Ultra-wideband flat anomalous dispersion in nanostructured silicon membrane waveguides (Conference Presentation)
Thi Thuy Duong DinhJianhao ZhangMiguel Montesinos‐BallesterXavier Le RouxChristian LafforgueDaniel BenedikovičPavel ChebenÉric CassanDelphine Marris‐MoriniG. MaisonsMathieu CarrasS. CrémerS. MonfrayF. BœufLaurent VivienCarlos Alonso‐Ramos
0
Citation
0
Reference
10
Related Paper
Abstract:
The Si transparency (1.1 μm – 8 μm wavelength) contains the strongest absorption features of a wide range of chemical and biological substances. However, the use of SOI in the mid-IR is hampered by the large absorption of the buried oxide (BOX) for wavelengths above 4 μm. Silicon membranes have garnered great interest for their unique capability to overcome the BOX limitation while leveraging the advantages of Si photonics. On the other hand, silicon is uniquely poised for the implementation of wideband mid-IR sources based on nonlinear frequency generation. Promising supercontinuum and frequency comb generation have already been demonstrated in Si. Still, current implementations have a limited flexibility in the engineering of phase-matching conditions and dispersion, which complicates the shaping of the nonlinear spectrum. Patterning Si with features smaller than half of the wavelength (well within the capabilities of standard large-volume fabrication processes) has proven to be a simple and powerful tool to implement metamaterials with optimally engineered properties. Here, we present the design of nanostructured silicon membrane waveguides with ultra-wideband flat anomalous dispersion in a wavelength span exceeding 5 µm. Our three-dimensional finite difference time domain (FDTD) calculations predict flat anomalous dispersion near 50 ps/km⋅nm between 2.5 µm and 8 µm wavelength. These results illustrate the potential of subwavelength metamaterial engineering to control chromatic dispersion in Si membrane waveguides. This is a promising step towards the implementation of wideband nonlinear sources in the mid-IR for silicon photonics.Keywords:
Wideband
Supercontinuum
Supercontinuum generation is a phenomenon ofsignal spectrum broadening, due to the interplay between nonlinear and dispersive effects of the nonlinear medium. This phenomenon has been the subject of numerous studies in different mediums, due to its wide range of applications in a number of fields, such as tomography, metrology, spectroscopy, biomedical optics and in the field of optical telecommunications. For the analysis and modeling of the supercontinuum characteristics, it is crucial to select a medium in which signal propagation and supercontinuum generation are performed. For the application of supercontinuum in the field of optical telecommunications, optical fibers of the specific microstructure, i.e.PCF (Photonic Crystal Fiber) fibers are used, due to the high nonlinearity and the ability to model its dispersion profile, by modeling the structure of the fiber itself. In addition to the dispersive and nonlinear characteristics of the fiber, characteristics of the supercontinuum spectrum depend on a number of input signal parameters, such as wavelength, power, shape and duration of the input pulse. These parameters significantly influence the dynamics of the supercontinuum, in terms of the formation of processes responsible for the generation of supercontinuum, such as soliton fission, dispersive waves generation, self-phase modulation, etc. On the other hand, they also affect the width of the supercontinuum output spectrum and its coherence, which is crucial for supercontinuum applications in different fields.
This doctoral thesis presents the investigation of supercontinuum characteristics in PCF fibers of different dispersion profiles, for different input signal parameters. Supercontinuum generation is performed at wavelengths corresponding to the first, second and third optical windows. The processes responsible for spectrum spread in different optical windows and dispersion regimes, for different values of the input parameters, are analyzed. Supercontinuum generation in PCF fibers is numerically investigated and the process itself was modeled by the nonlinear Schrodinger equation. Also, the thesis gives an overview of the probability of distribution of extreme events, RW (Rogue Wave) waves, in supercontinuum generated in the anomalous dispersion regime.
Furthermore, study was focused on determining the characteristics of the supercontinuumspectrum and its coherence in the anomalous and normal dispersive regime, in order to define the optimaldispersion regime, the type of PCF fiber and the input parameters of the signal, to obtain supercontinuum spectrum, suitable for use as a multi-wavelength optical source in WDM (Wavelength Division Multiplexing) systems.
