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.

A wavelength tunable laser device includes: a first mirror; a second mirror; an optical amplifier provided between the first mirror and the second mirror; a wavelength tunable filter provided between the first mirror and the second mirror; and an optical waveguide coupling the optical amplifier and the wavelength tunable filter. The optical waveguide includes a first waveguide formed with a first width and a second waveguide formed with a second width wider than the first width.

An optical device is provided that includes an active waveguide having a top electrode and a plurality of layers including a gain layer. Configurations are disclosed for the active waveguide to enable amplification of a guided optical wave profile while preserving a shape of a lateral optical intensity profile of the guided optical wave as the guided optical wave is amplified along the waveguide. The top electrode and/or one or more layers of the active optical waveguide may be tailored to provide a tailored optical gain.

Examples disclosed herein relate to quantum-dot (QD) photonics. In accordance with some of the examples disclosed herein, a QD semiconductor optical amplifier (SOA) may include a silicon substrate and a QD layer above the silicon substrate. The QD layer may include an active gain region to amplify a lasing mode received from an optical signal generator. The QD layer may have a gain recovery time such that the active gain region amplifies the received lasing mode without pattern effects. A waveguide may be included in an upper silicon layer of the silicon substrate. The waveguide may include a mode converter to facilitate optical coupling of the received lasing mode between the QD layer and the waveguide.

In an optical device, a first semiconductor layer and a second semiconductor layer are formed to be thinner than a core, an active layer has a shape with an end in a waveguide direction tapers toward a tip end, the first semiconductor layer having a trapezoidal shape with a width thereof decreases toward a side of a third semiconductor layer from a side of the core in a plan view and a width thereof decreases as one end in the waveguide direction recedes from a central portion of the active region, and the second semiconductor layer having a trapezoidal shape with a width thereof decreases toward a side of a fourth semiconductor layer from the side of the core in a plan view and a width thereof decreases as one end in the waveguide direction recedes from the central portion of the active region.

Provided are a lens, a stem, an LD chip to emit laser light with a beam center directed along a mounting surface of the stem, and a PD chip having a reflective surface formed with a dielectric multilayer film on its surface, reflecting the laser light emitted from the LD chip toward the lens, and measuring an amount of the laser light, wherein the LD chip is provided with a waveguide portion having a tip portion that is formed on a side of a front end face and has a width of 0.5 to 0.7 μm, and having a tapered portion that is connected to the tip portion and becomes narrower toward the tip portion at a gradient of 0.018 to 0.033.

A semiconductor laser diode is specified, the semiconductor laser diode includes a semiconductor layer sequence having an active layer having a main extension plane and which, in operation, is configured to generate light in an active region and emit light via a light-outcoupling surface, the active region extending from a back surface opposite the light-outcoupling surface to the light-outcoupling surface along a longitudinal direction in the main extension plane, the semiconductor layer sequence having a surface region on which a first cladding layer is applied in direct contact, the first cladding layer having a transparent material from a material system different from the semiconductor layer sequence, and the first cladding layer being structured and having a first structure.

The present disclosure relates to index guided semiconductor laser devices supporting wide single lateral mode operation for high power operation. A narrow channel ridge waveguide structure is presented which devices can be configured as single lateral multi-spectral high power semiconductor lasers, single frequency lasers, gain chips and semiconductor amplifiers. More specifically it relates to a means for increasing the lateral mode size over that of conventional index guided structures to increase the average output power typically limed by Catastrophic Optical Damage (COD) at the laser facet or by intensity related effects. This potentially allows the overall laser cavity length to be shortened for a given output power level to stabilize frequency locking with internal or external gratings to improve single frequency operation.

A semiconductor optical device includes an SOI substrate having a waveguide of silicon, and at least one gain region of a group III-V compound semiconductor having an optical gain bonded to the SOI substrate. The waveguide has a bent portion and multiple linear portions extending linearly and connected to each other through the bent portion. The gain region is disposed on each of the multiple linear portions.

A semiconductor optical device includes a light emitting layer that emits light in a state of current injection; an optical waveguide in which a width or a thickness in an extending direction (y) of the light emitting layer varies along the extending direction; and a uniform diffraction grating having constant cycle, width and depth, wherein the light emitting layer, the optical waveguide and the uniform diffraction grating are arranged at positions where the light emitting layer, the optical waveguide, and the uniform diffraction grating are optically coupled to one another, the uniform diffraction grating is arranged above the light emitting layer, the optical waveguide is arranged below the light emitting layer, and the optical waveguide includes, in the extending direction, a first portion having a predetermined width, a second portion having a larger width than the width of the first portion, and a third portion having the same width as the width of the first portion.