MUX/DEMUX comprising capillary filter block and methods of producing the same

Patent metadata

Field	Value
Publication number	US-10012796-B2
Application number	US-201615388556-A
Country	US
Kind code	B2
Filing date	Dec 22, 2016
Priority date	Dec 28, 2015
Publication date	Jul 3, 2018
Grant date	Jul 3, 2018

Abstract

A multiplexer/demultiplexer is provided comprising a capillary filter block, a capillary adhesive, a signal-routing block, and an index-matching adhesive. The capillary adhesive resides in the capillary interstices of the capillary filter block and the index-matching adhesive forms an optical and mechanical interface between the signal-routing block and the capillary filter block. The layer thickness of the index-matching adhesive accommodates for extra-planar surface irregularities in the bonding face of the signal routing block and extra-planar variations along the proximal ends of the component filter blocks of the capillary filter block. The capillary filter block can be formed from a plurality of component filter blocks by dicing multiple component filter blocks from a filter block substrate, placing the component filter blocks adjacent to one another, and using capillary force to draw adhesive between adjacent sidewalls of component filter blocks.

First claim

What is claimed is:

1. A multiplexer/demultiplexer comprising:
a common port;
a plurality of input/output ports;
a capillary filter block;
a capillary adhesive;
a signal-routing block; and
an index-matching adhesive, wherein
the capillary filter block comprises a plurality of component filter blocks,
each of the component filter blocks of the capillary filter block comprises a proximal end, a distal end, and a pair of capillary side walls extending from the proximal end of the component filter block to the distal end of the component filter block,
each of the component filter blocks of the capillary filter block further comprises a thin-film filter disposed at the distal end of the component filter block,
the component filter blocks are arranged side-by-side comprising respective capillary interstices between adjacent capillary side walls of the component filter blocks,
the capillary adhesive resides in the capillary interstices of the capillary filter block to secure the component filter blocks to each other with the thin-film filters of each component filter block in a common filter plane,
the index-matching adhesive forms an optical and mechanical interface between a bonding face of the signal-routing block and the capillary filter block along the proximal ends of the component filter blocks of the capillary filter block,
a layer thickness of the index-matching adhesive is sufficient to accommodate extra-planar surface irregularities in the bonding face of the signal routing block and extra-planar variations along the proximal ends of the component filter blocks of the capillary filter block,
the capillary adhesive and the index-matching adhesive are temporally discontinuous,
the capillary filter block and the signal-routing block are arranged such that a multiplexed optical signal entering the signal-routing block through the common port can pass through the signal-routing block and the capillary filter block in a back-and-forth progression to successive ones of the thin-film filters for successive wavelength-selective transmission and reflection at the input/output ports, and
the capillary filter block and the signal-routing block are arranged such that demultiplexed optical signals entering the capillary filter block through the input/output ports can pass through the signal-routing block and the capillary filter block in a back-and-forth progression for multiplexing at successive ones of the thin-film filters and multiplexed transmission through the common port.

2. The multiplexer/demultiplexer as claimed in claim 1 wherein the capillary interstices define a width extending substantially orthogonally between adjacent capillary side walls of between about 10 μm and about 100 μm.

3. The multiplexer/demultiplexer as claimed in claim 1 wherein the capillary interstices define a height extending substantially parallel to the capillary side walls of between about 0.3 mm and about 1 mm.

4. The multiplexer/demultiplexer as claimed in claim 1 wherein the capillary interstices define dimensions that enable the capillary adhesive to be drawn into a majority of an interstitial volume of respective ones of the capillary interstices using capillary forces.

5. The multiplexer/demultiplexer as claimed in claim 1 wherein the capillary adhesive does not extend substantially outside the capillary interstices and the index-matching adhesive does not extend substantially into the capillary interstices.

6. The multiplexer/demultiplexer as claimed in claim 1 wherein the multiplexer/demultiplexer comprises a chemical or physical demarcation between the capillary adhesive and the index-matching adhesive.

7. The multiplexer/demultiplexer as claimed in claim 1 wherein the capillary adhesive defines a room temperature viscosity that enables the capillary adhesive to be drawn into a majority of respective interstitial volumes of the capillary interstices under capillary forces.

8. The multiplexer/demultiplexer as claimed in claim 7 wherein the capillary adhesive defines a room temperature viscosity of between about 500 cps and about 15,000 cps.

9. The multiplexer/demultiplexer as claimed in claim 8 wherein the index-matching adhesive defines a room temperature viscosity of between about 100 cps and about 50,000 cps.

10. The multiplexer/demultiplexer as claimed in claim 1 wherein the accommodation of the extra-planar surface irregularities in the bonding face and the extra-planar variations along the proximal ends of the component filter blocks require an index-matching adhesive layer thickness of between about 10 μm and about 200 μm.

11. The multiplexer/demultiplexer as claimed in claim 1 wherein the layer thickness of the index-matching adhesive is between about 10 μm and about 200 μm.

12. The multiplexer/demultiplexer as claimed in claim 1 wherein the extra-planar variations along the proximal ends of the component filter blocks are attributable to dimensional non-uniformities across the component filter blocks, surface irregularities in the proximal ends of the component filter blocks, non-planar portions in the proximal ends of the component filter blocks, or combinations thereof.

13. The multiplexer/demultiplexer as claimed in claim 1 wherein the layer thickness of the index-matching adhesive is at least 1 to 2 times as great as a dimension of a largest of the extra-planar variations along the proximal ends of the component filter block.

14. The multiplexer/demultiplexer as claimed in claim 1 wherein the extra-planar surface irregularities in the bonding face comprise discrete surface features extending out of a bonding plane defined by the bonding face, non-planar portions of the bonding face, or combinations thereof.

15. The multiplexer/demultiplexer as claimed in claim 1 wherein the layer thickness of the index-matching adhesive is at least 1 to 10 times as great as a dimension of a largest of the extra-planar surface irregularities in the bonding face.

16. The multiplexer/demultiplexer as claimed in claim 1 wherein:
the signal-routing block defines a routing block thickness dimension x extending orthogonally between a reflective coating on a first side of the signal-routing block and an interface between the signal-routing block and the component filter blocks on a second side of the signal-routing block, and x is less than about 5.7 mm; and
the plurality of component filter blocks define a component filter block thickness dimension y extending orthogonally between the thin-film filters and the interface between the component filter blocks and the signal-routing block, and y is less than about 2 mm.

17. The multiplexer/demultiplexer as claimed in claim 1 wherein:
the signal-routing block defines a signal-routing block thickness dimension x extending orthogonally between a reflective coating on a first side of the signal-routing block and an interface between the signal-routing block and the component filter blocks on a second side of the signal-routing block;
the plurality of component filter blocks define a filter block thickness dimension y extending orthogonally between the thin-film filters and the interface between the component filter blocks and the signal-routing block; and
the dimensions x and y define a dimensional ratio z, where:

z
=

y
x

and
0.1≤ z≤ 1.7.

18. The multiplexer/demultiplexer as claimed in claim 1 wherein:
the mul

Assignees

• Alliance Fiber Optics Prod Inc

Inventors

• Xiao Qijun
• Gui Dong
• Zhou Andy

Classifications

• H04B10/27

  Arrangements for networking · CPC title

• H04J14/02

  Wavelength-division multiplex systems · CPC title

• G02B6/2938

  for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM · CPC title

• G02B6/29367 Primary

  Zigzag path within a transparent optical block, e.g. filter deposited on an etalon, glass plate, wedge acting as a stable spacer · CPC title

• G02B6/29398

  Temperature insensitivity · CPC title