Electro optic modulator
AssigneeBookham Technology PLC
InventorsEmma Jane Clarissa Dawnay, Arnold Peter Roscoe Harpin, Ian Edward Day
Life of this patent
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Abstract
A doped slab region is described for use around a ridge waveguide, for controlling the refractive index of the waveguide material. Instead of simply diffusing dopant in from a surface of the slab region adjacent the waveguide, an area of the slab region is etched and dopant diffused in from a side face of the etched region. Thus, the dopant profile is established from a horizontal direction, allowing the profile to be controlled. A simple vertically uniform doping profile can thus be provided, leading to a vertically uniform current density, or an anisotropic wet etch can be applied after the initial etch to provide a profile which concentrates the current density at a selected height in the slab region.
Claims23
An electro-optic device comprising a ridge waveguide formed on a slab region extending to either side thereof and containing a doped region, the slab region defining a plane, thereby to form a conductive path across the waveguide, the doped region being bounded on at least two sides by confining layers of oxide, the confining layers being of different material to the slab region, wherein the doped region extends from one of said confining layers of oxide to another of said confining layers of oxide throughout the depth of the slab region in a direction substantially perpendicular to said plane.
An electro-optic device comprising a ridge waveguide formed on a slab region extending to either side thereof and containing a doped region, the slab region defining a plane, thereby to form a conductive path across the waveguide, wherein the doped region is bounded on at least two sides by confining layers of oxide, has a substantially uniform distribution in a direction perpendicular to said plane and extends from one of said confining layers of oxide to another of said confining layers of oxide throughout the depth of the slab region in a direction substantially perpendicular to said plane.
An electro-optic device comprising a ridge waveguide formed on a slab region extending to either side thereof and containing dopant, the slab region defining a plane, thereby to form a conductive path across the waveguide, wherein the dopant is bounded on at least two sides by confining layers of oxide, is diffused into the slab region in a direction substantially parallel to said plane, and extends from one of said confining layers of oxide to another of said confining layers of oxide throughout the depth of the slab region in a direction substantially perpendicular to said plane.
An electro-optic device comprising a ridge waveguide formed on a slab region extending to either side thereof and containing dopant, the slab region defining a plane, thereby to form a conductive path across the waveguide, wherein the dopant is bounded on at least two sides by confining layers of oxide, is diffused into the slab region from a side surface of an etched region formed in the slab region, and extends from one of said confining layers of oxide to another of said confining layers of oxide throughout the depth of the slab region in a direction substantially perpendicular to said plane.
An electro-optic device comprising a ridge waveguide formed integrally with a slab region of the same material, the slab region extending to either side of the ridge waveguide and containing a doped region, the slab region defining a plane, thereby to form a conductive path across the waveguide, the doped region being bounded on at least two sides by confining layers of oxide, the confining layers being of a different material to the ridge waveguide, wherein the doped region extends from one of said confining layer of oxide to another of said confining layers of oxide throughout the depth of the slab region in a direction substantially perpendicular to said plane.
A method of forming an electro-optic device comprising the steps of forming a ridge waveguide on a slab surface, the surface defining a plane, etching a region on at least one side of the waveguide and applying a dopant to that etched region thereby to introduce the dopant in a direction substantially parallel to said plane, such that the dopant extends from a first confining layer to a second confining layer throughout the depth of the slab in a direction substantially perpendicular to said plane.
An electro-optic device comprising a ridge waveguide with a slab region on both sides thereof, the slab region defining a plane, dopant being provided in the slab region on both sides of the waveguide to enable an electrical signal to be applied across the waveguide, wherein an etched region is formed in the slab region on both sides of the waveguide and wherein dopant is introduced into the slab region from a side surface of each of the etched regions such that the dopant extends from a first confining layer on one side of the dopant to a second confining layer on another side of the dopant throughout the depth of the slab region in a direction substantially perpendicular to said plane.
Dependencies are inferred from the claim text.