In order to prevent non-uniformity in emission wavelength among different sites along an optical axis direction, provided is a resonator portion including: a waveguide which includes a first area and a second area being adjacent to the first area; and diffraction gratings formed along an optical axis direction. The effective refraction index in the first area is larger than the one in the second area, and the thickness in the first area is larger than the one in the second area. A pitch at the adjacent diffraction gratings at a boundary between the first area and the second area is narrower both than pitches of the diffraction gratings that are formed in the first area and than pitches of the diffraction gratings that are formed in the second area.

In various embodiments, the beam parameter product and/or numerical aperture of a laser beam is adjusted utilizing a step-clad optical fiber having a central core, a first cladding, an annular core, and a second cladding.

Embodiments herein describe optical assemblies that use a spacer element to attach and align a laser to a waveguide in a photonic chip. Once aligned, the laser can transfer optical signals into the photonic chip which can then perform an optical function such as modulation, filtering, amplification, and the like. In one embodiment, the spacer element is a separate part (e.g., a glass or semiconductor block) that is attached between the photonic chip and a submount on which the laser is mounted. The spacer establishes a separation distance between the photonic chip and the submount which in turn aligns the laser with the waveguide in the photonic chip. In another embodiment, rather than the spacer element being a separate part, the spacer element may be integrated into the submount.

An integrated structure and method of formation provide a lower level waveguide having a core of a first material and a higher level waveguide having a core of a second material and a coupling region for coupling the two waveguides together. The different core materials provided different coupled waveguides having different light loss characteristics.

An airborne particle-measuring device quantifies and qualifies contaminants of an air environment in clean-rooms, open spaces, and enclosed spaces such as homes, offices, industrial environments, airplanes in flight, cars and others. The device may include a sensor system, an electronics system, communications and information storage. The sensor system may include a high-power low-wavelength single-frequency continuous laser, an open-cavity high-efficiency mirror having an optical surface tuned to the laser frequency and a flow system that includes a vacuum pump to sample the air. The electronics system may be mounted on a single multilayer PC board with a microprocessor, firmware, electronics and a touch-screen LCD display. Innovations in light source, flow control, analog and digital signal processing, components integration and software allow provision of equipment in a wide range of high-complexity settings that require precise particle measurements.

Apparatuses and methods for photonic communication and photonic addressing are disclosed herein. An example apparatus includes a photonic source layer that provides a plurality of photonic sources, each at a different wavelength, a plurality of second layers, and a third layer. Each of the plurality of second layers may be associated with a respective wavelength, and each of the plurality of second layers may include photonic filters tuned to their respective wavelength, a photonic modulator, and a photonic detector. The third layer may include a plurality of photonic circuits, with each of the plurality of photonic circuits associated with a respective second layer of the plurality of second layers. Additionally, each of the plurality of photonic circuits may include a photonic filter tuned to a respective wavelength associated with a respective second layer, a photonic detector and a photonic modulator. Modulated and unmodulated photonic signals may be provided from the second layers to the third layer and from the third layer to the second layers, where the respective wavelengths of the photonic signals acts like an address for each of the plurality of second layers.

An optical waveguide includes a core, a first cladding, a second cladding, and a heater. The first cladding configured to cover the core. The second cladding disposed over the first cladding. The heater disposed over the second cladding to heat the core. The first cladding and the second cladding are silicon oxide films. A first fixed charge density of the first cladding is lower than a second fixed charge density of the second cladding.

A 400 Gb/s transmitter is integrated on a silicon substrate. The transmitter uses four gain chips, sixteen lasers, four modulators to modulate the sixteen lasers at 25 Gb/s, and four multiplexers to produce four optical outputs. Each optical output can transmit at 100 Gb/s to produce a 400 Gb/s transmitter. Other variations are also described.

A photonic device includes a semiconductor wafer having a waveguide formed therein. An end of the waveguide includes a step. The photonic device further includes a semiconductor chip bonded to the semiconductor wafer and having an active region, and a waveguide coupler disposed in a gap between a sidewall of the semiconductor chip and the end of the waveguide. The waveguide coupler includes an optical bridge that has a first end and a second end opposing the first end. The first end of the optical bridge is interfaced with a facet of the active region of the semiconductor chip. The second end of the optical bridge is interfaced with the end of waveguide, and has a portion thereof disposed over the step at the end of the waveguide.

A semiconductor laser has a mirror formed in a gain chip. The mirror can be placed in the gain chip to provide a broadband reflector to support multiple lasers using the gain chip. The mirror can also be placed in the gain chip to have the semiconductor laser be more efficient or more powerful by changing an optical path length of the gain of the semiconductor laser.