A method of forming an optical aperture of a vertical cavity surface emitting laser includes the steps of providing a layer stack of semiconductor layers, the semiconductor layers including an intermediate layer comprising a semiconductor material suitable to be oxidized and oxidizing the intermediate layer to an oxidation width so as to form an oxidized outer region and a non-oxidized central region in the intermediate layer. The method also includes removing at least a part of the oxidized outer region so as to form a gap where the oxidized outer region or the part of the oxidized outer region has been removed, depositing an electrically non-conducting material on walls of the gap with a thickness smaller than a thickness of the gap, and filling a remaining void of the gap with a further material.

A method for fabricating a buried heterostructure semiconductor optical amplifier is provided. The method includes a step providing a patterned dielectric layer on a substrate, the patterned dielectric layer having openings to expose uncovered regions of the substrate. The method also includes, in a single metal organic chemical vapour deposition (MOCVD) run: etching the uncovered regions of the substrate to form angles at corresponding edges thereof and diffusing a p-dopant in the substrate to obtain a p-dopant distribution in a portion of the substrate; etching a portion of the p-dopant thereby defining a recess in the substrate and growing a n-blocking layer in the recess; sequentially growing, over a portion of the n-blocking layer, an active region, a p-overclad, a p-contact, and a p-metal contact; and growing a n-metal contact on a backside of the substrate. The single MOCVD run combines selective area growth, p-dopant diffusion and etching techniques.

A method for fabricating a buried heterostructure semiconductor optical amplifier is provided. The method includes a step providing a patterned dielectric layer on a substrate, the patterned dielectric layer having openings to expose uncovered regions of the substrate. The method also includes, in a single metal organic chemical vapour deposition (MOCVD) run: etching the uncovered regions of the substrate to form angles at corresponding edges thereof and diffusing a p-dopant in the substrate to obtain a p-dopant distribution in a portion of the substrate; etching a portion of the p-dopant thereby defining a recess in the substrate and growing a n-blocking layer in the recess; sequentially growing, over a portion of the n-blocking layer, an active region, a p-overclad, a p-contact, and a p-metal contact; and growing a n-metal contact on a backside of the substrate. The single MOCVD run combines selective area growth, p-dopant diffusion and etching techniques.

A first burying layer burying a side of a first ridge structure is formed by selective growth using a first selective growth mask and a third selective growth mask. The first burying layer is formed by regrowth from a surface of a second semiconductor layer on a side of the first ridge structure. At the same time, by selective growth using a second selective growth mask and a fourth selective growth mask, a second burying layer burying a side of a second ridge structure is formed. The second burying layer is formed by regrowth from a surface of a fourth semiconductor layer on a side of the second ridge structure.

Example vertical cavity surface emitting lasers (VCSELs) include a mesa structure disposed on a substrate, the mesa structure including a first reflector, a second reflector defining at least one diameter, and an active cavity material structure disposed between the first and second reflectors; and a second contact layer disposed at least in part on top of the mesa structure and defining a physical emission aperture having a physical emission aperture diameter. The ratio of the physical emission aperture diameter to the at least one diameter is greater than or approximately 0.172 and/or the ratio of the physical emission aperture diameter to the at least one diameter is less than or approximately 0.36. An example VCSEL includes a substrate; a buffer layer disposed on a portion of the substrate; and an emission structure disposed on the buffer layer.

A semiconductor laser device includes a laser section and a modulator section. The laser section has: a first mesa stripe which is formed on a semiconductor substrate; semi-insulative burying layers which are placed to abut on both side surfaces of the first mesa stripe and are formed on the semiconductor substrate; n-type burying layers formed on respective surfaces of the semi-insulative burying layers; and a p-type cladding layer which covers surfaces of the n-type burying layers and the first mesa stripe. The modulator section has: a second mesa stripe which is formed on the semiconductor substrate; semi-insulative burying layers which are placed to abut on both side surfaces of the second mesa stripe and are formed on the semiconductor substrate; and a p-type cladding layer which covers surfaces of the semi-insulative burying layers and the second mesa stripe.

A semiconductor laser device includes a laser section and a modulator section. The laser section has: a first mesa stripe which is formed on a semiconductor substrate; semi-insulative burying layers which are placed to abut on both side surfaces of the first mesa stripe and are formed on the semiconductor substrate; n-type burying layers formed on respective surfaces of the semi-insulative burying layers; and a p-type cladding layer which covers surfaces of the n-type burying layers and the first mesa stripe. The modulator section has: a second mesa stripe which is formed on the semiconductor substrate; semi-insulative burying layers which are placed to abut on both side surfaces of the second mesa stripe and are formed on the semiconductor substrate; and a p-type cladding layer which covers surfaces of the semi-insulative burying layers and the second mesa stripe.

A method for fabricating a semiconductor device on a semiconductor substrate, wherein the semiconductor device is adapted to provide target lasing properties, the method includes creating, a mask layer over the semiconductor substrate, the mask layer having at least one opening to expose a region of the semiconductor substrate, etching using a first etching process the exposed region, utilizing inductively coupled plasma with preselected first set of parameters to obtain a baseline mesa profile, the baseline mesa profile having a baseline mesa angle, re-etching using a second etching process the etched region, utilizing inductively coupled plasma with preselected second set of parameters, to alter the baseline mesa profile to obtain a requisite mesa profile having a requisite mesa angle defined by the target lasing properties and the requisite mesa angle being different from the baseline mesa angle, removing the mask layer and defining a p-n junction for the semiconductor substrate.

A semiconductor optical amplifier integrated laser includes a semiconductor laser oscillator portion that oscillates laser light having a wavelength included in a gain band and a semiconductor optical amplifier portion that amplifies laser light output from the semiconductor laser oscillator portion. The semiconductor laser oscillator portion and the semiconductor optical amplifier portion have one common p-i-n structure, the common p-i-n structure includes an active layer, a cladding layer provided apart from the active layer, and a common functional layer formed in the cladding layer, and the common functional layer includes a first portion that reflects light having a wavelength within the gain band in the semiconductor laser oscillator portion and a second portion that transmits light having a wavelength within the gain band in the semiconductor optical amplifier portion.

A semiconductor optical amplifier integrated laser includes a semiconductor laser oscillator portion that oscillates laser light having a wavelength included in a gain band and a semiconductor optical amplifier portion that amplifies laser light output from the semiconductor laser oscillator portion. The semiconductor laser oscillator portion and the semiconductor optical amplifier portion have one common p-i-n structure, the common p-i-n structure includes an active layer, a cladding layer provided apart from the active layer, and a common functional layer formed in the cladding layer, and the common functional layer includes a first portion that reflects light having a wavelength within the gain band in the semiconductor laser oscillator portion and a second portion that transmits light having a wavelength within the gain band in the semiconductor optical amplifier portion.