What is claimed is:
1. An optical fiber communications system, comprising:
at least one source of optical energy;
an optical fiber cable including at least one positive dispersion optical fiber coupled to said at least one source, and at least one inverse dispersion optical fiber coupled to the positive dispersion optical fiber,
wherein the inverse dispersion optical fiber includes
a doped core region having an index of refraction n1,
a cladding region having an index of refraction n2,
a trench region between the doped core region and the cladding region and adjacent the doped core region, the trench region having an index of refraction n3,
a first barrier region between the doped core region and the cladding region and adjacent the trench region, the first barrier region having an index of refraction n4, and
a second barrier region between the doped core region and the cladding region and adjacent the first barrier region, the second barrier region having an index of refraction n5,
wherein the inverse dispersion optical fiber has a chromatic dispersion between approximately 48 picosecond(nanometer-kilometer) and 38 picosecond(nanometer-kilometer) at a wavelength of 1550 nanometer (nm),
wherein the optical fiber has a median loss less than or equal to approximately 0.235 decibels (dB) per kilometer (dBkm) at 1550 nm; and
at least one receiver coupled to the inverse dispersion optical fiber for receiving optical energy from the source.
2. The system as recited in claim 1, wherein the inverse dispersion optical fiber has a relative dispersion slope (RDS) that is approximately 0.0030 nm1 at a wavelength of 1550 nm.
3. The system as recited in claim 1, wherein the doped core region, the cladding region, the trench region, the first barrier region and the second barrier region are configured in such a way that approximately 0.709%<(n1n2)n2<1%, approximately 0.358%<(n3n2)n2<0.293%, approximately 0.194%<(n4n2)n2<0.237%, and approximately 0.045%<(n5n2)n2<0.037%, wherein 1(n1n2)n2, 2(n3n2)n2, 3(n4n2)n2 and 4(n5n2)n2
4. The system of claim 3, wherein 1 is approximately 0.788%, 2 is approximately 0.326%, 3 is approximately 0.215%, and 4 is approximately 0.041%.
5. The system as recited in claim 1, wherein the inverse dispersion optical fiber has an effective mode-field area, Aeff, of at least approximately 30 micrometers squared (m2) at a wavelength of 1550 nm.
6. The system as recited in claim 1, wherein the optical fiber cable further comprises a plurality of inverse dispersion fibers spliced together, wherein the splice loss between spliced inverse dispersion fibers is less than or equal to 0.15 dB at a wavelength of approximately 1550 nm.
7. The system as recited in claim 1, wherein the splice loss between the positive dispersion fiber and said at least one inverse dispersion fiber is less than or equal to 0.40 dB at a wavelength of approximately 1550 nm.
8. The system as recited in claim 1, wherein the inverse dispersion optical fiber has a mode-field diameter (MFD) of approximately 6.4 m at a wavelength of 1550 nm.
9. The system as recited in claim 1, wherein the inverse dispersion optical fiber has a chromatic dispersion slope of approximately 0.133 ps nm2 km1 at a wavelength of 1550 nm.
10. The system as recited in claim 1, wherein the radius of the doped core region is approximately 2.415 m, the width of the trench region is approximately 3.090 m, the width of the first barrier region is approximately 3.715 m, and the width of the second barrier region is approximately 1.765 m.
11. An inverse dispersion optical fiber, comprising:
a doped core region having an index of refraction n1;
a cladding region having an index of refraction n2, wherein approximately 0.709%<(n1n2)n2<1%, and wherein 1(n1n2)n2,
a trench region between the doped core region and the cladding region and adjacent the doped core region, the trench region having an index of refraction n3, wherein approximately 0.358%<(n3n2)n2<0.293%, and wherein 2(n3n2)n2;
a first barrier region between the doped core region and the cladding region and adjacent the trench region, the first barrier region having an index of refraction n4, wherein approximately 0.194%<(n4n2)n2<0.237%, and wherein 3(n4n2)n2; and
a second barrier region between the doped core region and the cladding region and adjacent the first barrier region, the second barrier region having an index of refraction n5, wherein approximately 0.045%<(n5n2)n2<0.037%, and wherein 4(n5n2)n2.
12. The inverse dispersion optical fiber of claim 11, wherein 1 is approximately 0.788%, 2 is approximately 0.326%, 3 is approximately 0.215%, and 4 is approximately 0.041%.
13. The inverse dispersion optical fiber of claim 11, wherein the optical fiber has a median loss that is less than or equal to approximately 0.235 decibels per kilometer (dBkm) at a wavelength of 1550 nm.
14. The inverse dispersion optical fiber of claim 11, wherein the optical fiber has a relative dispersion slope (RDS) that is approximately 0.0030 per nanometer (nm1) at a wavelength of 1550 nm.
