguide nonlinear optics. In particular, we describe multi-channel solitary waves in bit-parallel-wavelength fiber transmission systems for high performance computer networks, multi-colour parametric spatial solitary waves due to cascaded nonlinearities of quadratic materials, and quasiperiodic envelope solitons due to quasi-phase-matching in Fibonacci optical superlattices.Comment: 12 pages, 11 figures; To be published in: Proceedings of the Dynamics Days Asia-Pacific: First International Conference on Nonlinear Science (Hong-Kong, 13-16 July, 1999), Editor: Bambi Hu (Elsevier Publishers, 2000

High-power, continuous-wave, scalable, single-frequency 852nm laser source for 213nm generation

We developed a high-power, continuous-wave (CW), single-frequency 852nm laser source, for the purpose of fourth harmonic generation at 213nm. Our approach is the doubly resonant sum-frequency mixing (DRSFM) with two fiber sources. An in-house single-frequency master oscillator at 1907nm is amplified by an in-house clad-pumped amplifier to 5W, and a commercial single-frequency master oscillator at 1540nm is amplified by a commercial amplifier to 10W. The two beams are combined via a dichroic mirror to a single beam before incident on a dual-wavelength resonator, consisting of one set of dual-wavelength mirrors. The external resonator is locked to the 1907nm laser frequency, and the frequency of the 1540nm is locked to the resonator, realizing double-resonance. With a periodically-poled stoichiometric lithium tantalate in the resonator, the sum-frequency at 852nm is efficiently generated. All 3 waves are in the same polarization (e-ray), allowing the effective use of Brewster-cut device, eliminating reflection loss for all wavelengths without any antireflection coatings. With 4.6W at 1907nm and 7.7W at 1540nm incident onto the resonator, 5.2W at 852nm was generated, representing the efficiency of greater than 40%. The experimental result indicates our current setup will be more efficient with higher input powers at 1907nm. With both fiber sources at 1540nm and 1907nm being scalable in output power, the output at 852nm is also scalable. By the forth harmonic of 852nm, 0.456 W CW 213nm was generated.New Energy and Industrial Technology Development Organization (NEDO) of JapanThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Solid-State Laser Source of Tunable Narrow-Bandwidth Ultraviolet Radiation

A solid-state laser source of tunable and narrow-bandwidth UV light is disclosed. The system relies on light from a diode laser that preferably generates light at infrared frequencies. The light from the seed diode laser is pulse amplified in a light amplifier, and converted into the ultraviolet by frequency tripling, quadrupling, or quintupling the infrared light. The narrow bandwidth, or relatively pure light, of the seed laser is preserved, and the pulse amplifier generates high peak light powers to increase the efficiency of the nonlinear crystals in the frequency conversion stage. Higher output powers may be obtained by adding a fiber amplifier to power amplify the pulsed laser light prior to conversion