Saturation of the Raman amplification by self-phase modulation in silicon nanowaveguides

We experimentally show that the self-phase modulation of picosecond pump pulses, induced by both the optical Kerr effect and free-carrier refraction, has a detrimental effect on the maximum on-off Raman gain achievable in silicon on insulator nanowaveguides, causing it to saturate. A simple calculation of the Raman gain coefficient from the measured broadened output pump spectra perfectly matches the saturated behavior of the amplified Raman signal observed experimentally at different input pump powers.Comment: Accepted for publications in Applied Physics Letter

Light localization induced enhancement of third order nonlinearities in a GaAs photonic crystal waveguide

Nonlinear propagation experiments in GaAs photonic crystal waveguides (PCW) were performed, which exhibit a large enhancement of third order nonlinearities, due to light propagation in a slow mode regime, such as two-photon absorption (TPA), optical Kerr effect and refractive index changes due to TPA generated free-carriers. A theoretical model has been established that shows very good quantitative agreement with experimental data and demonstrates the important role that group velocity plays. These observations give a strong insight into the use of PCWs for optical switching devices.Comment: 6 page

Fourier transformed picosecond synchronously pumped optical parametric oscillator without spectral filtering element

An optical parametric oscillator for the infrared region pumped by a picosecond Ti:Sapphire laser is demonstrated. Fourier transform limited pulses of 15 and 10 ps, for signal and idler wavelengths respectively, have been obtained using a periodically poled stoechiometric lithium tantalate nonlinear crystal, without any spectral filtering. A complete experimental study of the influence of the cavity length detuning on the spectral and temporal dynamic of the output radiation is discussed

Monolithic Solid-State Lasers for Spaceflight

A new solution for building high power, solid state lasers for space flight is to fabricate the whole laser resonator in a single (monolithic) structure or alternatively to build a contiguous diffusion bonded or welded structure. Monolithic lasers provide numerous advantages for space flight solid state lasers by minimizing misalignment concerns. The closed cavity is immune to contamination. The number of components is minimized thus increasing reliability. Bragg mirrors serve as the high reflector and output coupler thus minimizing optical coatings and coating damage. The Bragg mirrors also provide spectral and spatial mode selection for high fidelity. The monolithic structure allows short cavities resulting in short pulses. Passive saturable absorber Q-switches provide soft aerturing fro spatial mode filtering and improved pointing stability. We will review our recent commercial and in-house developments toward fully monolithic solid state lasers

DBR and DFB lasers in neodymium-and ytterbium-doped photothermorefractive glasses

The first demonstration, to the best of our knowledge, of distributed Bragg reflector (DBR) and monolithic distributed feedback (DFB) lasers in photothermorefractive glass doped with rare-earth ions is reported. The lasers were produced by incorporation of the volume Bragg gratings into the laser gain elements. The need for environment-insensitive, compact, robust, narrow line laser sources has stimulated the development of hybrid devices, such as distributed Bragg reflector (DBR) lasers, in which a laser resonator is produced by Bragg mirrors incorporated in a gain element, or distributed feedback (DFB) lasers, in which a resonator is produced by a Bragg grating that occupies the whole gain element. The concept of DFB was first successfully applied to optically pumped dye lasers The PTR glass has composition (M%) The two last elements are responsible for initiation of the photostructural transformations in the glass and enable VBG recording. As it was demonstrated in our earlier studies Nd-and Yb-doped PTR glasses with 2 wt. % of Yb and Nd ions have been prepared. The measurements of emission spectra were carried out in these glasses using an Ocean Optics spectrometer when glass samples were excited with a diode laser emitting at 808 nm (in the case of Nd ions) and 915 nm (for Yb ones

Beam Reflection By Transversely Chirped Volume Bragg Grating

Transversely chirped volume Bragg grating (TCVBG) provides tunability of resonant wavelength in different designs of laser cavities. Resonant reflectivity suppression and quality deterioration of Gaussian beam reflected by TCVBG are calculated, together with spectral characteristics

Dbr And Dfb Lasers In Neodymium- And Ytterbium-Doped Photothermorefractive Glasses

The first demonstration, to the best of our knowledge, of distributed Bragg reflector (DBR) and monolithic distributed feedback (DFB) lasers in photothermorefractive glass doped with rare-earth ions is reported. The lasers were produced by incorporation of the volume Bragg gratings into the laser gain elements. A monolithic single-frequency solid-state laser with a linewidth of 250 kHz and output power of 150 mW at 1066 nm is demonstrated. © 2014 Optical Society of America

Ring Cavity Tunable Fiber Laser With External Transversely Chirped Bragg Grating

Application of the Transverse Chirped Bragg Grating (TCBG - a reflecting volume Bragg grating with continuously variable resonant wavelength across the aperture) for the narrowband tunable ring-cavity fiber laser is presented. The main advantage of the use of TCBG is that its linear translation allows continuous tuning of emission wavelength within 5-10 nm band. Yb doped fiber laser operating in the wavelength range of 1050-1055 nm of narrowband emission up to 2.3 W is demonstrated. © 2013 SPIE