InP-based Photonic Devices Research Articles

Study of an Integration Platform Based on an Adiabatic Active-Layer Waveguide Connection for InP Photonic Device Integration Mirroring That of Heterogeneous Integration on Silicon

In this work, a photonic device integration platform capable of integration of active-passive InP-based photonic devices without the use of material regrowth is introduced. The platform makes use of an adiabatic active-layer waveguide connection (ALWC) to move an optical beam between active and passive devices. The performance of this platform is analyzed using an example made up of four main sections: (1) a fiber coupling section for enabling vertical beam coupling from optical fiber into the photonic chip using a mode-matched surface grating with apodized duty cycles; (2) a transparent waveguide section for realizing passive photonic devices; (3) an adiabatic mode connection structure for moving the optical beam between passive and active device sections; and (4) an active device section for realizing active photonic devices. It is shown that the coupled surface grating, when added with a bottom gold reflector, can achieve a high chip-to-fiber coupling efficiency (CE) of 88.3% at 1550 nm. The adiabatic active-layer mode connection structure has an optical loss of lower than 1% (CE > 99%). The active device section can achieve an optical gain of 20 dB/mm with the use of only 3 quantum wells. The optimized structural parameters of the entire waveguide module are analyzed and discussed.

Realization of freestanding InP membranes on Si by low-temperature wafer bonding and stress analysis using micro-Raman spectroscopy

We present a method to realize freestanding InP membranes on Si substrate by combination of low-temperature wafer bonding, layer transfer, and wet chemical release processes. The removal of InP substrate and sacrificial etching of an InGaAs layer defines the 2.0μm InP thin layer bonded to Si. The InP membranes are subsequently released by a two-step wet etching process and the surface stress profiling in these freestanding membranes has been carried out by high spectral resolution micro-Raman measurements. Realization of such micromechanical structures on Si platform would be suitable for the integration of InP-based photonic devices on large area Si-based microelectronic systems.

Transverse magnetic mode nonreciprocal propagation in an amplifying AlGaInAs∕InP optical waveguide isolator

The design, fabrication, and characterization of an amplifying transverse magnetic (TM)-mode optical waveguide isolator operating at a wavelength of 1300nm are presented. The magneto-optical Kerr effect induces nonreciprocal modal absorption in a semiconductor optical amplifier with a laterally magnetized ferromagnetic metal contact. Current injection in the active structure compensates for the loss in the forward propagation direction. Monolithic integration of this optical isolator configuration with active InP-based photonic devices is straightforward. The combination of AlGaInAs∕InP active material and the metal alloy Co50Fe50 results in greatly improved performance. 99dB∕cm TM mode isolation and significantly reduced insertion loss are demonstrated.

Novel optoelectronic simulation strategy of an ultra-fast InP/InGaAsP modulator

In this paper, we detail a new simulation strategy for the accurate prediction of the functionality of InP-based photonic devices. The device under analysis is simulated by means of a commercially available finite-element solver in order to exactly account for the distribution of carriers in the guiding region while another tool calculates the refractive index profile. Due to the semiconductor nature of the multilayer substrate, this is proved to be important in order to consider the effect of carriers in the depleted region that contributes, together with the linear and quadratic electric-field related ones to the overall refractive index change. In order to interface the two FEM solvers, an in-house linking code has been developed. Such a code computes the refractive optical index distribution from the results of the electrical device simulations. Moreover, it makes the grid used by the electrical solver compatible with the software adopted for the optical analysis. The errors related to grid interpolation are then eliminated. As an application, the functionalities of a InP/InGaAsP Mach-Zehnder modulator have been simulated. The presented numerical results, indicating a reverse bias voltage of 5.5V for a 180° phase shift in a 2-mm-long device, are confirmed by measured data. Transient simulations predict that the analyzed structure is eligible for 40Gbit/s operation.

InAs/InP quantum dots emitting in the [formula omitted] wavelength region by inserting ultrathin GaAs and GaP interlayers

We present an effective method to tune the emission wavelength of InAs/InP(1 0 0) quantum dots (QDs) in the 1.55 μ m wavelength region. The InAs QDs are embedded in lattice-matched GaInAsP which is the waveguide core material in InP-based photonic devices. By inserting ultrathin GaAs (0.3–2.5 monolayers (MLs)) or GaP (0.3–1.1 MLs) layers between the QDs and the GaInAsP buffer, continuous wavelength tuning from above 1.60 μ m to below 1.5 μ m at room temperature is demonstrated by varying solely one growth parameter, i.e., the interlayer thickness. The thin GaAs and GaP interlayers play an important role in suppressing As/P exchange and consuming surface-segregated In, leading to drastic reduction of the emission wavelength of the InAs QDs.

Low-threshold, high-power, 1.3-/spl mu/m wavelength, InGaAsP-InP etched-facet folded-cavity surface-emitting lasers

A 1.3-μm wavelength, InGaAsP-InP folded-cavity, surface-emitting laser with CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> -H <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> reactive ion-etched vertical and 45/spl deg/ angled facets was demonstrated for the first time. Continuous-wave threshold currents of 32 mA have been achieved, with >15 mW CW power for the surface-emitted light. These surface-emitting lasers with two dry-etched facets are suitable for wafer-level testing and for monolithic integration with other InP-based photonic devices.

Pt/Ti Low Resistance Non-Alloyed Ohmic Contacts to InP-Based Photonic Devices

ABSTRACTPt/ri low resistance non-alloyed ohmic contacts to p-InP-based contact layers in photonic devices, which were formed by rapid thermal processing (RTP), were studied. E-gun evaporated Pt/Ti metallization deposited onto 1.5· 1019 cm−3 Zn doped In0.53Ga0.47 As yielded the best electrical performance. These contacts were ohmic as deposited with a specific contact resistance value of 3.0 · 10−4 Ωcm2. RTP at higher temperatures led to decrease of the specific contact resistance to 3.4 · 10−8 Ωcm2 (0.08Ωmm) as a result of heating at 450°C for 30 sec. This heat treatment caused only a limited interfacial reaction (about 20 nm thick) between the Ti and the InGaAs, resulted in a thermally stable contact and induced tensile stress of 5.6 · 109 dyne · cm−2 at the metal layer but without degrading the adhesion. Heating at temperatures higher than 500°C resulted in an extensive interaction and degradation of the contact.