Passive mode-locking in semiconductor lasers with saturable absorbers bandgap shifted through quantum well intermixing

Passive mode-locking in semiconductor lasers in a Fabry–Perot configuration with a bandgap blueshift applied to the saturable absorber (SA) section has been experimentally characterized. For the first time a fully post-growth technique, quantum well intermixing, was adopted to modify the material bandgap in the SA section. The measurements showed not only an expected narrowing of the pulse width but also a significant expansion of the range of bias conditions generating a stable train of optical pulses. Moreover, the pulses from lasers with bandgap shifted absorbers presented reduced chirp and increased peak power with respect to the nonshifted case

High Extinction Ratio Polarization Selective TE/TM Bragg Gratings Filters on Silicon-on-insulator

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High-extinction-ratio TE/TM selective Bragg grating filters on silicon-on-insulator

We report on the design and fabrication of TE and TM polarization selective Bragg grating filters in the form of sinusoidal perturbations on the waveguide sidewall and etched holes on the top of the waveguide, respectively. Combining the two geometries on a silicon-on-insulator waveguide resulted in Bragg grating filters with high extinction ratios of approximately 60 dB

High-extinction-ratio TE/TM selective Bragg grating filters on silicon-on-insulator

We report on the design and fabrication of TE and TM polarization selective Bragg grating filters in the form of sinusoidal perturbations on the waveguide sidewall and etched holes on the top of the waveguide, respectively. Combining the two geometries on a silicon-on-insulator waveguide resulted in Bragg grating filters with high extinction ratios of approximately 60 dB

Ultrafast pulse generation in semiconductor lasers

Integrated semiconductor laser devices are presented as extremely compact generators of ultra-short pulse trains. Control is demonstrated on a wide range of emission parameters including wavelength, pulse duration, repetition rate and emitted power. All device geometries require simple drive electronics, consisting of only constant current injection and reverse bias voltage control

Optimization of Epilayer and Grating Geometries for Narrow Linewidth DFB Lasers (Conference Presentation)

Due to the demand on accurate metrology applications, the request for stable and powerful semiconductor laser is strongly increasing. An accurate analysis and optimization of the epilayer active material and of complex Bragg grating geometries allows to design and fabricate narrow linewidth DFB lasers without limiting the power output range. This general approach is suitable for laser devices emitting in a wide wavelength range within visible and infrared and based on different material platforms, such as InP, GaAs or GaN. The fabricated devices exhibit linewidth as narrow as few hundreds kHz and power output in the range of few tens mW

Design of chirped-coupling sidewall Bragg gratings for narrow linewidth distributed feedback lasers

A chirped-coupling sidewall Bragg grating is proposed to mitigate the nonlinear effects that deteriorate the linewidth in DFB lasers operating at a high power and current regime. This novel grating geometry is analyzed and simulated to extract the optimal design parameters in terms of intra-cavity field distribution. Compared to lasers with uniform Bragg gratings, devices fabricated with a chirped-coupling grating are shown to operate in stable single mode operation over a wider current and power range and exhibit linewidth as narrow as 100 kHz

High accuracy transfer printing of single-mode membrane silicon photonic devices

A transfer printing (TP) method is presented for the micro-assembly of integrated photonic devices from suspended membrane components. Ultra thin membranes with thickness of 150nm are directly printed without the use of mechanical support and adhesion layers. By using a correlation alignment scheme vertical integration of single-mode silicon waveguides is achieved with an average placement accuracy of 100±70nm. Silicon (Si) μ-ring resonators are also fabricated and show controllable optical coupling by varying the lateral absolute position to an underlying Si bus waveguide

Transfer Printing of Photonic Nanostructures to Silicon Integrated Circuits

Optical systems require the integration of technologies fabricated on different materials. We use a transfer printing technique to integrate pre-processed III-V, polymer and silicon membrane devices onto passive optical circuits with nano-metric positional accuracy

Passive mode-locking in semiconductor lasers with saturable absorbers bandgap shifted through quantum well intermixing

Passive mode-locking in semiconductor lasers in a Fabry-Perot configuration with a bandgap blueshift applied to the saturable absorber (SA) section has been experimentally characterized. For the first time a fully post-growth technique, quantum well intermixing, was adopted to modify the material bandgap in the SA section. The measurements showed not only an expected narrowing of the pulse width but also a significant expansion of the range of bias conditions generating a stable train of optical pulses. Moreover, the pulses from lasers with bandgap shifted absorbers presented reduced chirp and increased peak power with respect to the nonshifted case