Systems, methods, and other embodiments for a new compact narrowband diode-pumped solid-state laser device enabled by Volume Bragg Grating (VBG) technology and capable of operating at the watt or higher output power level. This laser is stable, operates in a transverse electromagnetic (TEM) output mode, and with a single-narrowband (<1 kHz FWHM) longitudinal mode with acceptable relative intensity noise (RIN) performance from 1-100 GHz. In a preferred embodiment of the present invention, the TEM output mode is a TEM.sub.00 Gaussian output mode.

A semiconductor light-emitting device is provided which includes: a wiring substrate; a semiconductor light-emitting element disposed above an upper surface of the wiring substrate; and a cap unit which covers the semiconductor light-emitting element. The wiring substrate includes: a first substrate; a first metal layer and a second metal layer that are spaced apart from each other above the first substrate; and a spacer layer disposed above the first substrate. The cap unit includes a bonding surface which is bonded to the wiring substrate. The bonding surface intersects the first metal layer and the second metal layer in a top view of the wiring substrate, and the spacer layer is disposed between the bonding surface and the first substrate, at a position different from positions of the first metal layer and the second metal layer.

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 optical semiconductor device is applied to a ridge-stripe type laser.

A semiconductor laser module that includes a package accommodating therein a plurality of optical components, includes: a semiconductor laser device that emits laser light toward one end side in the package; an optical fiber having an incident end of the laser light on another end side in the package, the another end being in an opposite direction of an emission direction in which the semiconductor laser device emits the laser light; and a turn-back unit that turns back the laser light toward the another end side in the package, the another end being in the opposite direction of the emission direction in which the semiconductor laser device emits the laser light, and outputs the laser light to the incident end of the optical fiber.

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.

A method includes providing a first plate for a front wall that defines a front surface of a recess to accommodate a laser diode, a second plate for a rear wall that defines a rear side of the recess, and a third plate for a main body that defines an upper side and lateral sides of the recess and is connected to the front wall and the rear wall. The third plate has through-holes arranged in a first direction and in a second directions orthogonal to the first direction. The plates are bonded together to produce a stacked body. The stacked body is cut along the first direction and the second direction to produce a plurality of caps from the stacked body. When cutting the stacked body along the first direction, a first incision is made along inner wall surfaces of through-holes adjacent along the first direction.

A semiconductor laser tuned with an acousto-optic modulator. The acousto-optic modulator may generate standing waves or traveling waves. When traveling waves are used, a second acousto-optic modulator may be used in a reverse orientation to cancel out a chirp created in the first acousto-optic modulator. The acousto-optic modulator may be used with standing-wave laser resonators or ring lasers.

A semiconductor laser module includes a package; a plurality of semiconductor laser elements provided in the package; a member having a plurality of mounting surfaces on which the semiconductor laser elements are mounted, the mounting surfaces being separated from a bottom surface of the package by respective distances, the distances being gradually different from each other in a manner that the mounting surfaces as a whole form a step-like form; a plurality of lenses collimating respective laser beams emitted from the semiconductor laser elements; a plurality of reflection mirrors reflecting the respective laser beams; a condenser lens unit condensing the laser beams; an optical fiber where the optical beams condensed by the condenser lenses are optically coupled; and an optical filter disposed on optical lines of the respective laser beams reflected by the reflection mirrors and reflecting light having wavelengths different from the wavelengths of the laser beams.

A technology of effectively interrupting light reflected from a wavelength selective filter so as not to be fed back to a laser diode chip in a semiconductor laser package having a function of adjusting a relative intensity ratio of a signal of “1” and a signal of “0” using an optical filter. Since an optical interruption device may effectively interrupt a light feedback to the laser diode chip by adjusting characteristics of a 45 degree partial reflection mirror in an existing TO-can type laser device having the 45 degree partial reflection mirror and additionally disposing one λ/4 waveplate, unlike previously known optical isolators using an existing Faraday rotator, the signals of “1” and “0” may be effectively adjusted in a TO-can type laser device having a small volume, thereby improving a function of communication.

An optical device may include a laser emitter to generate a first laser beam and a second laser beam with orthogonal polarization states. The optical device may include first and second photodetectors to generate respective first currents based on optical powers of the first and second laser beams. The optical device may include a polarization-based beam splitter to combine the first and second laser beams. The optical device may include a wavelength filter to filter the first and second laser beams based on respective wavelengths of the first and second laser beams. The optical device may include a third photodetector and a fourth photodetector to generate respective second currents based on optical powers of the first and second laser beams after filtration. The wavelengths of the first and second laser beams may be controlled based on the first currents and the second currents.