What is claimed is:
1. A tapered optical fiber bundle, comprising:
a plurality of input fibers formed into a fiber bundle, the fiber bundle being adiabatically tapered, and heavily-fused into an induced cross-sectional shape with minimally deformed cores and no interstitial space between the input fibers.
2. The tapered optical fiber bundle of claim 1, wherein the input fibers are any of multimode, single mode, multiclad and cladding pumped fibers.
3. An optical fiber device, comprising:
a tapered fiber bundle having a plurality of input fibers, adiabatically tapered, and heavily-fused into an induced compact shape with minimally deformed cores and no interstitial space between the input fibers at a cleaved end; and
an output element coupled to the cleaved end.
4. The optical fiber device of claim 3, wherein the output element is another tapered fiber bundle.
5. The optical fiber device of claim 3, wherein the output element is a single optical fiber.
6. The optical fiber device of claim 5, wherein the single optical fiber is a multimode optical fiber.
7. The optical fiber device of claim 6, wherein at least one of the input fibers is terminated to reduce back reflections.
8. The optical fiber device of claim 5, wherein the single optical fiber is a double clad fiber.
9. The optical fiber device of claim 5, wherein the single optical fiber is pre-tapered.
10. The optical fiber device of claim 3, wherein the output element is fusion spliced to the cleaved end.
11. The optical fiber device of claim 9, wherein a spliced junction between the tapered fiber bundle and the output element is post-tapered.
12. The use of the optical fiber device of claim 3 as any one of an optical combiner, an optical splitter, a cladding-pumped fiber laser, and a cladding-pumped optical amplifier.
13. A method of manufacturing an optical fiber device, comprising:
i) positioning a plurality of optical fibers in a predetermined configuration for forming an optimized encircling radius;
(ii) bundling the positioned plurality of optical fibers while controlling the tension applied on individual fibers to result in a fiber bundle with minimized overall diameter;
(iii) heating and pulling the fiber bundle to heavily fuse the fiber bundle in an adiabatically tapered region into an induced shape with no interstitial space between fibers.
14. The method of claim 13, further including twisting the positioned plurality of optical fibers.
15. The method of claim 13, wherein positioning further includes bonding the plurality of optical fibers with an adhesive to secure their positions before fusing and tapering.
16. The method of claim 13, further including cleaving the bundle at the tapered region.
17. The method of claim 16, where the cleaved end of the bundle is reshaped into a desired cross-section by, at least once, fusion splicing the cleaved end to an optical fiber to match its cross-sectional geometry, and re-cleaving the optical fiber bundle.
18. The method of claim 16, further including coupling the cleaved end to an optical system.
19. The method of claim 16, further including fusion splicing the cleaved end to one of a single optical fiber and an output tapered fiber bundle.
20. The method of claim 19, further including pre-tapering of the single optical fiber.
21. The method of claim 19, further including post-tapering of a junction between the tapered fiber bundle and the one of the single optical fiber and the tapered fiber bundle.
22. The method of claim 13, further including at least partial removal of cladding from the plurality of optical fibers.
23. The method of claim 19, further including at least partial removal of cladding from the one of the output optical fiber and the output tapered fiber bundle.
24. The method of claim 19, further including re-coating at least part of a junction between the tapered fiber bundle and the one of the output optical fiber and the output tapered fiber bundle with a coating material.
25. The method of claim 24, wherein the coating material is one of polymer and metallic coatings materials.
26. The method of claim 19, further including heating of the one of the single optical fiber and cladding pumped fiber to diffuse its core to improve the transfer of light from a corresponding singlemode fiber in the input bundle.
27. A star coupler, comprising:
a tapered fiber bundle formed in the midsection of a plurality of fibers, adiabatically tapered, and heavily-fused into an induced compact shape with minimally deformed cores and no interstitial space between the fibers, such that the plurality of fibers form input and output leads on each side of the fused bundle.
28. The star coupler of claim 28, wherein at least one of the input leads is terminated to reduce back reflections.
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 baking tin comprising:
at least one holding tray (2) for foodstuffs comprising:
a bottom wall (4),
a plurality of consecutive side walls (5, 6, 7, 8) extending away from the bottom wall (4) to define a holding cavity,
a plurality of corners (9, 10, 11, 12) each defined by two consecutive side walls;
a supporting structure (3) comprising:
at least one through opening (13) delimited by a plurality of consecutive edges (14, 15, 16, 17) to define a seat for receiving said tray (2) in said supporting structure (3),
wherein:
at least one of said corners (9, 10, 11, 12) of said tray (2) comprises an undercut (18),
said supporting structure (3) comprises at least one connecting portion (19) between two consecutive edges (14, 15) of the opening (13),
said undercut (18) is engaged by said connecting portion (19) to join said tray (2) to said supporting structure (3).