15. The inverse dispersion optical fiber of claim 11, wherein the optical fiber has an effective mode-field area, Aeff, of at least approximately 30 micrometers2 (m2) at a wavelength of 1550 nm.
16. The inverse dispersion optical fiber of claim 11, wherein the inverse dispersion optical fiber has a mode-field diameter (MFD) of approximately 6.4 m at a wavelength of 1550 nm.
17. The inverse dispersion optical fiber of claim 11, wherein the optical fiber has a chromatic dispersion slope of approximately 0.133 ps nm2 km1 at at a wavelength of 1550 nm.
18. The inverse dispersion optical fiber of claim 11, wherein the radius of the doped core region is approximately 2.415 micrometers (m), the width of the trench region is approximately 3.090 m, the width of the first barrier region is approximately 3.715 m, and the width of the second barrier region is approximately 1.765 m.
19. The inverse dispersion optical fiber of claim 11, wherein the inverse dispersion optical fiber has a chromatic dispersion between approximately 48 picosecond(nanometer-kilometer) and approximately 38 picosecond(nanometer-kilometer) at a wavelength of 1550 nanometer (nm).
20. A method for making an optical fiber, comprising the steps of:
forming a doped core region having an index of refraction n1;
forming a trench region around the doped core region, the trench region having an index of refraction n3;
forming a first barrier region around the trench region, the first barrier having an index of refraction n4;
forming a second barrier region around the first barrier region, the second barrier region having an index of refraction n5; and
forming a cladding region around the second barrier region, the cladding region having an index of refraction n2,
wherein the doped core region, the cladding region, the trench region, the first barrier region and the second barrier region are configured in such a way that approximately 0.709%<(n1n2)n2<1%, approximately 0.358%<(n3n2)n2<0.293%, approximately 0.194%<(n4n2)n2<0.237%, and approximately 0.045%<(n5n2)n2<0.037%, wherein 1(n1n2)n2, 2(n3n2)n2, 3(n4n2)n2 and 4(n5n2)n2
21. The method of claim 20, wherein 1 is approximately 0.788%, 2 is approximately 0.326%, 3 is approximately 0.215%, and 4 is approximately 0.041%.
22. An optical fiber preform, comprising:
a doped core region having an index of refraction n1;
a cladding region having an index of refraction n2;
a trench region between the doped core region and the cladding region and adjacent the doped core region, the trench region having an index of refraction n3;
a first barrier region between the doped core region and the cladding region and adjacent the trench region, the first barrier region having an index of refraction n4; and
a second barrier region between the doped core region and the cladding region and adjacent the first barrier region, the second barrier region having an index of refraction n5,
wherein the doped core region, the cladding region, the trench region, the first barrier region and the second barrier region are configured in such a way that approximately 0.709%<(n1n2)n2<1%, approximately 0.358%<(n3n2)n2<0.293%, approximately 0.194% <(n4n2)n2<0.237%, and approximately 0.045% <(n5n2)n2<0.037%, wherein 1(n1n2)n2, 2(n3n2)n2, 3(n4n2)n2 and 4(n5n2)n2
23. The optical fiber preform of claim 22, wherein 1 is approximately 0.788%, 2 is approximately 0.326%, 3 is approximately 0.215%, and 4 is approximately 0.041%.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A chair-type massage machine comprising:
a seat portion on which a user can sit;
a backrest arranged at the rear of the seat portion so that the backrest can be tilted by a reclining mechanism, the backrest provided with a waist airbag;
a footrest arranged at the front of the seat portion so that the footrest can be swung upwards and downwards by a swinging mechanism; and
a control unit for inflating and deflating the waist airbag toward and away from the waist of the user,
wherein the control unit is configured to control the inflation of the waist airbag in conjunction with the upward swinging movement of the footrest to perform a waist curving operation on the user.
2. The chair-type massage machine of claim 1, wherein the control unit is configured to simultaneously cause the deflation of the waist airbag and the downward swinging movement of the footrest when releasing the waist curving operation.
3. The chair-type massage machine of claim 1, wherein the control unit is configured to bring the backrest into a reclined state in conjunction with at least one of the inflation of the waist airbag and the upward swinging movement of the footrest.
4. The chair-type massage machine of claim 2, wherein the control unit is configured to bring the backrest into a reclined state in conjunction with at least one of the inflation of the waist airbag and the upward swinging movement of the footrest.
5. A chair-type massage machine comprising:
a seat portion on which a user can sit;
a backrest arranged at the rear of the seat portion so that the backrest can be tilted by a reclining mechanism, the backrest provided with a waist airbag; and
a control unit for inflating and deflating the waist airbag toward and away from the waist of the user,
wherein the control unit is configured to control the inflation of the waist airbag in conjunction with the tilting operation of the backrest to perform a waist curving operation on the user.