Disclosed is a Vernier effect DBR laser that has uniform laser injection current pumping along the length of the laser. The laser can include one or more tuning elements, separate from the laser injection element, and these tuning elements can be used to control the temperature or modal refractive index of one or more sections of the laser. The refractive indices of each diffraction grating can be directly controlled by temperature changes, electro optic effects, or other means through the one or more tuning elements. With direct control of the temperature and/or refractive indices of the diffraction gratings, the uniformly pumped Vernier effect DBR laser can be capable of a wider tuning range. Additionally, uniform pumping of the laser through a single electrode can reduce or eliminate interfacial reflections caused by, for example, gaps between metal contacts atop the laser ridge, which can minimize multi-mode operation and mode hopping.

A 1.3 μm-band wavelength-tunable DBR laser in which a wavelength-tunable amount is extended is disclosed. The wavelength-tunable DBR laser according to an embodiment of the present invention is a wavelength-tunable DBR laser in which an active region having an optical gain and a DBR region including a diffraction grating are integrated monolithically and an oscillation wavelength is changed by injecting a current into the DBR region. At a boundary between a p-side clad layer and a core layer in the DBR region, an electron barrier layer being p-type doped and having a bandgap greater than in the p-side clad layer is further included. At a boundary between an n-side clad layer and the core layer in the DBR region, a hole barrier layer being n-type doped and having a bandgap greater than in the n-side clad layer is further included.

A recording head includes an external cavity laser with an externally mounted part having an active region. The external cavity laser also includes a channel waveguide that delivers light towards a media-facing surface. A near-field transducer functions as a reflector, either alone or in combination with a Bragg grating in the channel waveguide. A reflective back facet of the externally mounted part and the reflector define a resonator of the external cavity laser.

Disclosed are a wavelength-selectable laser diode and an optical communication apparatus including the same. The wavelength-selectable laser diode includes a substrate, which includes a gain region, a tuning region spaced apart from the gain region, and a phase adjusting region between the tuning region and the gain region, a waveguide layer on the substrate, a clad layer on the waveguide layer, and gratings disposed on the substrate or the clad layer in the gain region and the tuning region.

Embodiments of the present disclosure may relate to a digitized grating that may include a first unit cell that has a first period and a first length, where the first period includes a first grating element width and a first space between adjacent grating elements, and where the first length includes a number of first periods. The digitized grating may further include a second unit cell that has a second period and a second length, where the second period is different than the first period and includes a second grating element width and a second space between adjacent grating elements, and where the second length includes a number of second periods.

An optical device according to the embodiment of the inventive concept includes a waveguide path including a light generation region, a wavelength variable region, and a light modulation region, a first light waveguide layer provided in the light generation region to generate light, a second light waveguide layer provided in the wavelength variable region and connected to the first light waveguide layer, a ring-shaped third light waveguide layer provided in the light modulation region and connected to the second light waveguide layer, and first and second light modulation electrodes spaced apart from each other with the light modulation region therebetween. Here, the first light modulation electrode, the third light waveguide layer, and the second light modulation electrode vertically overlap each other.

An optical device according to the embodiment of the inventive concept includes a waveguide path including a light generation region, a wavelength variable region, and a light modulation region, a first light waveguide layer provided in the light generation region to generate light, a second light waveguide layer provided in the wavelength variable region and connected to the first light waveguide layer, a ring-shaped third light waveguide layer provided in the light modulation region and connected to the second light waveguide layer, and first and second light modulation electrodes spaced apart from each other with the light modulation region therebetween. Here, the first light modulation electrode, the third light waveguide layer, and the second light modulation electrode vertically overlap each other.

A thermally tunable laser includes: a substrate; a laser resonator, wherein the laser resonator includes a gain section, and wherein the laser resonator includes a tuning section; a heating arrangement; a heat sink arrangement for dissipating a heat flow from the laser resonator to the heat sink arrangement; and a hole arrangement for influencing the heat flow from the laser resonator to the heat sink arrangement, wherein the hole arrangement is arranged between the substrate and the heat sink arrangement, wherein one or more holes of the hole arrangement include at least one hole being arranged within a horizontal range of the tuning section, so that a thermal resistance between the tuning section and the heat sink arrangement is increased.

A 1.3 m-band wavelength-tunable DBR laser in which a wavelength-tunable amount is extended is disclosed. The wavelength-tunable DBR laser according to an embodiment of the present invention is a wavelength-tunable DBR laser in which an active region having an optical gain and a DBR region including a diffraction grating are integrated monolithically and an oscillation wavelength is changed by injecting a current into the DBR region. At a boundary between a p-side clad layer and a core layer in the DBR region, an electron barrier layer being p-type doped and having a bandgap greater than in the p-side clad layer is further included. At a boundary between an n-side clad layer and the core layer in the DBR region, a hole barrier layer being n-type doped and having a bandgap greater than in the n-side clad layer is further included.

A laser device includes front and back DBRs and an interferometer. The front DBR is coupled to a front DBR electrode. The front DBR forms a first tunable multi-peak lasing filter. The back DBR is coupled to a back DBR electrode. The back DBR forms a second tunable multi-peak lasing filter. The interferometer part is coupled between the front DBR and the back DBR. The interferometer part includes first and second waveguide combiners and first and second interferometer waveguides coupled therebetween. The first waveguide combiner couples the interferometer part to the back DBR. The second waveguide combiner couples the interferometer part to the front DBR. The first interferometer waveguide is coupled to an interferometer electrode. The interferometer forms a third tunable multi-peak lasing filter.