P. Regreny

Design and Optimization of Electrically Injected InP-Based Microdisk Lasers Integrated on and Coupled to a SOI Waveguide Circuit

We have performed a numerical study involving the design and optimization of InP-based microdisk lasers integrated on and coupled to a nanophotonic silicon-on-insulator (SOI) waveguide circuit, fabricated through bonding technology. The theoretical model was tested by fitting it to the lasing characteristics obtained for fabricated devices, which we presented previously. A good fit was obtained using parameter values that are consistent with numerical simulation. To obtain optimized laser performance, the composition of the InP-based epitaxial layer structure was optimized to minimize internal optical loss for a structure compatible with efficient current injection. Specific attention was paid to a tunnel-junction based approach. Bending loss was quantified to estimate the minimum microdisk diameter. The coupling between the InP microdisk and Si waveguide was calculated as function of the bonding layer thickness, waveguide offset and waveguide width. To study the lateral injection efficiency, an equivalent electrical network was solved and the voltage-current characteristic was calculated. Based on these results, the dominant device parameters were identified, including microdisk thickness and radius, coupling loss and tunnel-junction p-type doping. These parameters were optimized to obtain maximum wall-plug efficiency, for output powers in the range 1-100 W. The results of this optimization illustrate the potential for substantial improvement in laser performance.

Ultimate vertical Fabry-Perot cavity based on single-layer photonic crystal mirrors.

Vertical Fabry Perot cavities (VFPC) have been extensively studied, especially for the realization of vertical-cavity surface emitting lasers (VCSELs). They are traditionally composed of two Distributed Bragg Reflectors (DBR) which reflectivity has to be sufficient in order to obtain highly resonant cavity, which is particularly necessary for laser emission in VCSELs. As a consequence, DBRs consist generally in very thick layer stacks. In this paper, we demonstrate the smallest conceivable high Q vertical Fabry-Perot cavity, using ultra-thin and highly-efficient photonic crystal slab mirrors instead of conventional DBRs, which enable moreover a control of the polarization.

Room temperature low-threshold InAs/InP quantum dot single mode photonic crystal microlasers at 1.5 μm using cavity-confined slow light

We have designed, fabricated, and characterized an InP photonic crystal slab structure that supports a cavity-confined slow-light mode, i.e. a bandgap-confined valence band-edge mode. Three dimensional finite difference in time domain calculations predict that this type of structure can support electromagnetic modes with large quality factors and small mode volumes. Moreover these modes are robust with respect to fabrication imperfections. In this paper, we demonstrate room-temperature laser operation at 1.5 mum of a cavity-confined slow-light mode under pulsed excitation. The gain medium is a single layer of InAs/InP quantum dots. An effective peak pump power threshold of 80 microW is reported.

Dual-wavelength laser for THz generation by photo-mixing

We present the design and the fabrication of a dual-wavelength micro-photonic resonator combining a photonic crystal membrane (PCM) and a vertical Fabry Perot (FP) cavity where the former is embedded in the latter. A strong optical coupling between a PCM Γ-point Bloch mode and a FP mode at the same frequency can be used to provide a dual-wavelength device with a frequency difference which is analysed in terms of modes overlapping. We propose and demonstrate a process flow that can be used to provide such a device. Optical reflectivity characterisation is presented for a monolithic device and photoluminescence dual-wavelength spontaneous emission is demonstrated in an extended vertical cavity. Finally the dual-mode laser emission stability is examined with numerical Monte Carlo simulation.

3D harnessing of light with photon cage

We report on design, simulation and fabrication of ultimate and compact 3D close-geometries optical microcavities. These are based on the extension of the so-called 2.5D nanophotonic approach where a quasi 3D control of the photons has been soon demonstrated by our group. A tight control of photons, spectrally and spatially, in a small air region inside a circular regular pattern of high index material-based nanopillars is demonstrated when adjusting the number of pillars, their diameters and the diameter of the pillar-circle. Bottom-up approach based on InP nanowires grown by molecular beam epitaxy and top-down approach based on high aspect ratio anisotropic etching have been developed for fabricating these optical microcavities.

Towards optical networks-on-chip with 200mm hybrid technology

Integrated components for optical networks-on-chip, including III–V microdisk lasers, photodetectors, and wavelength selective circuits, are all demonstrated using a complementary metal-oxide-semiconductor (CMOS) compatible III–V/silicon-oninsulator integration technology at 200mm wafer scale.

A single InP membrane disc cavity for both transmission and detection of 10Gb/s signals in on chip interconnects

We give proof of concept demonstrations for the use of a single InP membrane disc structure as both a directly modulated light source and photo-detector using a 27 −1 PRBS sequence at rates up to 10Gb/s.

InP membrane-based microlasers on silicon wafer: microdisks vs photonic crystal cavities

Microdisk and photonic crystal (PC) cavity lasers were fabricated on InP based heterostructures integrated on silicon wafers. Single InGaAs quantum well, multiple InGaAs quantum wells and InAs quantum wires are used as active layers. Laser emission is achieved on quantum well based microdisk and PC microcavities. A comparison is made between different combinations of microcavity shapes and active material.

50 fJ-per-bit, high speed, directly modulated light sources for on-chip optical data communications

By employing optical injection-locking the direct modulation bandwidth of a 10µm diameter disc laser is increased to 15GHz. In addition, modulation at 20Gb/s is demonstrated with only 1mW DC bias & 190mV data signals (50fJ/bit)

Towards Optical Networks-on-Chip Using CMOS Compatible III-V/SOI Technology

Integrated components for optical networks-on-chip, including III-V microdisk lasers, photodetectors, and wavelength selective circuits, are all demonstrated using a co mplementary metal-oxide-semiconductor (CMOS) compatible III-V/silicon-oninsulator integration technology at 200mm wafer sca le. Keywords—silicon photonics; microdisk lasers and phot odetectors; heterogeneous integration; network-on-chip