EP0321087A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Anti-reflection coatings
Assignee: British Telecommunications PLC
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Filing: 1988-11-08
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Granted: —
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Expires: 2008-11-08
Abstract
Abstract Optical devices, e.g. amplifiers, include anti-reflection coatings of hafnium oxide. The coatings are obtained by low temperature deposition in the presence of oxygen. It is important to adjust the degree of oxidation in order to obtain the target refractive index. Slower rates of deposition and oxidation favour stability of performance parameters. The coatings are useful for application to GaInAsP semiconductors.
Inventors
- 👤 David John Elton
- 👤 William John Devlin
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-05 10:42
CPC Classifications
H; H10; H10H; H10H20/00; H10H20/80; H10H20/84; G; G02; G02B; G02B1/00; G02B1/10; G02B1/11; G02B1/113; H01; H01S; H01S5/00; H01S5/02; H01S5/028; H10F; H10F77/00; H10F77/30
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
22 words
An opto-electronic or electro-optic device having an anti-reflection coated facet for the transmission of optical radiation, wherein said coating is hafnium oxide.
Claim 2
Dependent Claim
22 words
An opto-electronic or electro-optic device having an anti-reflection coated facet for the transmission of optical radiation, wherein said coating is hafnium oxide.
Claim 3
Dependent Claim
32 words
A device according to claim 1, wherein said coating is applied to a semiconductor material formed of at least one of Ga and In and at least one of As and P.
Claim 4
Dependent Claim
24 words
A device according to claim 2, wherein said coating is applied to a semiconductor material formed of all of Ga, In, As and P.
Claim 5
Dependent Claim
25 words
A device according to claim 3, wherein the device has an active layer of indium gallium phosphide arsenide located between confining layers of indium phosphide.
Claim 6
Independent Claim
27 words
A device according to any one of the preceding claims, wherein the coating has a refractive index, measured at wavelength 632.8nm, in the range 1.87 to 2.00.
Claim 7
Independent Claim
24 words
A device according to any one of the preceding claims in which the coating has a packing density in the range 0.86 to 0.96.
Claim 8
Independent Claim
20 words
A device according to any one of the preceding claims, wherein the coating has a reflectance of less than 0.5%.
Claim 9
Dependent Claim
32 words
A single pass optical amplifier according to any one of the preceding claims, which includes two coatings as specified, i.e. one coating on the input facet and one on the output facet.
Claim 10
Dependent Claim
31 words
A double pass optical amplifier which has an anti-reflection coating according to any one of claims 1 to 6, on the input/output facet and a mirror coating on the other facet.
Claim 11
Dependent Claim
54 words
A method of depositing a coating as specified in claim 1, which method comprises exposing the facet to be coated to hafnium oxide in the vapour phase and in the presence of an atmosphere of oxygen at a pressure of 10⁻⁴ to 10⁻³mbar and depositing the coating at a rate of less than 2nm/s.
References Cited (Backward Citations)
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