US 3,993,963 A · Heterostructure devices, a light guiding layer having contiguous zones of different thickness and bandgap and method of making same

Abstract

Described is a double heterostructure (DH) junction laser in which the intermediate layer in which light is guided is composed of an active and a passive zone which are disposed in tandem along the direction of light propagation. The active zone is thin and has a relatively narrow bandgap, and the passive zone is thicker and has a wider bandgap. The transition in thickness and bandgap between zones is relatively gradual. Also described is a monolithic integrated circuit including a DH laser and a DH modulator which have such an intermediate layer in common. In addition, described is an LPE growth technique for fabricating the intermediate layer in which two solutions, used to grow simultaneously zones of different composition, are placed on opposite sides of a partition which bifurcates one of the wells of the growth apparatus. The passive zone grows under the partition. In order to reduce mixing between the solutions, a pair of saturating seeds, separated by a divider which is aligned with the partition, are used to bring the bottoms of the two solutions to saturation.

Claims20

Dependent claims

A double heterostructure device comprising first and second wide bandgap layers, and a third narrower bandgap layer intermediate to and contiguous with said first and second layers, said third layer being transparent to optical radiation passing therethrough, CHARACTERIZED IN THAT said third layer includes a narrow bandgap first zone and at least one relatively thicker wider bandgap transition zone in tandem therewith along the direction of radiation transmission.

An integrated optical circuit comprising a first wide bandgap layer, a second wide bandgap layer having a conductivity type opposite to that of said first layer;

means defining at least two electrically isolated segments of said second layer, a third layer intermediate to and contiguous with said first and second layers, said third layer including at least two narrow bandgap active zones and at least three relatively wider bandgap passive zones, said third layer being transparent to optical radiation propagating therein,
a pair of spaced parallel surfaces perpendicular to the direction of propagation of said radiation,
one of said passive zones separating said active zones from one another, and the other of said passive zones separating each of said active zones from separate ones of said surfaces,
each of said electrically isolated segments of said second layer overlaying a separate one of said active zones,
said first layer, one of said segment and its underlying active zone forming a double heterostructure junction laser, and said first layer, the other of said segments and the other of said active zones forming an intracavity double heterostructure junction modulator.

2 more elements

A liquid phase epitaxy method of fabricating a layer having a first zone of one material composition, a second zone of another material composition and a transition zone which is thicker than said first and second zones and which has a material composition and thickness which grades from said first zone to said second zone,

said method being carried out in an apparatus which includes a solution holder having at least one well for carrying a source solution and a seed holder having a recess for carrying a growth seed, said solution and seed holders being movable relative to one another in order to bring said solution and said seed into contact with one another, said apparatus being placed in a furnace, heated to an elevated temperature, and controllably cooled to effect growth, said method being CHARACTERIZED BY the steps of:
a. partitioning said at least one well by means of a thin partition which bifurcates said well into first and second wells;
b. placing a first source solution in said first well;
c. placing a second source solution in said second well;
and
d. bringing said solutions and said seed into contact with one another so that said first zone is grown from said first solution, said second zone is grown from said second solution, and said transition zone is grown beneath said partition.

3 more elements

Dependencies are inferred from the claim text.

Heterostructure devices, a light guiding layer having contiguous zones of different thickness and bandgap and method of making same

Life of this patent

Heterostructure devices, a light guiding layer having contiguous zones of different thickness and bandgap and method of making same

Life of this patent

Abstract

Claims20