A semiconductor laser element includes: a semiconductor substrate; a semiconductor laminate; a first electrode in which a ridge portion of the semiconductor laminate is embedded; and a second electrode. A first region of a side surface of the first electrode is separated from a first end surface in such a manner to extend away from the first end surface as the first region extends away from the ridge portion to both sides. A shortest distance between a first side surface and the first region is smaller than each of a shortest distance between a third side surface and a third region and a shortest distance between a fourth side surface and a fourth region. The first region does not include a corner in a range satisfying D.sub.1 ≤ S.sub.1 and D.sub.1 ≤ S.sub.2.

The embodiment relates to a light-emitting device in which a positional relationship between a modified refractive index region's gravity-center position and the associated lattice point differs from a conventional device, and a production method. In this device, a stacked body including a light-emitting portion and a phase modulation layer optically coupled to the light-emitting portion is on a substrate. The phase modulation layer includes a base layer and plural modified refractive index regions in the base layer. Each modified refractive index region's gravity-center position locates on a virtual straight line passing through a corresponding reference lattice point among lattice points of a virtual square lattice on the base layer's design plane. A distance between the reference lattice point and the modified refractive index region's gravity center along the virtual straight line is individually set such that this device outputs light forming an optical image.

Building blocks are provided for on-chip chemical sensors and other highly-compact photonic integrated circuits combining interband or quantum cascade lasers and detectors with passive waveguides and other components integrated on a III-V or silicon. A MWIR or LWIR laser source is evanescently coupled into a passive extended or resonant-cavity waveguide that provides evanescent coupling to a sample gas (or liquid) for spectroscopic chemical sensing. In the case of an ICL, the uppermost layer of this passive waveguide has a relatively high index of refraction that enables it to form the core of the waveguide, while the ambient air, consisting of the sample gas, functions as the top cladding layer. A fraction of the propagating light beam is absorbed by the sample gas if it contains a chemical species having a fingerprint absorption feature within the spectral linewidth of the laser emission.

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 surface-emitting semiconductor laser includes a substrate, a first electrode provided in contact with the substrate, a first light reflection layer provided over the substrate, a second light reflection layer provided over the substrate, an active layer provided between the second light reflection layer and the first light reflection layer, a current confining layer that is provided between the active layer and the second light reflection layer and includes a current injection region, a second electrode provided over the substrate, with the second light reflection layer being interposed between the second electrode and the substrate, and a contact layer that is provided between the second electrode and the second light reflection layer and includes a contact region that is in contact with the second electrode, in which the contact region has a smaller area than an area of the current injection region.

A dual output laser diode may include first and second end facets and an active section. The first and second end facets have low reflectivity. The active section is positioned between the first end facet and the second end facet. The active section is configured to generate light that propagates toward each of the first and second end facets. The first end facet is configured to transmit a majority of the light that reaches the first end facet through the first end facet. The second end facet is configured to transmit a majority of the light that reaches the second end facet through the second end facet.

A quantum cascade laser element includes: a semiconductor substrate; a semiconductor laminate having a first end surface and a second end surface; a first electrode; a second electrode; and an anti-reflection film formed on the first end surface. The semiconductor laminate is configured to oscillate laser light having a center wavelength of 7.5 μm or more. The anti-reflection film includes an insulating film being a CeO.sub.2 film formed on the first end surface, a first refractive index film being a YF.sub.3 film or a CeF.sub.3 film disposed on a side opposite the first end surface with respect to the insulating film, and a second refractive index film formed on the first refractive index film on a side opposite the first end surface with respect to the first refractive index film and having a refractive index of larger than 1.8.

A quantum-cascade laser element includes: a semiconductor substrate; a semiconductor mesa formed on the semiconductor substrate to include an active layer having a quantum-cascade structure and to extend along a light waveguide direction; an embedding layer formed to interpose the semiconductor mesa along a width direction of the semiconductor substrate; a cladding layer formed over the semiconductor mesa and over the embedding layer; and a metal layer formed on the cladding layer. A pair of groove portions extending along the light waveguide direction are formed in a surface on an opposite side of the cladding layer from the semiconductor substrate. The pair of groove portions are disposed in two respective outer regions when the cladding layer is equally divided into four regions in the width direction of the semiconductor substrate. The metal layer enters the pair of groove portions.

According to embodiments, a semiconductor laser comprises a semiconductor layer stack, which comprises an active zone for generating radiation. The semiconductor laser also comprises a first resonator mirror, a second resonator mirror, and an optical resonator, which is arranged between the first and second resonator mirrors and extends in a direction parallel to a main surface of the semiconductor layer stack. A reflectance R1 of the first resonator mirror is wavelength-dependent, so that R1 or a product R of R1 and the reflectance R2 of the second resonator mirror in a wavelength range decreases from a target wavelength λ.sub.0 of the laser to λ.sub.0+Δλ from a value R0, wherein Δλ is selected as a function of a temperature-dependent shift in an emission wavelength.

A radiation-emitting semiconductor chip includes a semiconductor layer sequence having an active layer for generating electromagnetic radiation. The semiconductor chip also includes a reflector at a side surface of the semiconductor layer sequence having a reflector surface facing the semiconductor layer sequence and extending obliquely with respect to the active layer. The semiconductor chip further includes a top surface extending transversely with respect to the reflector surface and having a first emission region. The semiconductor chip additionally includes a further reflector situated opposite the reflector. The semiconductor chip is configured such that electromagnetic radiation generated in the active layer during operation is reflected by the reflector and emerges from the semiconductor chip via the emission region of the top surface. A main emission direction of the emerging electromagnetic radiation together with the active layer form an emergence angle of between 30° and 80° inclusive.