Optical waveguides – Integrated optical circuit
Reexamination Certificate
2001-11-21
2003-06-10
Juba, Jr., John (Department: 2872)
Optical waveguides
Integrated optical circuit
C385S052000, C438S029000, C438S069000, C372S046012
Reexamination Certificate
active
06577781
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an optical integrated circuit device, having a protrusion, a fabrication method of the same and a module of an optical communication transmission and receiving apparatus using the same, and in particular to an optical integrated circuit device having a protrusion, a fabrication method of same and a module of an optical communication transmission and receiving apparatus using the same which are capable of easily aligning the position of an optical integrated circuit device and optical fiber when assembling an optical communication transmission and receiving apparatus module, obtaining a short position aligning time and preventing a crack phenomenon at a corner portion of an optical integrated circuit device.
DESCRIPTION OF THE BACKGROUND ART
Generally, in order to align a light source (an optical integrated circuit device like a laser diode chip and a photo diode chip) of an optical communication transmission and receiving apparatus module capable of converting an electrical signal into an optical signal or an optical signal into an electrical signal and an optical fiber, an active alignment method and a passive alignment method are used.
The active alignment method requires a long time for aligning a laser diode and an optical fiber for thereby decreasing a mass production. In addition, the active alignment method needs many parts, so that it is impossible to implement a low cost product.
Therefore, the passive alignment method in which a current is not applied to a laser diode, and a laser diode and an optical fiber are directly coupled is increasingly used.
FIG. 1A
 is a disassembled perspective view illustrating an optical communication transmission and receiving apparatus module for explaining a conventional active alignment method with respect to an optical integrated circuit device and an optical fiber.
As shown therein, the optical communication transmission and receiving apparatus module includes a mounting apparatus 
100
 for mounting an optical integrated circuit device, an optical fiber, etc. an optical fiber 
110
 installed in a V-shaped longitudinal groove 
101
 formed on an upper portion of the mounting apparatus 
100
, and an optical integrated circuit device (here, a laser diode) installed at an end portion of the optical fiber 
110
. At this time, a laser diode chip 
120
 is aligned and attached on an upper portion of the mounting apparatus 
100
 in such a manner that an active layer 
121
 which is a light emission layer of the laser diode chip 
120
 is positioned at the center of the optical fiber.
In order to implement an accurate alignment, a rotation adjusting mark 
103
, an optical axis adjusting mark 
105
, etc. are formed on an upper surface of the mounting apparatus 
100
. A position adjusting mark 
123
 is formed on the laser diode 
120
. 
FIG. 1A
 is a view of a method for checking whether the positions of the above marks are accurately aligned using an infrared ray camera. The optical fiber 
110
 and the active layer 
121
 of the laser diode chip 
120
 are matched in the above method.
FIG. 1B
 is a disassembled perspective view of a conventional communication transmission and receiving apparatus module for explaining another example of a position alignment method with respect to an optical integrated circuit device and an optical fiber.
As shown therein, a V-shaped groove 
151
 is formed on an upper surface of the mounting apparatus 
150
. An optical fiber 
160
 is installed on an upper portion of the V-shaped groove 
151
. A concave portion 
152
 is formed at an end of the V-shaped groove 
151
 for mounting the optical integrated circuit device 
170
 therein. A convex portion 
171
 corresponding to the concave portion 
152
 is formed on the surface of the optical integrated circuit device 
170
. The convex portion 
171
 of the optical integrated circuit device 
170
 is inserted into the concave portion 
152
 of the mounting apparatus 
150
, so that the optical fiber 
160
 and the active layer 
172
 of the optical integrate circuit device 
170
 are matched.
However, the above-described conventional position alignment method has the following disadvantages.
The method of 
FIG. 1A
 has an advantage in that the number of parts is decreased for aligning the optical integrated circuit device and the optical fiber. However, since an expensive flip chip bonder which requires an accurate resolution is used, the installation cost of the equipment is high. In addition, the above method is not better than an active alignment method in a view of the process time. The method of 
FIG. 1B
 will be explained with reference to 
FIGS. 2A and 2B
. 
FIGS. 2A and 2B
 are vertical cross-sectional views taken along line IIa—IIa after mounting the optical integrated circuit device 
170
 of 
FIG. 1B
 on the mounting apparatus 
150
.
FIG. 2A
 is a view illustrating a convex portion 
171
 formed on an upper surface of the conventional optical integrated circuit device 
170
 in which a lateral surface 
172
a 
has a vertical profile. 
FIG. 2B
 is a view illustrating a convex portion of the conventional optical integrated circuit device 
170
 in which a lateral surface 
172
b 
has a reverse taper.
As shown in 
FIGS. 2A and 2B
, the size L1 of the concave portion of the mounting apparatus 
150
 is larger than the size L2 of the convex portion 
171
 of the optical integrated circuit device 
170
. Therefore, as shown in 
FIGS. 2A and 2B
, the convex portion 
171
 is inserted into the convex portion 
152
 of the mounting apparatus 
150
. The optical integrated circuit device 
150
 is horizontally moved so that the lateral surfaces 
152
a 
and 
152
b 
of the concave portion 
152
 and the lateral surfaces 
171
a 
and 
171
b 
of the convex portion 
171
 closely contact each other.
At this time, in the case of the convex portion 
171
 having a nearly perpendicular lateral wall profile, when inserting the convex portion 
171
 into the concave portion 
152
, an end portion A of the convex 
171
 collides with an upper portion of the mounting apparatus 
150
, so that the end portion A of the same may be cracked.
In the case that the convex portion 
171
 having a reverse taper lateral wall profile, an end portion B of the convex portion 
171
 may collide with a lateral wall of the concave portion 
150
 of the mounting apparatus, so that the end portion B of the same is cracked. Therefore, a certain defect may occur in the optical integrated circuit device due to the cracks. In addition, a matching property of an alignment between the optical fiber and the optical integrated circuit device may be decreased due to the reverse taper lateral wall profile.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide an optical integrated circuit device and a fabrication method of the same which are capable of easily aligning the position of an optical integrated circuit device and optical fiber when assembling an optical communication transmission and receiving apparatus module, obtaining a short position aligning time and preventing a crack phenomenon at a corner portion of an optical integrated circuit device.
To achieve the above objects, there is provided an optical integrated circuit device comprising a semiconductor substrate, a convex portion formed on an upper surface of the semiconductor substrate and having a taper shape lateral surface, a protection film formed on a lateral wall surface of the convex portion, a first electrode formed on an upper surface of the convex portion, and a second electrode formed on an upper surface of the semiconductor substrate, wherein the convex portion is formed of a first current disconnection layer, a second disconnection layer and a clad layer.
A gradient of the lateral wall surface of the convex portion is 10
~
70° in a direction perpendicular from the surface of the semiconductor substrate.
The protection film is formed of a silicon film or a silicon nitride film.
To achieve the above object, there is provided an optical integrated circuit device fabrication me
Boutsikaris Leo
Iljin Corporation
Jr. John Juba
Roth & Goldman, P.A.
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