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We experimentally demonstrate the possibility of tuning the frequency of a laser pulse via the use of an Airy pulse-seeded soliton self-frequency shift. The intrinsically asymmetric nature of Airy pulses, typically featured by either leading or trailing oscillatory tails (relatively to the main lobe), is revealed through the nonlinear generation of both a primary and a secondary Raman soliton self-frequency shift, a phenomenon which is driven by the soliton fission processes. The resulting frequency shift can be carefully controlled by using time-reversed Airy pulses or, alternatively, by applying an offset to the cubic phase modulation used to generate the pulses. When compared with the use of conventional chirped Gaussian pulses, our technique brings about unique advantages in terms of both efficient frequency tuning and feasibility, along with the generation and control of multicolor Raman solitons with enhanced tunability. Our theoretical analysis agrees well with our experimental observations. Airy pulses are ubiquitous in dispersive optical systems. Such pulses, whose temporal field envelope is described by an Airy function, can be formed by virtue of a cubic spectral phase imposed via either third order dispersion [1] or a pulse shaper. Their asymmetric pulse profiles lead to a variety of applications such as the generation of broadband spectra [2] and coherent control [3]. Airy pulses have attracted increasing attention since their unique dynamics including dispersion-free propagation and self-healing was uncovered in optics [4], finding inspiration from the world of quantum mechanics [5]. As a result, it has been possible, for example, to construct linear spatiotemporal optical bullets [6]. Extensive theoretical and numerical studies have been devoted to the study of the linear and nonlinear dynamics of these pulses under second and/or third order dispersion with or without the presence of a Kerr nonlinearity [7,8], as well as to the understanding of their interaction with solitons [9]. However, the experimental investigation of Airy pulses, with a view to elucidate their advantages with respect to conventional Gaussian-based pulses, is still relatively unexplored. The peculiar feature of Airy pulses is that their linear dynamics is exactly coded on their spectral phase, i.e., the cubic term [10], a feature that introduces additional controlling freedom. Nevertheless, such control is rarely applied in a practical framework, particularly under the influence of the higher order nonlinearities commonly seen in fiber or integrated optics [11,12]. Among those nonlinearities, stimulated Raman scattering (SRS) is the most fundamental, as it may play a critical role in many of the nonlinear phenomena occurring in fibers or waveguides. SRS brings asymmetric (in time) pulse dynamics strongly related to its temporally retarded nonlinear response, which enables a continuous downshift of the carrier frequency of a decelerating fundamental optical soliton-or, in other terms, a soliton self-frequency shift (SSFS) [13]...

We demonstrate laser induced cooling in ytterbium doped silica (SiO2) glass with alumina, yttria co-doping (GAYY-Aluminum: Yttrium: Ytterbium Glass) fabricated using the modified chemical vapour deposition (MCVD) technique. A maximum temperature reduction by − 0.9 K from room temperature (296 K) at atmospheric pressure was achieved using only 6.5 W of 1029 nm laser radiation. The developed fabrication process allows us to incorporate ytterbium at concentration of 4 × 1026 ions/m3 which is the highest value reported for laser cooling without clustering or lifetime shortening, as well as to reach a very low background absorptive loss of 10 dB/km. The numerical simulation of temperature change versus pump power well agrees with the observation and predicts, for the same conditions, a temperature reduction of 4 K from room temperature in a vacuum. This novel silica glass has a high potential for a vast number of applications in laser cooling such as radiation-balanced amplifiers and high-power lasers including fiber lasers.

We experimentally demonstrate tunable multiple-idler wavelength broadcasting of a signal to selective channels for wavelength division multiplexing (WDM). This is based on cascaded χ(2) nonlinear mixing process in a novel multiple-QPM 10-mm-long periodically poled LiNbO3 having an aperiodic domain in the center. The idlers' spacing is varied utilizing detuning of the pump wavelength within the SHG bandwidth. The temperature-assisted tuning of QPM pump wavelengths allows shifting the idlers together to different set of WDM channels. Our experimental results indicate that an overall idler wavelength shift of less than 10 nm realized by selecting pump wavelengths via temperature tuning, is sufficient to cover up to 40 WDM channels for multiple idlers broadcasting.

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