EP0330457A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical in line filters
Assignee: Matra Marconi Space UK Ltd
•
Filing: 1989-02-22
•
Granted: —
•
Expires: 2009-02-22
Abstract
Abstract An optical in-line filter comprises a first waveguide (10) whose output end is coupled to a second, narrower waveguide (12) such that light from the first waveguide (10) of a predetermined waveband or wavebands only is passed to the second waveguide (12), light of other wavebands emerging elsewhere (53) from the open end of the first waveguide (10).
Inventors
- 👤 Terence Paul Young
- 👤 Ian Richard Croston
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 02:40
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/24; G02B6/26; G02B6/28; G02B6/10; G02B6/12; G02B6/12007; G02B6/122; G02B6/125; G02B6/14; G02B6/2804
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
86 words
An optical in-line filter comprising a first, multi-mode waveguide (10,62) whose output end is coupled to an open-end of a second, narrower waveguide (12,63,64,65), the said coupling and the length of the first waveguide being such that light entering the first waveguide undergoes interference between at least two of its modes causing light of substantially a predetermined wavelength or wavelengths only to be passed to the second waveguide from the first waveguide, light of other wavelengths emerging elsewhere from the output end of the first waveguide.
Claim 2
Dependent Claim
86 words
An optical in-line filter comprising a first, multi-mode waveguide (10,62) whose output end is coupled to an open-end of a second, narrower waveguide (12,63,64,65), the said coupling and the length of the first waveguide being such that light entering the first waveguide undergoes interference between at least two of its modes causing light of substantially a predetermined wavelength or wavelengths only to be passed to the second waveguide from the first waveguide, light of other wavelengths emerging elsewhere from the output end of the first waveguide.
Claim 3
Dependent Claim
22 words
A filter according to claim 1, wherein light entering the first waveguide undergoes interference between its first (fundamental) and third order modes.
Claim 4
Dependent Claim
33 words
A filter according to claim 1 or 2, wherein the second waveguide (12,64) is coupled so as to collect light from a central region of the output end of the first waveguide (10,62).
Claim 5
Dependent Claim
47 words
A filter according to claim 1,2 or 3 comprising a third waveguide (63,65,53) separate from the second waveguide (64,12) coupled at one end to a different region of the output end of the first waveguide (10,62) to collect at least some of the light of other wavelengths.
Claim 6
Dependent Claim
19 words
A filter according to any preceding claim in which the second waveguide (12) is coupled to a detector (55).
Claim 7
Dependent Claim
52 words
A filter according to claim 4, in which the second waveguide (12) is coupled to a detector (55) and in which the third waveguide (53) is coupled to the input of a further optical in-line filter (57) in accordance with any preceding claim, arranged to filter a different waveband or different wavebands.
Claim 8
Dependent Claim
25 words
A filter according to any preceding claim, in which at least the first (10,62) and second waveguides (12,64) are channels of an integrated optical device.
Claim 9
Dependent Claim
42 words
A filter according to claim 7, in which the width of the first waveguide channel (10), is in the range such that the first waveguide supports a symmetric, third mode waveform which is coupled strongly to a corresponding symnmetric, first mode waveform.
Claim 10
Dependent Claim
28 words
A filter according to any preceding claim, comprising means (11,60) for directing an input optical wave into a central region of an input end of the first waveguide.
Claim 11
Dependent Claim
54 words
A filter according to any preceding claim and including a waveguide section (60) arranged at the input end of the first waveguide (62) such that light from the waveguide section is coupled into the first waveguide and wherein the waveguide section is wider over at least some of its length than the first waveguide.
Claim 12
Dependent Claim
15 words
A filter according to claim 10 wherein the waveguide section (60) has smoothly curving bounds.
Claim 13
Dependent Claim
26 words
A filter according to claim 10 or 11 wherein the waveguide section is capable of supporting at least the sixth order mode at its widest part.
Claim 14
Dependent Claim
58 words
A filter according to any preceding claim and including three relatively narrow waveguides (63,64,65) coupled to the output end of the first waveguide (62) and arranged such that light of substantially one predetermined wavelength or wavelengths is coupled into one narrow waveguide (64) and light of other wavelengths is coupled into both of the other narrow waveguides (63,65).
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.