Supercontinuum
Cite
Citations (0)
Mid-infrared supercontinuum has been widely used in biomedicine, spectroscopy and other fields. With the development of fluoride fiber, the output power of mid-infrared supercontinuum has gradually increased. In this paper, the supercontinuum generation system of InF3 fiber pumped by a supercontinuum laser with a spectral range of 1.9-2.6 μm is presented. By optimizing the cooling device, the supercontinuum laser with an output power of 26.2 W and an output spectral range of 1.95-4.5 μm is realized. To our knowledge, this is the first report of mid-infrared supercontinuum output with an average power exceeding 20 W in InF3 fiber.
Supercontinuum
Cite
Citations (0)
The numerical simulation based on the solution to the generalized nonlinear Schrödinger equation is used to analyze various regimes of the supercontinuum generation in optical fibers under pulsed and CW excitation. The time dependences of the supercontinuum intensity are studied, and the optimal generation regimes are discussed with respect to various applications of the supercontinuum.
Supercontinuum
Cite
Citations (13)
Abstract The generation of supercontinuum spectrum is a very complex nonlinear process. Based on the nonlinear Schrodinger equation (NLSE), the effect of initial chirp on supercontinuum generation is numerically studied by split-step Fourier (SSF) method. The positive chirp and negative chirp have different effects on the supercontinuum generation. The results show that the energy distribution of supercontinuum spectrum can be improved by selecting appropriate chirp value.
Supercontinuum
Chirp
Chirp spread spectrum
Cite
Citations (0)
We report structured interferometry features in femtosecond supercontinuum generated with power near to supercontinuum generation threshold. We argue that these structures arise from the coherent superposition of supercontinuum generated from different sources of supercontinuum as pulse split into two daughter pulses. Increase in input pulse energy creates several more temporal pulse fragments and disrupts interference resulting in the typical feature of continuous broad supercontinuum. Such an understanding of supercontinuum generation process is critical to the use of supercontinuum as the light source for use in understanding the time dynamics and imaging of bio systems.
Supercontinuum
Cite
Citations (0)
We have investigated the supercontinuum spectra generated in an irregularly microstructured elliptic core fiber, a fiber with an elliptic core surrounded by irregularly arranged air holes. The supercontinuum spectra are strongly dependent on the polarization direction of the linearly polarized input pulse because of the large ellipticity of the core caused by the irregularity of air holes. From the simulation results obtained by solving numerically the generalized nonlinear Schr\"odinger equation with the adaptive split-step Fourier method, we show that the supercontinuum spectra can be analyzed as the sum of two supercontinuum spectra for the respective fundamental modes of the elliptic core. The polarization-dependent supercontinuum spectra could be useful in the implementation of a tunable broadband source.
Supercontinuum
Cite
Citations (7)
Coherence of the supercontinuum generation have been experimentally investigated. A supercontinuum was produced in the pyrex glass plate with a 0.8 um coherence length. The degree of mutual coherence of 0.4 was measured. A supercontinuum source for coherent applications and generation of sub 10 fs pulse is presented.
Supercontinuum
Degree of coherence
Cite
Citations (2)
Supercontinuum generation incorporates many nonlinear effects. In our experiment, two supercontinuum pulses generated independently by ultrashort pulses form stable spatial interference fringes and a frequency comb appears with collinear time-delay pump pulses. The supercontinuum keeps phase-lock relationships of the pump beams. Small intensity variations in the pump and small inhomogeneities in the material do not lead to dramatic phase fluctuations in the generated supercontinuum. It is important for supercontinuum simulation and studying of supercontinuum frequency combs in bulk material.
Supercontinuum
Cite
Citations (0)
Prospect of mid-infrared supercontinuum generation using soft glass nonlinear fibers is presented. Potential of fluoride and tellurite glass as mid-infrared supercontinuum medium is clarified. Supercontinuum over 5 μm is demonstrated using a new chalcogenide MOF.
Supercontinuum
Chalcogenide glass
Cite
Citations (0)
Prospect of mid-infrared supercontinuum generation using soft glass nonlinear fibers is presented. Potential of fluoride and tellurite glass as mid-infrared supercontinuum medium is clarified. Supercontinuum over 5μm is demonstrated using a new chalcogenide MOF.
Supercontinuum
Cite
Citations (0)