Optical waveguides – With optical coupler – With alignment device
Reexamination Certificate
2002-03-29
2004-04-27
Palmer, Phan T. H. (Department: 2874)
Optical waveguides
With optical coupler
With alignment device
C385S049000, C385S088000
Reexamination Certificate
active
06728450
ABSTRACT:
FIELD OF INVENTION
The present invention relates to the alignment and optical coupling of the end of an array of optical fibres, such as in ribbon fibre, with waveguides in an optical device, such as an active semiconductor optical device or a passive device.
DISCUSSION OF RELATED ART
Optical fibres are commonly used to interconnect optical devices of various forms, including passive waveguide structures in silica and silicon and active semiconductor devices. Attaching optical fibres to optical devices is a technical challenge, particularly when attaching an array of optical fibres, for example in the form of ribbon fibre.
A well known way of attaching ribbon fibre to a passive, multi-channel optical device, for example an arrayed waveguide grating (AWG), involves mounting the end of the ribbon fibre in a fibre block assembly.
FIG. 1
is an end view of a known form of fibre block assembly
1
comprising two blocks
2
bonded together. An array of fibres
3
are mounted between the two blocks
2
in arrays of v-grooves
4
formed in the opposed bonded surfaces
5
of the blocks
2
. The fibre block assembly
1
serves to fix the relative positions of the fibres
3
in the array to a tolerance of, say, around ±0.5 &mgr;m. The end surface of the fibre block assembly
1
is usually polished to an optical surface, either at normal incidence to the optical axes of the fibres or at an angle, if required.
A known way of using the fibre block assembly
1
of
FIG. 1
to couple the optical fibres
3
to a passive optical device such as an AWG is known as “butt coupling”.
FIG. 2
is a side view illustrating the fibre block assembly
1
butt coupled to a passive optical device
6
in which there are waveguides
7
. The polished end surface
8
of the fibre block assembly
1
and the polished surface
9
of the optical device
6
are brought into contact, or close proximity, commonly with a thin layer of optically clear adhesive
10
at the interface between the fibre block assembly
1
and the optical device
6
. Prior to curing of the adhesive
10
, the fibre block assembly
1
and the optical device
6
may be relatively aligned in the directions perpendicular to the optical fibres
3
, that is in the directions up and down in FIG.
2
and into and out of the paper. However, the alignment in the direction in which the fibres
3
extend is fixed and may not be adjusted.
Butt coupling is unsuitable when it is important to avoid physical contact between the optical fibre and the optical device. This is the case, for example, with many active optical devices, such as those made of a semiconductor such as indium phosphide. Contact is also undesirable for optical devices having a fragile thin film coat.
SUMMARY OF INVENTION
The purpose of the present invention is to provide for alignment of an array of optical fibres with an optical device which allows alignment in a direction perpendicular to the optical axes of the optical fibres to be achieved more easily and/or which allows adjustment of the alignment along the direction in which the fibres extend.
According to a first aspect of the present invention, there is provided a method of aligning the end of an array of optical fibres with waveguides in an optical device, comprising: mounting the end of the array of optical fibres in a fibre block assembly comprising at least a first block, the first block having an array of grooves in a grooved surface of the block, the optical fibres being mounted in the grooves, the fibre block assembly further having at least one guide surface on the first block on the same side as the grooved surface at a predetermined level with respect to the axes of the array of optical fibres; supporting the optical device on a support surface of a bench, which bench has at least one guide surface extending from the support surface, by the surface of the optical device proximate to the waveguides; aligning the end of an array of optical fibres with the waveguides in the optical device by moving the fibre block assembly with the at least one guide surface of the first block in contact with the at least one guide surface of the bench; and fixing the fibre block assembly to the bench after said aligning of the end of the array of optical fibres with the waveguides in the optical device.
According to a second aspect of the present invention, there is provided a method of aligning the end of an array of optical fibres with waveguides in an optical device, comprising: mounting the end of the array of optical fibres in a fibre block assembly comprising a first block having an array of grooves in a grooved surface of the first block and a second block fixed to the first block with a surface having no grooves facing the grooved surface of the first block and with the fibres mounted between the blocks in the grooves, the fibre block assembly further having at least one guide surface on the second block on the same side as said surface facing the grooved surface of the first block at a predetermined level with respect to the axes of the array of optical fibres; supporting the optical device on a support surface of a bench, which bench has at least one guide surface extending from the support surface, by the surface of the optical device proximate to the waveguides; aligning the end of an array of optical fibres with the waveguides in the optical device by moving the fibre block assembly with the at least one guide surface of the first block in contact with the at least one guide surface of the bench; and fixing the fibre block assembly to the bench after said aligning of the end of the array of optical fibres with the waveguides in the optical device.
According to a third aspect of the invention, there is provided a coupling assembly optically coupling an array of fibres to an optical device, comprising: the optical device having a plurality of waveguides and having a surface proximate to the waveguides at a predetermined level with respect to the axes of the waveguides; a fibre block assembly mounting the end of the array of optical fibres, the fibre block assembly comprising at least a first block, the first block having a grooved surface defining an array of grooves, the optical fibres being mounted in the grooves, the fibre block assembly further having at least one guide surface on the first block on the same side as the grooved surface at a predetermined level with respect to the axes of the array of optical fibres; and a bench having a support surface on which the optical device is fixed by the surface of the optical device proximate to the waveguides, and at least one guide surface extending from the support surface, at a predetermined level with respect to the support surface, the at least one guide surface of the bench having the fibre block assembly fixed thereon by the at least one guide surface of the fibre block assembly, with the array of optical fibres aligned with the plurality of waveguides of the optical device.
According to a fourth aspect of the invention, there is provided a coupling assembly optically coupling an array of fibres to an optical device, comprising: the optical device having a plurality of waveguides and having a surface proximate the waveguides at a predetermined level with respect to the axes of the waveguides; a fibre block assembly mounting the end of the array of optical fibres, the fibre block assembly comprising at least a first block having a grooved surface defining an array of grooves and a second block fixed to the first block with a surface having no grooves facing the grooved surface of the first block and with the optical fibres mounted between the blocks in the grooves, the fibre block assembly further having at least one guide surface on the same side as said surface facing the grooved surface of the first block at a predetermined level with respect to the axes of the array of optical fibres; and a bench having a support surface on which the optical device is fixed by the surface of the optical device proximate to the waveguides, and at least one guide surface extending
Fasham Stephen James
Tombling Craig
Doan Jennifer
Glenn Michael A.
Glenn Patent Group
Kamelian Limited, A Body Corporate
Palmer Phan T. H.
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