U.S. Philips Corporation

Uniphase Opto Holdings, Inc.

Leonardus J Hendrix

Johannes C Rijpers

Henricus M De Vrieze

Wilma Van Es-Spiekman

Bastiaan H Verbeek

A diode laser present in an gas or vacuum atmosphere. The semiconductor body of the diode laser comprises two end faces which bound the resonant cavity within which radiation is generated in an active region. The active region forms part of an active layer situated between two cladding layers on a substrate. At least one end face is coated with a covering layer. The covering layer comprises at least two sub-layers of a first dielectricum with a first refractive index and of a second dielectricum with a second refractive index, respectively, and the optical thicknesses and refractive indices of the sub-layers are chosen such that the maximum intensity of the field strength of the generated radiation in the semiconductor body and the covering layer lies outside the end face, and preferably such that the intensity of the field strength of the generated radiation is approximately a minimum adjacent the end face. Preferably, the covering layer comprises two or three sub-layers of dielectric materials such as Al.sub.2 O.sub.3, Si.sub.3 N.sub.4, and SiO.sub.2, on an exit face. A very thin intermediate layer of Si or Al is preferably present between the semiconductor body and the covering layer. The invention also relates to a method of manufacturing such a diode laser.

Semiconductor diode laser and method of manufacturing same

The invention relates to a method of manufacturing a radiation-emitting semiconductor diode (10) whereby a sacrificial layer (1) comprising a polymer is provided on a first side face (11) of a semiconductor body (20) which contains at least one radiation-emitting semiconductor diode (10), a coating (2) is subsequently provided on the first side face (11) and on a second side face (12) of the semiconductor body (20) which encloses an angle with the first side face (11) and which forms an exit face for the radiation to be generated by the diode (10), after which the first side face (11) is divested of the sacrificial layer (1) and of the portion (21) of the coating (2) situated thereon through etching of the sacrificial layer (1). It is possible by such a method, for example, to cover the mirror faces (11, 14) of a laser diode (10) selectively with a reflecting, anti-reflection, or passivating coating (2). A disadvantage of the known method is that laser diodes (10) manufactured thereby are difficult to solder. According to the invention, this disadvantage is obviated in that a protective layer (3) comprising an inorganic material is provided on the sacrificial layer (1) before the provision of the coating (2) in the method. Such a protective layer (3) prevents damage to the sacrificial layer (1), and thus prevents portions of the coating (2), which cannot be removed anymore, from depositing on the first side face (11) which comprises, for example, a metal layer (7). Preferably, the protective layer (3) comprises a metal, for example aluminium. This also prevents the sacrificial layer (1) from becoming badly soluble owing to UV radiation released in a sputter deposition process of the coating (2). Remainders of the sacrificial layer (1) on the metal layer (7), which also result in bad soldering properties, are avoided thereby. (Laser) diodes thus manufactured have a long useful life and are highly suitable for high-power applications.

Method of manufacturing a radiation-emitting semiconductor diode

An optical amplifier with a semiconductor body comprising a layer structure grown on a substrate 1 with an active layer 4 situated between two cladding layers (2, 3) with a strip-shaped amplification region bounded by two end surfaces (7, 8) which form the input and output surfaces of the radiation to be amplified. The active layer comprises a number of quantum well (QW) layers 4A with direct band transition, which are separated by barrier layers 4B of a different semiconductor material. The material, the number, and the thickness of the QW layers 4A and the barrier layers 4B in combination with the length 1 of the amplification region are chosen in such a way that two optical transitions can take place in the active layer 4, maximum amplification occurring at a certain current density through the PN junction for the radiation wavelengths corresponding to these optical transitions, while the end surfaces (7, 8) are provided with an anti-reflection layer 9 which has a reflection coefficient R of at most 0.5% for these two wavelengths. An anti-reflection layer made up of four layers of alternately titanium oxide and aluminum oxide is advantageously used.

Growing community of inventors

Eindhoven, Netherlands

Leonardus J Hendrix