Narrow-optical linewidth laser generation devices and methods for generating a narrow-optical linewidth laser beam are provided. One narrow-optical linewidth laser generation devie includes a single-wavelength mirror or multiwavelength mirror (for comb lasers) formed from one or more optical ring resonators coupled with an optical splitter. The optical splitter may in turn be coupled with a quantum dot optical amplifier (QDOA), itself coupled with a phase-tuner. The phase tuner may be further coupled with a broadband mirror. The narrow-optical linewidth laser beam is generated by using a long laser cavity and additionally by using an integrated optical feedback.

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.

Embodiments of the present disclosure include optical transmitters and transceivers with improved reliability. In some embodiments, the optical transmitters are used in network devices, such as in conjunction with a network switch. In one embodiment, lasers are operated at low power to improve reliability and power consumption. The output of the laser may be modulated by a non-direct modulator and received by integrated optical components, such as a modulator and/or multiplexer. The output of the optical components may be amplified by a semiconductor optical amplifier (SOA). Various advantageous configurations of lasers, optical components, and SOAs are disclosed. In some embodiments, SOAs are configured as part of a pluggable optical communication module, for example.

In one embodiment of the invention, a semiconductor optical amplifier (SOA) in a laser ring is chosen to provide low polarization-dependent gain (PDG) and a booster semiconductor optical amplifier, outside of the ring, is chosen to provide high polarization-dependent gain. The use of a semiconductor optical amplifier with low polarization-dependent gain nearly eliminates variations in the polarization state of the light at the output of the laser, but does not eliminate the intra-sweep variations in the polarization state at the output of the laser, which can degrade the performance of the SS-OCT system.

Embodiments of the present disclosure include optical transmitters and transceivers with improved reliability. In some embodiments, the optical transmitters are used in network devices, such as in conjunction with a network switch. In one embodiment, lasers are operated at low power to improve reliability and power consumption. The output of the laser may be modulated by a non-direct modulator and received by integrated optical components, such as a modulator and/or multiplexer. The output of the optical components may be amplified by a semiconductor optical amplifier (SOA). Various advantageous configurations of lasers, optical components, and SOAs are disclosed. In some embodiments, SOAs are configured as part of a pluggable optical communication module, for example.

A laser light source includes an inner ring and an outer ring. The inner ring includes a semiconductor optical amplifier (SOA), a pair of optical circulators, a first optical filter, and a first optical waveguide connecting those in series. The outer ring includes the SOA, a pair of optical circulators, a second optical filter, an output port, and a second optical waveguide connecting those in series except for a portion shared. The inner ring operates as a gain-clamped SOA with a feedback control light defined by the first optical filter. The outer ring generates a laser output in a gain region of the clamped SOA, and with multiple peak wavelengths defined by the second optical filter, in a range from L Band to U band, applicable to WDM network systems. A WDM network system and a method of controlling the laser light source are also disclosed.

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.

Photonic chip includes an external cavity (EC) optical circuit to provide wavelength-selective optical feedback to a length of active optical fiber. Light generated in the active optical fiber may be coupled from the EC circuit to a light processing circuit of the photonic chip, such as an optical modulator or an optical mixer. The EC circuits may include single-frequency and multi-frequency optical filters, which may include ring resonators, dual-ring resonators, and optical modulators to support multi-frequency lasers. The EC circuits may further include pump combiners and optical isolators.

A fiber optic ring laser, and non-transitory computer readable medium for using a fiber optic ring laser are disclosed. The disclosed fiber optic ring laser includes a semiconductor booster optical amplifier (BOA), as a gain medium; a Fiber Fabry Perot Tunable Filter (FFP-TF), as a wavelength selection element; an optical isolator (ISO) to insure unidirectional operation of the fiber optic ring laser; and a polarization controller (PC) for attaining an optimized polarization state in order to achieve a stable-generated output in terms of output power and wavelength, wherein the BOA, the FFP-TF, the ISO and the PC are coupled to form a ring configuration that implements a continuously tunable booster amplifier-based fiber ring laser.

The invention may be embodied in other forms than those specifically disclosed herein without departing from itMulti-kW-class blue (400-495 nm) fiber-delivered lasers and module configurations. In embodiments, the lasers propagate laser beams having beam parameter products of <5 mm*mrad, which are used in materials processing, welding and pumping a Raman laser. In an embodiment the laser system is an integration of fiber-coupled modules, which are in turn made up of submodules. An embodiment has sub-modules having a plurality of lensed blue semiconductor gain chips with low reflectivity front facets. These are locked in wavelength with a wavelength spread of <1 nm by using volume Bragg gratings in an external cavity configuration. An embodiment has modules having of a plurality of submodules, which are combined through wavelength multiplexing with a bandwidth of <10 nm, followed by polarization beam combining. The output of each module is fiber-coupled into a low NA fiber. In an embodiment a kW-level blue laser system is realized by fiber bundling and combining multiple modules into a single output fiber.