Optical filter

Patent metadata

Field	Value
Publication number	US-10247865-B2
Application number	US-201715657515-A
Country	US
Kind code	B2
Filing date	Jul 24, 2017
Priority date	Jul 24, 2017
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

A bandpass filter may include a set of layers. The set of layers may include a first subset of layers. The first subset of layers may include hydrogenated germanium (Ge:H) with a first refractive index. The set of layers may include a second subset of layers. The second subset of layers may include a material with a second refractive index. The second refractive index may be less than the first refractive index.

First claim

What is claimed is:

1. A bandpass filter, comprising:
a set of layers including:
a first subset of layers,
the first subset of layers comprising hydrogenated germanium (Ge:H) with a first refractive index; and

a second subset of layers,
the second subset of layers comprising a material with a second refractive index,
the second refractive index being less than the first refractive index, and
the material including at least one of:
a silicon dioxide (SiO 2 ) material,
an aluminum oxide (Al 2 O 3 ) material,
a titanium dioxide (TiO 2 ) material,
a niobium pentoxide (Nb 2 O 5 ) material,
a tantalum pentoxide (Ta 2 O 5 ) material, or
a magnesium fluoride (MgF 2 ) material.

2. The bandpass filter of claim 1 , where the first subset of layers are high refractive index layers (H) and the second subset of layers are low refractive index layers (L); and
where the set of layers are arranged in at least one of:
an (H-L) m order,
an (H-L) m -H order,
an (L-H) m order, or
an L-(H-L) m order,
where m is a quantity of alternating H and L layers.

3. The bandpass filter of claim 1 , where the set of layers is configured to pass a threshold portion of light associated with a spectral range of between approximately 1100 nanometers (nm) and 2000 nm.

4. The bandpass filter of claim 1 , where the set of layers is configured to pass a threshold portion of light associated with a spectral range of between approximately 1400 nanometers (nm) and 2000 nm.

5. The bandpass filter of claim 1 , where the set of layers is configured to pass a threshold portion of light associated with a spectral range with a center wavelength of approximately 1550 nanometers.

6. The bandpass filter of claim 1 , where the first refractive index is greater than approximately 3.8 at a wavelength of approximately 1550 nanometers.

7. The bandpass filter of claim 1 , where the first refractive index is approximately 4.2 at a wavelength of approximately 1550 nanometers.

8. The bandpass filter of claim 1 , where the first subset of layers is associated with an extinction coefficient of less than approximately 0.01 at a spectral range centered at approximately 1550 nanometers.

9. The bandpass filter of claim 1 , where the second refractive index is less than 3 at a spectral range of approximately 1100 nanometers (nm) to approximately 2000 nm.

10. The bandpass filter of claim 1 , where a change to a center wavelength of a spectral range is less than 40 nanometers for angles of incidence from 0 degrees to 40 degrees.

11. The bandpass filter of claim 1 , where a change to a center wavelength of a spectral range is less than 30 nanometers for angles of incidence from 0 degrees to 40 degrees.

12. The bandpass filter of claim 1 , where a change to a center wavelength of a spectral range is less than 20 nanometers for angles of incidence from 0 degrees to 30 degrees.

13. The bandpass filter of claim 1 , where a change to a center wavelength of a spectral range is less than 10 nanometers for angles of incidence from 0 degrees to 20 degrees.

14. An optical filter, comprising:
a substrate; and
a set of alternating high refractive index layers and low refractive index layers disposed onto the substrate to filter incident light,
where the optical filter is configured to pass a first portion of the incident light within a spectral range with a center wavelength of approximately 1550 nanometers (nm) and reflect a second portion of incident light not within the spectral range,
the high refractive index layers being hydrogenated germanium (Ge:H), and
the low refractive index layers being silicon dioxide (SiO 2 ).

15. The optical filter of claim 14 , where the high refractive index layers are deposited using a sputtering procedure.

16. The optical filter of claim 14 , where the high refractive index layers are annealed.

17. An optical system, comprising:
an optical filter configured to filter an input optical signal and provide the filtered input optical signal,
the input optical signal including light from a first optical source and light from a second optical source,
the optical filter including a set of dielectric thin film layers,
the set of dielectric thin film layers including:
a first subset of layers of hydrogenated germanium with a first refractive index,
a second subset of layers of a material with a second refractive index less than the first refractive index,

the material including at least one of:
a silicon dioxide (SiO 2 ) material,
an aluminum oxide (Al 2 O 3 ) material,
a titanium dioxide (TiO 2 ) material,
a niobium pentoxide (Nb 2 O 5 ) material,
a tantalum pentoxide (Ta 2 O 5 ) material, or
a magnesium fluoride (MgF 2 ) material, and

the filtered input optical signal including a reduced intensity of light from the second optical source relative to the input optical signal; and

an optical sensor configured to receive the filtered input optical signal and provide an output electrical signal.

18. The optical system of claim 17 , where the optical filter is disposed onto a sensor element array of the optical sensor.

19. The optical system of claim 17 , where the optical filter is separated from a sensor element by free space.

20. The optical system of claim 17 , where the optical filter is associated with a thickness of approximately 5.6 μm.

Assignees

• Viavi Solutions Inc

Inventors

• Switzer Iii James
• Ockenfuss Georg J

Classifications

• G02B6/02395

  Glass optical fibre with a protective coating, e.g. two layer polymer coating deposited directly on a silica cladding surface during fibre manufacture (G02B6/02052, G02B6/02057, G02B6/024, G02B6/032, G02B6/105, G02B6/14 take precedence; coating on fibre gratings G02B6/02104; multilayer core or cladding G02B6/036; reinforcing splice joints G02B6/2558; optical cables, i.e. comprising protective structures external to the protective coating such as a jacket or plural coated optical fibres G02B6/44; coating of glass to obtain optical fibres C03C25/104) · CPC title

• G02B5/0816

  Multilayer mirrors, i.e. having two or more reflecting layers (G02B5/0883, G02B5/0891 take precedence) · CPC title

• G02B6/03616

  Optical fibres characterised both by the number of different refractive index layers around the central core segment, i.e. around the innermost high index core layer, and their relative refractive index difference · CPC title

• G02F2001/0151

  Physics · mapped topic

• G02B6/4483

  Injection or filling devices · CPC title