In some implementations, a thermally-controlled photonic structure may include a suspended region that is suspended over a substrate; a plurality of bridge elements connected to the suspended region and configured to suspend the suspended region over the substrate, where a plurality of openings are defined between the plurality of bridge elements; and at least one heater element having a modulated width disposed on the suspended region. The at least one heater element having the modulated width may include at least one section of a greater width and at least one section of a lesser width. The at least one section of the greater width may be in alignment with an opening of the plurality of openings and the at least one section of the lesser width may be in alignment with a bridge element of the plurality of bridge elements.

Embodiments of the present invention include an apparatus for generating laser radiation with a semiconductor substrate, an intermediate layer arranged on the semiconductor substrate, and a Lateral Current Injection (LCI) laser arrangement arranged on the intermediate layer, wherein the intermediate layer includes a cavity extending at least under a laser strip of the LCI laser arrangement.

A laser diode includes a ridge portion, channel portions located adjacent to the ridge portion such that the ridge portion is sandwiched, the channel portions being shorter in height than the ridge portion, terrace portions adjacent to opposite sides of the respective channel portions from the ridge portion and longer in height than the channel portions, supporting portions provided over the respective channel portions, separated from side surfaces of the ridge portion or side surfaces of terrace portions or both, and made of resin, a ceiling portion including first portions provided over the supporting portions and second portions continuous with the first portions and located over the respective channel portions with hollow portions interposed therebetween, the ceiling portion being made of resin, and a metal layer provided over the ceiling portion and connected to an upper surface of the ridge portion.

Provided is an optical semiconductor element including: a stacked structure body 20 formed of a first compound semiconductor layer 21, a third compound semiconductor layer (active layer) 23, and a second compound semiconductor layer 22. A fundamental mode waveguide region 40 with a waveguide width W.sub.1, a free propagation region 50 with a width larger than W.sub.1, and a light emitting region 60 having a tapered shape (flared shape) with a width increasing toward a light emitting end surface 25 are arranged in sequence.

Semiconductor device structures comprising laser diode cavities with at least one of a mode-selective filter and a phase-alignment element, and methods for their fabrication, are disclosed. An example device structure comprises a surface-etched grating distributed-feedback (SEG DFB) laser with a mode-selective reflector structure. The reflector structure is designed to provide higher pot feedback of the fundamental TE0 mode and suppression of higher order mode effects. The reflector structure may be a single interface (single facet) mirror type reflector comprising a spatially patterned reflector, or a multi-interface distributed Bragg reflector (DBR). A phase alignment element may be included to provide precise optical phase control. A photodetector for back-facet power monitoring may be included. A method of fabrication is disclosed, based on a self-aligned process in which DBR features are included on the same mask that is used for the DFB laser grating.

A reflector structure for a tunable laser and a tunable laser. A super structure grating is used as a reflector structure, and a suspended structure is formed around a region in which the super structure grating is located, to implement, using the suspended structure, thermal isolation around the region in which the super structure grating is located, and increase thermal resistance, such that less heat is lost, and heat is concentrated in the region in which the super structure grating is located, thereby improving thermal tuning efficiency of the reflector structure. Moreover, lateral support structures are disposed on two sides of the suspended structure, to provide a mechanical support for the suspended structure. In addition, regions in the super structure grating that correspond to any two lateral support structures on a same side of the suspended structure fall at different locations in a spatial period of the super structure grating.

The present disclosure relates to a three-dimensional cylindrical cavity-type laser system capable of supporting circumferential radial emission. A cylindrical ring waveguide provides optical confinement in the radial and axial dimensions thereby supporting a plurality of radial modes, one of a plurality of axial modes and a plurality of degenerate azimuthal modes. These modes constitute a set of traveling wave modes which propagate around the cylindrical ring waveguide possessing various degrees of optical confinement as quantified by their respective Q-factors. Index tailoring is used to tailor the radial refractive index profile and geometry of the waveguide to support radial modes possessing Q-factors capable of producing efficient radial emission, while gain tailoring is used to define a gain confining region which offsets modal gain factors of the modal constituency to favor a preferred set of modes supporting efficient radial emission out of the total modal constituency supported by the resonator.. Under appropriate pump actuation the selected modes produce circumferential laser radiation with the output surface comprising of the entire outer perimeter of the cylindrical ring waveguide. The design is applicable toward both micro-resonators and resonators much larger than the optical wavelength, enabling high output powers and scalability. The circumferential radial laser emission can be concentrated by positioning the cylindrical ring laser inside a three-dimensional conical mirror thereby forming a laser ring of light propagating in the axial dimension away from the surface of the laser, which can be subsequently collimated for focused using conventional optics.

A laser includes a substrate, first and second claddings, a gain medium, and multiple supports. The first cladding is spaced apart from the substrate by an air gap. A thickness of the first cladding in a vertical direction is in a range from 0.05-0.15 micrometers. The gain medium is disposed on the first cladding opposite the air gap. The second cladding is disposed on the gain medium opposite the first cladding. A thickness of the second cladding in the vertical direction is in a range from 0.05-0.15 micrometers. The supports are coupled to each of the substrate, the first cladding, the gain medium, and the second cladding to retain the first cladding, the gain medium, and the second cladding spaced apart from the substrate.

The present disclosure relates to a three-dimensional cylindrical cavity-type laser system capable of supporting circumferential radial emission. A cylindrical ring waveguide provides optical confinement in the radial and axial dimensions thereby supporting a plurality of radial modes, one of a plurality of axial modes and a plurality of degenerate azimuthal modes. These modes constitute a set of traveling wave modes which propagate around the cylindrical ring waveguide possessing various degrees of optical confinement as quantified by their respective Q-factors. Index tailoring is used to tailor the radial refractive index profile and geometry of the waveguide to support radial modes possessing Q-factors capable of producing efficient radial emission, while gain tailoring is used to define a gain confining region which offsets modal gain factors of the modal constituency to favor a preferred set of modes supporting efficient radial emission out of the total modal constituency supported by the resonator. Under appropriate pump actuation the selected modes produce circumferential laser radiation with the output surface comprising of the entire outer perimeter of the cylindrical ring waveguide. The design is applicable toward both micro-resonators and resonators much larger than the optical wavelength, enabling high output powers and scalability. The circumferential radial laser emission can be concentrated by positioning the cylindrical ring laser inside a three-dimensional conical mirror thereby forming a laser ring of light propagating in the axial dimension away from the surface of the laser, which can be subsequently collimated for focused using conventional optics.

According to an embodiment, a wavelength tunable laser comprising a gain region and a wavelength tunable area is disclosed. The wavelength tunable area comprises: a lower clad layer; a passive optical waveguide positioned on the lower clad layer; an upper clad layer positioned on the passive optical waveguide; a drive electrode positioned on the upper clad layer; a current blocking layer positioned on the drive electrode; a heater positioned on the current blocking layer; and a first insulating groove and a second insulating groove which are positioned so as to face each other with the passive optical waveguide therebetween.