2. A baking tin as claimed in claim 1, wherein said undercut (18) comprises a first shoulder (20) defining a base surface for abutment and engagement of the connecting portion (19) between two consecutive edges of the opening (13) and a second shoulder (21) defining a top surface for retaining said connecting portion (19) in the undercut (18).
3. A baking tin as claimed in claim 1, wherein said connecting portion (19) is an integral part of said supporting structure (3) and extends between end portions (14a, 15b) of two consecutive edges (14, 15) of the opening (13) thereby connecting the two consecutive edges, said supporting structure (3) being flat.
4. A baking tin as claimed in claim 1 wherein said supporting structure (3) and tray (2) are made of paper or thin paperboard material for food use.
5. A baking tin as claimed in claim 1 wherein each corner (9, 10, 11, 12) formed between two consecutive side walls comprises an undercut (18); each undercut (18) being susceptible of engagement in a respective connecting portion (19) between two edges of said opening (13).
6. A baking tin as claimed in claim 1 wherein each side wall (5, 6, 7, 8) comprises a first side (5a, 6a, 7a, 8a) connected to the bottom wall (4) and a second side (5b, 6b, 7b, 8b) opposite to the first side and facing an entry section of the holding cavity of the tray (2); said side walls (5, 6, 7, 8) being of trapezoidal shape and having said second sides (5b, 6b, 7b, 8b) of larger size than the respective first sides (5a, 6a, 7a, 8a) to define a frustoconical shape of the tray (2).
7. A baking tin as claimed in claim 1 wherein said edges (14, 15, 16, 17) of the opening (13) in the supporting structure (3) are in contact with said side walls (5, 6, 7, 8) of the tray (2) following engagement of the connecting portion (19) in the undercut (18).
8. A baking tin as claimed in claim 1 wherein two opposite side walls (5, 7) of said side walls (5, 6, 7, 8) of the tray (2) comprise two flaps (22, 23), two other opposite side walls (6, 8) comprising two tailpieces of one piece construction with said flaps (23) to define a multi-layered structure closed towards the outside in which said flaps (23) are folded over and in contact with the tailpieces in turn folded over, which are positioned in parallel and in contact with said side wall (6; 8).
9. A baking tin as claimed in claim 1 wherein said tray (2) is made up of a single sheet of paper material and is obtained starting from a flat blank (24).
10. A flat blank made of paper or thin paperboard material for food use, to make a holding tray for foodstuffs, comprising:
a central panel (25) to define a bottom wall (4) of the tray (2),
a plurality of side panels (26, 27, 28, 29) peripherally connected to the central panel (25) through respective weakening lines (30, 31, 32, 33) to define a plurality of side walls (5, 6, 7, 8) of the tray (2),
at least one (26) of said side panels (26, 27, 28, 29) comprising:
at least one flap (349 to define a corner (9) of the tray (2) in combination with an adjacent side panel (27),
characterized in that said at least one side panel (26) comprising said flap (34) has:
at least two parallel cuts (36) extending between said side panel (26) and flap (34) to define an undercut (18) in said corner (9).
11. A blank as claimed in claim 10, comprising a first pair of said panels (26, 28) and a second pair of said panels (27, 29) that are symmetric with respect to the central panel (25); each side panel (26, 28) of said first pair respectively comprising two flaps (34) and at least two parallel cuts (36) extending between the side panel (26, 28) and the first one of said two flaps (34) and at least two parallel cuts (36) extending between said side panel (26, 28) and the second one of said two flaps (34) to define four undercuts (18) in as many corners (9, 10, 11, 12).
12. A blank as claimed in claim 11, wherein each pair of said cuts (36) defines a foldable portion (37) designed to jut out towards the inside of the tray (2) to define a reinforcing element for said undercuts (18), or alternatively wherein said cuts (36) are defined by material removal from said side panel (26, 28) and from the second one of said flaps (34) so as to define a hole in said walls.
13. A baking tin comprising:
one holding tray for foodstuff made of paper material comprising:
a bottom wall;
a plurality of consecutive side walls extending away from the bottom wall to define a holding cavity:
a plurality of corners each defined by two consecutive side walls;
a flat supporting structure made of paper material and comprising:
a through opening delimited by a plurality of consecutive edges to define a countershaped seat for receiving said tray;
wherein
said corners of said tray comprises an undercut each;
said supporting structure comprises a connecting portion between two consecutive edges of the opening;
said undercut comprises a first shoulder defining a base surface for abutment and engagement of the connecting portion between two consecutive edges of the opening and a second shoulder defining a top surface for retaining said connecting portion in the undercut.