InP microdisk lasers on silicon wafer: CW room temperatureoperation at 1.6 μm

Microdisk lasers are fabricated in an InP:InGaAs MQW heterostructure transferred onto silicon. The CW room temperature laser operation of such devices at 1.6 μm is reported     

Triangular and hexagonal high Q-factor 2-D photonic bandgapcavities on III-V suspended membranes

We demonstrate InP-based triangular and hexagonal two-dimensional (2-D) planar photonic bandgap (PGB) crystal-based microcavities, positioned on a suspended membrane. Photoluminescence spectra of the structure clearly show well-resolved cavity modes, whose structure depends on the cavity shape. Q factors from 200 up to at least 900 are derived     

InP-based micromachined Mach-Zehnder interferometer stress sensors

 In the field of III–V-based compounds, new functionalities can be reached by integrating micromechanical structures with electro-optical functions, in order to fabricate Micro Opto Electro Mechanical Systems (MOEMS). A possible application is an InP-based integrated optical stress sensor. Such a system is based on a partly suspended waveguide that can be strained under the effect of an external stress. The photoelastic effect induces a phase shift that can be converted into an intensity shift of the signal if the device is configurated as a Mach-Zehnder interferometer. This system can be integrated monolithically with the optical source and the photodetector. The mechanical, photoelastic and optical properties of this structure has been simulated in order to configurate the alloy composition of the epitaxial layers and the geometry of the device. Micromachining processes have been developed in order to realize InP-based suspended microstructures by sacrificial layer etching and bulk micromachining. Preliminary results showed that the optical behaviour of the waveguides is close to the theoretical analysis. Characterisation of the complete interferometer is underway in our group. Received: 13 December 1996/Accepted: 18 December 1996     

Optical coupling between a two-dimensional photonic crystal-basedmicrocavity and single-line defect waveguide on InP membranes

We demonstrate the mutual coupling between a microcavity and a waveguide realized in a two-dimensional photonic crystal on an InP membrane. Coupling processes are evidenced by generating guided or cavity modes by photoluminescence and by measuring locally the diffraction losses. Depending on the transfer and loss dynamics, different coupling processes are found. Finite difference time-domain simulations and additional polarization resolved luminescence measurements are performed in order to further investigate the coupling procedure     

Tunable microcavity based on InP/air Bragg mirrors

A tunable Fabry–Perot filter based on InP/air Bragg mirrors has been studied. We have measured a resonance linewidth of 0.6 nm and a tuning range of 62 nm. The linewidth is kept below 1 nm over a 40 nm tuning range. The relation between the bending of the suspended layers during the actuation and the optical properties of the filter are analysed.     

Design and growth investigations of strainedInxGa1-xAs/InAlAs/InP heterostructures for highelectron mobility transistor application

Strained In_xGa_1-xAs/InAlAs modulation-doped heterostructures on InP have been studied theoretically and experimentally. Simulations based on self-consistently solving the Schrodinger-Poisson equations have been performed to investigate the influeuce of the design parameters, namely the layer thicknesses and the doping level in the barrier layer, on the carrier concentration n, in the channel. Modulation-doped heterostructures with a 100 Å strained indium-rich channel have been grown by molecular beam epitaxy for different indium compositions and growth temperatures. The highest performances in terms of n,×μ parameter, have been obtained for an indium concentration of 75% in the channel, at a growth temperature of 500°C. For higher indium concentration, the mobility drops sharply, which correlates with formation of misfit dislocations in the channel, observed on transmission electron microscopy micrographs of these structures. For an indium concentration of 75%, the mobility has been improved, first, by using a low V/III beam equivalent pressure ratio, that produces a close to stoichiometry material, second by using interface growth interruption under cation stabilization to reduce the interface roughness. HEMT devices have been processed on these heterostructures. The static I-V characteristics of 2×150 μm ² transistors revealed a 66% increase of the transconductance when the channel indium concentration is increased from 53% to 75%     

Enhanced localized near field and scattered far field for surface nanophotonics applications

The scattering physics of photons is traced back to Rayleigh scattering theory in 1871 and Mie scattering theory in 1908. However, the scattering near field and far field have recently emerged again as a new fundamental physics and innovative nanoprocessing technology in quantum electronics and photonic devices. An enhanced near field generated by plasmonic particles can concentrate optical energy into a nanoscale space as a nanolens even with near infrared laser pumping. This plasmonic nanophotonics extends the existing optical science to a new class of photonics inclusive of surface enhanced Raman scattering, nanoprocessing of advanced electronic and photonic materials, etc. The Mie scattering near field also opens up new fields. The Anderson localization of light in a planar random photonic crystal laser is also a new class of quantum electronics devices, where Slow Bloch Mode is scattered by artificial structural randomness in a photonic crystal. In this contribution we will review the recent efforts of our scattering photonics research, which have resulted in significant advances in the plasmonic surface photonics of near-field and far-field nano/micro photonics and the Anderson localization in random lasing.     

Broadband and compact 2-D photonic crystal reflectors with controllable polarization dependence

Two-dimensional (2-D) compact photonic crystal reflectors on suspended InP membranes were studied under normal incidence. We report the first experimental demonstration of 2-D broadband reflectors (experimental stopband superior to 200 nm, theoretical stopband of 350 nm). They are based on the coupling of free space waves with two slow Bloch modes of the crystal. Moreover, they present a very strong sensitivity of the polarization dependence, when modifying their geometry. A compact (50/spl times/50 /spl mu/m/sup 2/) demonstrator was realized and characterized, behaving either as a broadband reflector or as a broadband transmitter, depending on the polarization of the incident wave. Experimental results are in good agreement with numerical simulations.     

InP bonded membrane photonics components and circuits: toward 2.5 dimensional micro-nano-photonics

The general objective of this presentation is to demonstrate the great potential of III-V semiconductor -membrane photonic devices, with a special emphasis on InP and related materials in the prospect of new developments in the field of micro-nano-photonics. Various classes devices will be presented, which will have the communality of being based on the use of high index contrast structuration of semiconductor materials. The structuration is achieved vertically for the first class, by forming thin semiconductor membranes surrounded by low optical index material, or laterally for the second class via a two-dimensional (2-D) lateral structuration of the membranes (thus, resulting in 2-D photonic crystal (PC) structures); both structurations are also combined, according to a "2.5-dimensional" approach, which should broaden considerably the combinations of functionality beyond those presently contemplated with the two first classes. The general technological scheme of the membrane approach is fully compatible with planar technology which is widely in use in the world of silicon microelectronics and with heterogeneous integration of III-V active microphotonic devices with silicon microphotonics and microelectronics (e.g., molecular bonding of InP active membranes on silica on silicon substrate). A variety of devices will be presented, featuring micro-lasers based on 2-D PC micro-cavities as well as on 2-D Bloch modes (2-D distributed-feed-back micro-laser) for in plane and surface emission.     

Compact 1.55 /spl mu/m room-temperature optically pumped VCSEL using photonic crystal mirror

Reported is the first realisation of a novel vertical cavity surface emitting laser (VCSEL), in which one of the Bragg mirrors is entirely replaced by a single-layer photonic crystal mirror (PCM). The presence of the PCM considerably enhances the vertical compactness of the device. Room-temperature singlemode laser emission has been obtained at 1.55 mum by optical pumping (pulsed regime), with a threshold power around 15 mW