An optical semiconductor device outputting a predetermined wavelength of laser light includes a quantum well active layer positioned between a p-type cladding layer and an n-type cladding layer in thickness direction. The optical semiconductor device includes a separate confinement heterostructure layer positioned between the quantum well active layer and the n-type cladding layer. The optical semiconductor device further includes an electric-field-distribution-control layer positioned between the separate confinement heterostructure layer and the n-type cladding layer and configured by at least two semiconductor layers having band gap energy greater than band gap energy of a barrier layer constituting the quantum well active layer. The quantum well active layer is doped with 0.3 to 1×10.sup.18/cm.sup.3 of n-type impurity.

A tunable laser system includes a tunable laser to be scanned over a range of frequencies and an interferometer having a plurality of interferometer outputs. At least two interferometer outputs of the plurality of interferometer outputs have a phase difference. A wavelength reference has a spectral feature within the range of frequencies, and the spectral feature does not change in an expected operating environment of the tunable laser. Processing circuitry uses the spectral feature and the plurality of interferometer outputs to produce an absolute measurement of a wavelength of the tunable laser and controls the tunable laser based on a comparison of the absolute measurement of the wavelength of the tunable laser with a setpoint wavelength.

A thermoelectric module includes a substrate; a thermoelectric element; a bonding portion including an electrode that bonds the substrate and the thermoelectric element; an organic material film that covers a front surface of the bonding portion; and an inorganic material film that covers the organic material film.

Provided herein is a semiconductor package and method of forming the same. The semiconductor package has a cap including a first window wafer with a first face and opposing second face, a second window wafer, and a perforated spacer wafer with through-holes extending therethrough. The first and second faces of the first window wafer are mutually parallel and at least one face includes an antireflective surface. The spacer wafer is disposed between the first and second window wafers with the first and second window wafers bonded to opposing faces of the spacer wafer. The window wafers and spacer wafer together define a cavity in the cap. An edge-emitting laser diode is disposed on a submount and configured to direct a laser beam at normal incidence to the first face of the first window wafer. The cap is mounted on the submount with the edge-emitting laser diode enclosed in the cavity.

Provided is an optical isolator including a semiconductor substrate, an optical attenuator and an optical amplifier aligned with each other on the semiconductor substrate, an input optical waveguide connected to the optical attenuator, and an output optical waveguide connected to the optical amplifier, wherein a gain of the optical amplifier decreases based on an intensity of light incident on the optical amplifier increasing, wherein a first input light incident on the optical attenuator through the input optical waveguide is output as a first output light through the output optical waveguide, and a second input light incident on the optical amplifier through the output optical waveguide is output as a second output light through the input optical waveguide, and wherein when an intensity of the first input light and an intensity of the second input light are equal, an intensity of the first output light is greater than an intensity of the second output light.

A disclosed semiconductor laser module includes a semiconductor laser device; a waveguide optical function device that has an incidence end on which laser light emitted from the semiconductor laser device is incident and that guides the incident light; and a protrusion that is provided on an extension line of a light path of the laser light emitted from the semiconductor laser device, the extension line extending beyond the incidence end.

Disclosed are an optical device capable of precise adjustment of optical output intensity, and a method for manufacturing an optical device. An optical device including a laser diode, according to one aspect of the present embodiment, comprises: a laser diode for outputting light having a predetermined wavelength; an optical output unit in which output light of the laser diode is optically coupled and the output of the optical device takes place; and an optical isolator disposed between the laser diode and the optical output unit. The output light of the laser diode passes through the optical isolator and the output of the optical device takes place through the optical output unit, and the intensity of the output light of the optical device is determined by the rotation of the optical isolator.

The present invention makes it possible to improve excitation efficiency in a fiber laser device provided with a TFB having an injection optical fiber not connected to an excitation light source. This fiber laser device is provided with: a plurality of excitation light sources, at least one fiber bundle that injects excitation light from the plurality of excitation light sources from a plurality of injection optical fibers and couples the excitation light to one optical fiber; and a cavity that introduces the excitation light coupled by the fiber bundle and amplifies and emits laser light. The number of the plurality of injection optical fibers of the fiber bundle is larger than the number of the plurality of excitation light sources, and a loop part is configured by connecting surplus injection optical fibers to which the excitation light is not injected among the plurality of injection optical fibers of the fiber bundle.

A visible light source includes a substrate, a vertical-cavity surface-emitting laser including an active semiconductor region configured to emit infrared light and a first reflector configured to reflect the infrared light emitted by the active semiconductor region, a second reflector configured to reflect the infrared light and form a vertical cavity for the infrared light with the first reflector, and one or more micro-resonators configured to receive the infrared light and generate visible light in one or more colors using the infrared light through optical parametric oscillation. The visible light source also includes one or more output couplers configured to couple the visible light in one or more colors from the one or more micro-resonators into free space or into a photonic integrated circuit.

A pluggable optical connector is configured to be insertable into and removable from an optical communication apparatus, and to be capable of communicating a modulation signal and a data signal with the optical communication apparatus. A wavelength-tunable light source is configured to output an output light and a local oscillation light. An optical transmission unit is configured to output an optical signal generated by modulating the output light in response to the modulation signal. An optical reception unit is configured to demodulate an optical signal received by using the local oscillation light to the data signal. Pluggable optical receptors are configured in such a manner that an optical fiber is insertable into and removable from the pluggable optical receptors, and configured to be capable of outputting the optical signal to the optical fiber and transferring the optical signal received thorough the optical fiber to the optical reception unit.