1. A fixing device for fixing bones, the fixing device comprising:
a screw element having a threaded shank and a ball segment-shaped head;
a holder comprising a lower portion and an upper portion for receiving two rods and for receiving the ball segment-shaped head of the screw element therebetween, and
a fastener configured to connect together the upper and lower portions of the holder;
wherein each of the lower portion and the upper portion has a first recess for receiving a first rod therebetween and a second recess for receiving a second rod therebetween;
wherein each of the lower portion and the upper portion has a third recess for receiving the ball segment shaped head therebetween;
wherein each of the lower portion and the upper portion are configured to simultaneously fix the ball segment-shaped head of the screw element between the third recesses and the first and second rods between the first and second recesses, respectively, when the upper and lower portions are fastened together by the fastener.
2. The fixing device according to claim 1, wherein the upper portion and the lower portion have identical structure.
3. The fixing device according to claim 1, wherein the lower portion and the upper portion each has a through hole to the third recess for passage of the threaded shank.
4. The fixing device according to claim 1, wherein the first and second recesses comprise cylinder segment-shaped recesses.
5. The fixing device according to claim 1, wherein the third recess of the lower portion is between the first and second recesses of the lower portion.
6. The fixing device according to claim 5, wherein the fastener is a threaded fastener and wherein the lower portion has a threaded bore hole between the third recess and the first recess to receive the fastener.
7. The fixing device according to claim 1, wherein the upper portion has a slot dividing the upper portion into a first half and a second half which are separated by the slot.
8. The fixing device according to claim 1, wherein the upper and lower portions have identical structure and are arranged inversely symmetrically to each other to form the holder:
wherein each third recess comprises a through hole near the center comprising a ball segment-shaped recess for receiving the ball segment-shaped head and for passage of the threaded shank or a tool for turning the screw;
each of the upper and lower portions further comprising two threaded bore holes on opposite sides of the through hole for cooperation with fasteners for connecting the two portions;
wherein each of the upper and lower portions comprises two end portions on opposite sides of the through hole; and a cylinder segment-shaped recess on each of the opposite end portions for receiving a rod.
9. The fixing devices according to claim 1 further comprising a second fixing device connected to the fixing device.
10. The fixing device of claim 1 wherein the fastener is a threaded fastener and wherein each of the upper portion and the lower portion has a threaded bore hole to receive the threaded fastener for fastening the upper and lower portions together.
11. The fixing device of claim 10, wherein the first and second recesses of each of the upper and lower portions is a cylinder segment-shaped recess for receiving the rods.
12. The fixing device of claim 11, wherein the third recess of each of the upper and lower portions is a ball segment-shaped portion for receiving the ball segment-shaped head.
13. The fixing device of claim 1, further comprising a second fastener configured to connect together the upper and lower portions of the holder, wherein the fasteners are threaded fasteners and wherein each of the upper and lower portions has first and second threaded bore holes to receive the fasteners, respectively, for fastening the upper and lower portions together.
14. The fixing device of claim 13, wherein the third recess of each of the upper and lower portions is between the first and second threaded bores.
15. The fixing device of claim 14, wherein the first and second threaded bores of each of the upper and lower portions between the first and second recesses.
16. The fixing device of claim 13, wherein the third recess of each of the upper and lower portions is between the first and second recesses.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. An optical semiconductor device having a buried hetero structure, comprising:
a semi-insulating semiconductor block layer;
a carrier trap layer; and
a clad layer and a contact layer, each of which is formed by selective growth;
the carrier trap layer and the semi-insulating block layer having an etched mesa-structure.
2. A device as claimed in claim 1, wherein:
each of the carrier trap layer and the semi-insulating block layer has an etching depth,
the semi-insulating block layer is formed on a substrate, and
the etching depth reaches the semi-insulating block layer, and does not reach the substrate.
3. A device as claimed in claim 1, wherein:
the semi-insulating block layer comprises a Fe-doped InP.
4. A device as claimed in claim 1, wherein:
the semi-insulating block layer comprises a Ru-doped InP.
5. A device as claimed in claim 1, wherein:
the carrier trap layer comprises a Si-doped InP.
6. A device as claimed in claim 1 wherein:
the carrier trap layer comprises a Se-doped InP.
7. An optical communication module, comprising:
the optical semiconductor device as claimed in claim 1;
an introducing mechanism which introduces an output light beam from the optical semiconductor device to an external;
an inputting unit which supplies the output light beam to the introducing mechanism; and
an electric interface which drives the optical semiconductor device.
8. An optical communication system, comprising:
a communication unit which includes the optical semiconductor device as claimed in claim 1; and
an optical communication unit which includes a receiving unit for receiving an output light beam from the communication unit.
9. A method of manufacturing an optical semiconductor device which has a buried hetero structure and which includes a semi-insulating semiconductor block layer and a carrier trap layer, comprising the steps of:
partially forming a clad layer and a contact layer by selective growth; and
partially etching the carrier trap layer and the semi-insulating block layer after the selective growth of the clad layer and the contact layer.
10. A method as claimed in claim 9, wherein:
the contact layer is selectively etched at a first etching rate while each of the carrier trap layer and the semi-insulating block layer is selectively etched at a second etching rate, the first etching rate being slower than the second etching rate,
wherein, a contact layer portion being formed by the selective growth so as to be used as an etching mask.
11. A method as claimed in claim 9, wherein:
each of the carrier trap layer and the semi-insulating block layer has an etching depth,
the semi-insulating block layer is formed on a substrate, and
the etching depth reaches the semi-insulating block layer, and does not reach the substrate.
12. A method of manufacturing an optical semiconductor device which has a buried hetero structure and which includes a semi-insulating semiconductor block layer and a carrier trap layer, comprising the steps of:
partially etching the carrier trap layer and the semi-insulating block layer before forming the semi-insulating block layer and the carrier trap layer; and
selectively growing a clad layer and a contact layer after the etching.
13. A method as claimed in claim 12, wherein:
each of the carrier trap layer and the semi-insulating block layer has an etching depth,
the semi-insulating block layer is formed on a substrate, and
the etching depth reaches the semi-insulating block layer, and does not reach the substrate.