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

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 photonicscompatible 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.

Optimizing an interleaved p-n junction to reduce energy dissipation in silicon slow-light modulators

Reducing power dissipation in electro-optic modulators is a key step for widespread application of silicon photonics to optical communication.In this work,we design Mach–Zehnder modulators in the silicon-on-insulator platform,which make use of slow light in a waveguide grating and of a reverse-biased p-n junction with interleaved contacts along the waveguide axis.After optimizing the junction parameters,we discuss the full simulation of the modulator in order to find a proper trade-off among various figures of merit,such as modulation efficiency,insertion loss,cutoff frequency,optical modulation amplitude,and dissipated energy per bit.Comparison with conventional structures(with lateral p-n junction and/or in rib waveguides without slow light)highlights the importance of combining slow light with the interleaved p-n junction,thanks to the increased overlap between the travelling optical wave and the depletion regions.As a surprising result,the modulator performance is improved over an optical bandwidth that is much wider than the slow-light bandwidth.