Massachusetts Institute of Technology

Pendar Technologies, LLC

Christine A Wang

James N Walpole

Stephen R Chinn

Emily S Kintzer

Laurent Diehl

Anish K Goyal

Mark Francis Witinski

Christian Pfluegl

Leo J Missaggia

William D Goodhue

Joseph P Donnelly

Hong K Choi

Robert A Brown

James W Caunt

Kurt Rauschenbach

Lee J Missaggia

Photonic integrated circuits (PICs) are based on quantum cascade (QC) structures. In embodiment methods and corresponding devices, a QC layer in a wave confinement region of an integrated multi-layer semiconductor structure capable of producing optical gain is depleted of free charge carriers to create a low-loss optical wave confinement region in a portion of the structure. Ion implantation may be used to create energetically deep trap levels to trap free charge carriers. Other embodiments include modifying a region of a passive, depleted QC structure to produce an active region capable of optical gain. Gain or loss may also be modified by partially depleting or enhancing free charge carrier density. QC lasers and amplifiers may be integrated monolithically with each other or with passive waveguides and other passive devices in a self-aligned manner. Embodiments overcome challenges of high cost, complex fabrication, and coupling loss involved with material re-growth methods.

Methods for forming photonic integrated circuits based on quantum cascade structures

Photonic integrated circuits based on quantum cascade structures

A semiconductor laser oscillator structure and method is described having a tapered gain region in one-half of a laser cavity and a confocal oscillator region in another half of the cavity. An aperture is formed between two pairs of cavity spoilers located between the two cavity halves. One pair of spoilers is provided for receiving light which is reflected off of an output facet back into the semiconductor and removing it from the gain region. The other pair of spoilers removes light reflected from a curved mirror surface formed at the end of the other laser cavity half.

Tapered semiconductor laser oscillator

A semiconductor laser gain structure having a tapered gain region comprising cavity spoilers for receiving light which is reflected off of the output facet back into the semiconductor and removing it from the gain region so as to reduce or eliminate self-oscillation. The boundaries of the gain region are also designed to have a very low refractive index gradient so as to minimize reflection of light off of the boundaries back into the gain region. The gain structure may be embodied in a semiconductor laser oscillator or semiconductor laser amplifier depending on whether the input facet is or is not, respectively, anti-reflection coated. The output facet is anti-reflection coated in either embodiment.

Tapered semiconductor laser gain structure with cavity spoiling grooves

A semiconductor laser gain structure having a tapered gain region comprising cavity spoilers for receiving light which is reflected off of the output facet back into the semiconductor and removing it from the gain region so as to reduce or eliminate self oscillation. The boundaries of the gain region are also designed to have a very low refractive index gradient so as to minimize reflection of light off of the boundaries back into the gain region. The gain structure may be embodied in a semiconductor laser oscillator or semiconductor laser amplifier depending on whether the input facet is or is not, respectively, anti reflection coated. The output facet is anti-reflection coated in either embodiment.

A strained quantum-well diode laser with an AlInGaAs active layer and AlGaAs cladding and/or confining layers on a GaAs substrate is provided. AlInGaAs/AlGaAs lasers can be configured in laser geometries including ridge, waveguide, buried heterostructure, oxide-defined, proton-defined, narrow-stripe, broad-stripe, coupled-stripe and linear arrays using any epitaxial growth technique. Broad-stripe devices were fabricated in graded-index separate confinement heterostructures, grown by organometallic vapor phase epitaxy on GaAs substrates, containing a single Al.sub.y In.sub.x Ga.sub.l-x-y As quantum well with x between 0.14 and 0.12 and y between 0.05 and 0.17. With increasing Al content, emission wavelengths from 890 to 785 nm were obtained. Threshold current densities, J.sub.th 's, less than 200 A cm.sup.-2 and differential quantum efficiencies in the range 71 to 88 percent were observed.

Reliable AlInGaAs/AlGaAs strained-layer diode lasers

A gaseous mixture is introduced through a radial inlet into a plenum-like antichamber above a porous diaphragm mounted across the top of a reactor vessel of substantially uniform width. The antichamber and diaphragm are substantially coextensive with the width of the vessel. The diaphragm may form part of a removable cover/diaphragm unit received in a collar-like ring. The substrate holder includes a molybdenum cap and base which fits over a pedestal of refractory material carrying a temperature sensor with an electrical lead extending down the hollow core of a rotatable reactor

Vapor phase reactor for making multilayer structures

An improved two-dimensional semiconductor surface-emitting laser array is described in which two intra-cavity internal reflecting surfaces are formed at a 45.degree. angle to the plane of the active layer of the semiconductor laser so as to internally reflect light from each end of the active layer in a direction normal to the plane of the active layer with a buried reflective mirror provided in the path of one of said reflections, so as to transmit reflected light back through the laser and out the top surface of the array.

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Bedford, MA, United States of America

Christine A Wang