Wavelength stability in a hybrid photonic crystal laser through controlled nonlinear absorptive heating in the reflector

Abstract

The need for miniaturized, fully integrated semiconductor lasers has stimulated significant research efforts into realizing unconventional configurations that can meet the performance requirements of a large spectrum of applications, ranging from communication systems to sensing. We demonstrate a hybrid, silicon photonics-compatible photonic crystal (PhC) laser architecture that can be used to implement cost-effective, high-capacity light sources, with high side-mode suppression ratio and milliwatt output output powers. The emitted wavelength is set and controlled by a silicon PhC cavity-based reflective filter with the gain provided by a III–V-based reflective semiconductor optical amplifier (RSOA). The high power density in the laser cavity results in a significant enhancement of the nonlinear absorption in silicon in the high Q-factor PhC resonator. The heat generated in this manner creates a tuning effect in the wavelength-selective element, which can be used to offset external temperature fluctuations without the use of active cooling. Our approach is fully compatible with existing fabrication and integration technologies, providing a practical route to integrated lasing in wavelength-sensitive schemes.

Experimental Demonstration of Ultrafast THz Modulation in a Graphene-Based Thin Film Absorber through Negative Photoinduced Conductivity

“…It is found that photoexcitation dynamically modulates the conductivity of the graphene sheet in the sample with decay of 2.79 ps, resulting in absorption tuning on the order of 40%. The time scale is comparable and even smaller with respect to other emerging or established platforms; 30 − 32 that is, a germanium-based metasurface with a full recovery time of 17 ps has been recently demonstrated. 31 Our system holds additionally the advantage of the 2D nature of the material, which is ideal for the realization of minimized components.…”

Model of thermo-optic nonlinear dynamics of photonic crystal cavities

“…Recent advances in light confinement at the wavelength scale are leading to smaller and smaller high-performance resonators fabricated on silicon-on-insulator platforms. Specifically, spherical cavities [6], toroidal cavities [7,8], and photonic crystal (PhC) cavities [9][10][11][12][13][14] offer very low optical losses [i.e., high quality (Q) factors [15]], low coupling losses [16], and small mode volumes in the range of λ 3 , and enable the investigation of cavity quantum electrodynamics [17], all-optical computing [18], lasing and parametric oscillations [19][20][21], and enhanced nonlinear processes [22,23]. The wavelength scale confinement of light in microcavities leads to a huge enhancement of the relatively small optical nonlinearities of silicon [24].…”

Edge-Coupling of O-Band InP Etched-Facet Lasers to Polymer Waveguides on SOI by Micro-Transfer-Printing

“…Full butt-coupling and accurate vertical alignment makes mode matching between the laser and the polymer waveguide easier compared to printing the laser at the top of the SOI and adjust the thickness of the polymer to align the waveguides. The polymer waveguide can act as an optical link to other optical functions of a photonic circuit or it can be used to evanescently couple the light to a tapered SOI waveguide for hybrid polymer-SOI photonics [35] or to realize advanced lasers [6]. The configuration allows the recess facet to be positioned far from the tip of the SOI taper, preventing damaging the taper during the etch process.…”

“…Mode mismatch is the major source of the insertion losses in edge-coupling, which is overcome by the use of mode size converters (MSC) and tight alignment tolerances. Reflective semiconductor optical amplifier (RSOA) chips have been edge-coupled to silicon photonics in external cavity laser configuration, with no need of MSC nor wafer bonding but still needing precise alignment [5], [6]. The edge coupling of fully packaged lasers on chip has been reported [7]- [10].…”