THIN FILM INTERLEAVER

• US 20070223860A1
• Filed: 05/24/2007
• Published: 09/27/2007
• Est. Priority Date: 10/31/2002
• Status: Active Grant

• Current Assignee: II-VI Delaware, Inc. (Coherent Corp.)
• Original Assignee: Finisar Corporation (II-VI Incorporated)
• Inventors: Zhang, Yin, Zhang, Kevin, Xie, Ping, Wang, Steve, Zhong, Johnny
• Granted Patent: US 7,561,766 B2
• Time in Patent Office: Days
• US Class Current: 385/18
• CPC Class Codes: G02B 6/2937 In line lens-filtering-lens devices, i.e. elements arranged along a line and mountable in a cylindrical package for compactness, e.g. 3- port device with GRIN lenses sandwiching a single filter operating at normal incidence in a tubular package
• CPC Class Codes: G02B 6/29386 Interleaving or deinterleaving, i.e. separating or mixing subsets of optical signals, e.g. combining even and odd channels into a single optical signal
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0307 Multiplexers; Demultiplexers

Abstract

A thin film interleaver device is disclosed. The thin film interleaver includes thin film optics. The thin film(s) are formed such that they reflect one group of wavelengths while allowing a second group of wavelengths to pass through the thin film(s). The thin film(s) exhibit a flat top frequency response across the channel bandwidths of the multiplexed signal for which the thin film filter is designed such that the thin film interleaver is less sensitive to wavelength drift and temperature variations.

Claims

1. A demultiplexer for use in fiber-optic CWDM applications, the demultiplexer comprising:

a first stage that comprises a thin film interleaver, the thin film interleaver comprising a thin film portion being formed to exhibit a flat top frequency response, wherein the thin film portion passes a first group of channels to pass through the thin film portion while reflecting a second group of channels, each channel of the first group of channels being adjacent to a channel in the second group of channels; and

at least one subsequent stage that includes at least two interleavers for receiving the first and second group of channels.

2. The demultiplexer of claim 1, the thin film interleaver comprising a thin film portion being formed to exhibit a wide frequency response without increasing cross-talk of adjacent channels.

3. The demultiplexer of claim 1, the at least two interleavers being fused fiber interleavers.

4. The demultiplexer of claim 1, the at least two interleavers being thin film interleavers.

5. The demultiplexer of claim 1, the thin film portion further comprising a plurality of cavities wherein each of the plurality of cavities comprises:

a plurality of thin film layers; and

a spacer.

6. The demultiplexer of claim 5, the thin film portion comprising 4 to 6 cavities.

7. The demultiplexer of claim 5, each of the plurality of cavities comprising 72 to 74 thin film layers.

8. The demultiplexer of claim 5, each thin film being about ¼

of a median wavelength, the median wavelength being the median of the first and second group of channels.

9. The demultiplexer of claim 5, wherein the thin film interleaver is configured to maintain low loss of a signal when small changes in a channel are experienced while maintaining separation between channels.

10. A method of manufacturing a thin film interleaver for use in fiber-optic CWDM multiplexing and demultiplexing the method comprising:

forming a thin film portion on a dual fiber collimator having an input fiber and a reflection fiber, the thin film portion being formed to;

exhibit a flat top frequency response; and

separate channels input on the input fiber by allowing a first group of channels to pass through the thin film portion while reflecting a second group of channels into the reflection fiber each of the first group of channels being adjacent to a channel in the second group of channels.

11. The method of claim 10, wherein forming comprises depositing the thin film portion on the dual fiber collimator by chemical deposition.

12. The method of claim 10, wherein forming comprises depositing the thin film portion on the dual fiber collimator by vapor deposition.

13. The method of claim 10, wherein forming comprises growing the thin film portion on the dual fiber collimator.

14. The method of claim 10, further comprising arranging a single fiber collimator to collimate the first group of channels into an output fiber attached to the single fiber collimator.