Orange-to-red tunable picosecond pulses by frequency doubling in a diode-pumped PPKTP waveguide

A compact picosecond all-room-temperature orange-to-red tunable laser source in the spectral region between 600 and 627 nm is demonstrated. The tunable radiation is obtained by second-harmonic generation in a periodically poled potassium titanyl phosphate (PPKTP) multimode waveguide using a tunable quantum-dot external-cavity mode-locked laser. The maximum second-harmonic output peak power of 3.91 mW at 613 nm is achieved for 85.94 mW of launched pump peak power at 1226 nm, resulting in conversion efficiency of 4.55%

What can optical engineers learn from Leonardo?

Optics in general is an old science. Many brilliant researchers have created both theory and practice in this field. Some of their achievements are still in use, some are unjustly forgotten. In this paper we tried to rethink some points of ancient scientists to show that they had «seeds» which are still important ourdays. In particular, the applicability of the "golden section" from nature to the modern, computational process of optical system design was tested experimentally. Design principles, current challenges, possible solutions and some applications are discussed. They could be used, for example, in optical design, at the stage of starting scheme or help making decision of optical system producibility

Wide-angle spectral imaging using a Fabry-Perot interferometer

We show that wide-angle spectral imaging can be achieved with compact and cost-effective devices using Fabry-Pérot interferometers. Designs with a full field of view of 90°, in which the Fabry-Pérot interferometer is mounted either in front of an imaging lens system or behind a telecentric lens system, are presented and analysed. We show the dependency of the spectral resolution on the numerical aperture of the lens system and demonstrate its value as a design criterion.ImPhys/Imaging PhysicsApplied Science

P-i-n junction quantum dot saturable absorber mirror:Electrical control of ultrafast dynamics

We report on nonlinear optical properties of a p-i-n junction quantum dot saturable absorber based on InGaAs/GaAs. Absorption recovery dynamics and nonlinear reflectivity are investigated for different reverse bias and pump power conditions. A decrease in absorption recovery time of nearly two orders of magnitude is demonstrated by applying a voltage between 0 and −20 V. The saturable absorber modulation depth and saturation fluence are found to be independent from the applied reverse bias

Ultra high speed submonolayer quantum-dot vertical-cavity surface-emitting lasers

980 nm ultra high speed vertical-cavity surface-emitting lasers based on dense arrays of triple stacked submonolayer grown quantum dots are realized. Single mode devices demonstrate at 20° C a -3dB modulation bandwidth of 16.6 GHz and a modulation current efficiency factor of 19 GHz/ mA. Multimode lasers shown clearly open eyes for 20 Gb/s data streams

20 Gb/s direct modulation of 980 nm VCSELs based on submonolayer deposition of quantum dots

980 nm vertical-cavity surface-emitting laser based on sub-monolayer growth of quantum dots show at 25 and 85°C for 20 Gb/s without current adjustment clearly open eyes and error free operation with bit error rates better than 10-12. For these multimode lasers the small signal modulation bandwidth decreases only from 15 GHz at 25°C to 13 GHz at 85°C. Single mode devices demonstrate at 20°C a small signal modulation bandwidth of 16.6 GHz with 0.8 mW optical output power and a record high modulation current efficiency factor of 19 GHz/mA1/2