EP0259919A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
DFB laser with anti-reflection layer
Assignee: Koninklijke Philips NV
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Filing: 1987-08-28
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Granted: —
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Expires: 2007-08-28
Abstract
Abstract A semiconductor laser of the distributed feedback (DFB or DBR) type, the laser being bounded in the longitudinal direction by end surfaces (5,6) at right angles to the active region and at least one of these end faces (5) being provided with an anti-reflection layer (8) in order to suppress Fabry-Pérot modes. According to the invention, in order to obtain an optimum effect, an anti-reflection layer of hafnium oxide is used. The invention is used more particularly with great advantage in lasers of the DCPBH (Double Channel Planar Buried Hetero-structure) type.
Inventors
- 👤 Henricus Catharine Johanna Krekels
- 👤 Pieter Ids Kuindersma
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-06 11:06
CPC Classifications
H; H01; H01S; H01S5/00; H01S5/20; H01S5/22; H01S5/227; H01S5/02; H01S5/028; H01S5/10; H01S5/12; H01S5/125; H01S5/2275; H01S5/2277
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
203 words
A semiconductor laser having a semiconductor body comprising a substrate of a first conductivity type and a layer structure disposed thereon having at least a first passive layer of the first conductivity type, a second passive layer of the second opposite conductivity type and an active layer located between the first and the second passive layer and further comprising a pn junction which can produce, at a sufficiently high current intensity in the forward direction, coherent electromagnetic radiation in a strip-shaped active region located within a resonant cavity, the first and second passive layers having a smaller refractive index for the radiation produced and a larger band gap than the active layer and the resonant cavity being formed by periodical variation in the effective refractive index in the longitudinal direction and over at least part of the length of the active region, while the active region is bounded by end surfaces substantially at right angles to the active region and an anti-reflection layer is provided on at least one of said end surfaces and is in direct contact therewith, the second passive layer and the substrate being electrically connected to connection conductors, characterized in that the anti-reflection layer consists of hafnium oxide (HfO₂).
Claim 2
Dependent Claim
203 words
A semiconductor laser having a semiconductor body comprising a substrate of a first conductivity type and a layer structure disposed thereon having at least a first passive layer of the first conductivity type, a second passive layer of the second opposite conductivity type and an active layer located between the first and the second passive layer and further comprising a pn junction which can produce, at a sufficiently high current intensity in the forward direction, coherent electromagnetic radiation in a strip-shaped active region located within a resonant cavity, the first and second passive layers having a smaller refractive index for the radiation produced and a larger band gap than the active layer and the resonant cavity being formed by periodical variation in the effective refractive index in the longitudinal direction and over at least part of the length of the active region, while the active region is bounded by end surfaces substantially at right angles to the active region and an anti-reflection layer is provided on at least one of said end surfaces and is in direct contact therewith, the second passive layer and the substrate being electrically connected to connection conductors, characterized in that the anti-reflection layer consists of hafnium oxide (HfO₂).
Claim 3
Dependent Claim
34 words
A semiconductor laser as claimed in Claim 1, characterized in that the anti-reflection layer has a thickness corresponding to an optical path length of a quarter wavelength for the radiation produced by the laser.
Claim 4
Dependent Claim
23 words
A semiconductor laser as claimed in Claim 1 or 2, characterized in that the anti-reflection layer is provided on both said end surfaces.
Claim 5
Dependent Claim
27 words
A semiconductor laser as claimed in any one of the preceding Claims, characterized in that the laser is of the DCPBH (Double Channel Planar Buried Hetero-structure) type.
Claim 6
Dependent Claim
43 words
A semiconductor laser as claimed in any one of the preceding Claims, characterized in that the substrate consists of n -type indium phosphide (InP) and in that the active layer consists of indium-gallium-arsenic phosphide (In x GA 1-x As y P 1-y ).
References Cited (Backward Citations)
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