A semiconductor optical amplifier for high-power operation includes a gain medium having a multilayer structure sequentially laid with a P-layer, an active layer, a N-layer from an upper portion to a lower portion in cross-section thereof. The gain medium is extendedly laid with a length L from a front facet to a back facet. The active layer includes multiple well layers formed by undoped semiconductor material and multiple barrier layers formed by n-doped semiconductor materials. Each well layer is sandwiched by a pair of barrier layers. The front facet is characterized by a first reflectance Rf and the back facet is characterized by a second reflectance Rb. The gain medium has a mirror loss α.sub.m about 40-200 cm.sup.−1 given by: α.sub.m=(½L)ln{1/(Rf×Rb)}.

A light source device includes: a plurality of light sources that generate rays of light with different wavelengths corresponding to a plurality of target wavelengths located on a designated wavelength grid; a plurality of photodetectors that detect output powers of the plurality of light sources; a plurality of optical bandpass filters that are provided between the plurality of light sources and the plurality of photodetectors; a temperature adjustment unit that adjusts a temperature of an area around the plurality of light sources; and a processor that controls the temperature adjustment unit based on output signals of the plurality of photodetectors. Widths of passbands of the optical bandpass filters are less than a wavelength spacing in the wavelength grid.

The present application provides a radiation output device and a method. The radiation output device includes a radiation generating module configured to generate initial radiation; a filter module configured to reflect a portion of a first preset wavelength of the initial radiation to the radiation generating module and transmit a portion of a second preset wavelength of the initial radiation, the transmitted radiation is therefore used as an output radiation of the radiation output device; a detection feedback module, using a portion of or all of the output radiation as a feedback radiation, configured to instruct a modulating module to modulate the filter module according to the feedback radiation. The modulating module is connected to the filter module and configured to modulate a position and/or an angle of the filter module according to the instruction of the detection feedback module.

An optical member includes: a main body having transparency or heat dissipation properties; an optical film disposed on an upper face of the main body; a metal film disposed on the upper face of the main body in a region other than a region where the optical film is disposed; a surrounding part joined via the metal film; and a wavelength conversion part surrounded by the surrounding part. The wavelength conversion part is positioned inward of a periphery of the optical film in a top view. The wavelength conversion part is not directly bonded to the optical film and the main body.

Techniques and systems for a semiconductor laser, namely a grating-coupled surface-emitting (GCSE) comb laser, having thermal management for facilitating dissipation of heat, integrated thereon. The thermal management is structured in manner that prevents deformation or damage to the GCSE laser chips included in the semiconductor laser implementation. The disclosed thermal management elements integrated in the laser can include: heat sinks; support bars; solder joints; thermal interface material (TIM); silicon vias (TSV); and terminal conductive sheets. Support bars, for example, having the GCSE laser chip positioned between the bars and having a height that is higher than a thickness of the GCSE laser chip. Accordingly, the heat sink can be placed on top of the support bars such that heat is dissipated from the GCSE laser chip, and the heat sink is separated from directed contact with the GCSE laser chip due to the height of the support bars.

A photonic integrated circuit (PIC) includes various mode field adapters (MFAs), a waveguide, and various contact pads. All the MFAs are on a same facet of the PIC. One MFA of the PIC outputs a first optical signal that is an amplified version of a second optical signal. The waveguide is divided into two waveguide arms and a bend portion to join the two waveguide arms. The waveguide extends between the MFAs such that the second optical signal propagates through the waveguide. Further, each waveguide arm is formed between the contact pads. The second optical signal propagating through the waveguide is amplified based on a current that is injected in the PIC by way of the contact pads.

A laser for a distributed fiber sensing system may have a frequency discriminator integrated with the laser. The laser may be an external cavity laser, with at least a portion of the laser cavity on a planar lightwave circuit, which also includes the frequency discriminator.

An electronic device includes a base substrate having a mounting face. An electronic chip is fastened onto the mounting face of the base substrate. A transparent encapsulation structure is bonded onto the base substrate. The transparent encapsulation structure includes a housing with an internal cavity defining a chamber housing the electronic chip. The encapsulation structure has an external face that supports a light-filtering optical wafer located facing an optical element of the electronic chip. An opaque cover covers the transparent encapsulation structure and includes a local opening facing the light-filtering optical wafer.

Methods, circuits, and techniques for reflection cancellation. Laser output is tapped. A tapped portion of the laser output is phase shifted to generate a feedback signal, with the feedback signal being out-of-phase with a parasitic reflection of the laser output. The feedback signal is directed towards the laser such that the parasitic reflection and feedback signal are superpositioned before entering the laser. A magnitude and a phase of the feedback signal are such that superposition of the feedback signal and the parasitic reflection results in a resulting signal of lower magnitude than the parasitic reflection alone. During laser operation, a magnitude of the resulting signal is monitored and, as the parasitic reflection varies, the magnitude of the resulting signal is adjusted by adjusting at least one of the magnitude and the phase of the feedback signal in response to the monitoring of the resulting signal.

Apparatus, systems and methods to spectrally beam combine a group of diode lasers in an external cavity arrangement. A dichroic beam combiner or volume Bragg grating beam combiner is placed in an external cavity to force each of the diode lasers or groups of diode lasers to oscillate at a wavelength determined by the passband of the beam combiner. In embodiments the combination of a large number of laser diodes in a sufficiently narrow bandwidth to produce a high brightness laser source that has many applications including as to pump a Raman laser or Raman amplifier.