An edge-emitting semiconductor laser diode chip 15 with mutually opposed front and back end facet mirrors 22, 24. First and second ridges 26.sub.1, 26.sub.2 extend between the chip end facets 22, 24 to define first and second waveguides in an active region layer. Low and high slope efficiency laser diodes are thus formed that are independently drivable by respective electrode pairs 21.sub.1, 23.sub.1 and 21.sub.2, 23.sub.2. The single chip 15 thus incorporates two laser diodes sharing a common heterostructure, one with low slope efficiency optimized for low power operation with good power stability against temperature variations and random threshold current fluctuations in the close-to-threshold power regime, and the other with high slope efficiency optimized for high wall plug efficiency operation at higher output powers when the chip is operating far above threshold.

A tunable laser for a transceiver includes a silicon photonics substrate, first and second patterned regions each being defined in the substrate a step lower than a flat surface region of the substrate, first and second laser diode chips arranged in the first and second patterned regions, the patterned regions being configured to align the gain regions of the first and second laser diode chips with integrated couplers formed in the substrate adjacent to the first and second patterned regions to facilitate flip-bonding the first and second laser diode chips within the patterned regions, and a tuning filter coupled to the first laser diode chip and the second laser diode chip via the integrated couplers. The tuning filter is configured to receive laser light from each of the first and second laser diode chips and generate a laser output having a gain determined by each of the gain regions.

Building blocks are provided for on-chip chemical sensors and other highly-compact photonic integrated circuits combining interband or quantum cascade lasers and detectors with passive waveguides and other components integrated on a III-V or silicon. A MWIR or LWIR laser source is evanescently coupled into a passive extended or resonant-cavity waveguide that provides evanescent coupling to a sample gas (or liquid) for spectroscopic chemical sensing. In the case of an ICL, the uppermost layer of this passive waveguide has a relatively high index of refraction that enables it to form the core of the waveguide, while the ambient air, consisting of the sample gas, functions as the top cladding layer. A fraction of the propagating light beam is absorbed by the sample gas if it contains a chemical species having a fingerprint absorption feature within the spectral linewidth of the laser emission.

Building blocks are provided for on-chip chemical sensors and other highly-compact photonic integrated circuits combining interband or quantum cascade lasers and detectors with passive waveguides and other components integrated on a III-V or silicon. A MWIR or LWIR laser source is evanescently coupled into a passive extended or resonant-cavity waveguide that provides evanescent coupling to a sample gas (or liquid) for spectroscopic chemical sensing. In the case of an ICL, the uppermost layer of this passive waveguide has a relatively high index of refraction that enables it to form the core of the waveguide, while the ambient air, consisting of the sample gas, functions as the top cladding layer. A fraction of the propagating light beam is absorbed by the sample gas if it contains a chemical species having a fingerprint absorption feature within the spectral linewidth of the laser emission.

Building blocks are provided for on-chip chemical sensors and other highly-compact photonic integrated circuits combining interband or quantum cascade lasers and detectors with passive waveguides and other components integrated on a III-V or silicon. A MWIR or LWIR laser source is evanescently coupled into a passive extended or resonant-cavity waveguide that provides evanescent coupling to a sample gas (or liquid) for spectroscopic chemical sensing. In the case of an ICL, the uppermost layer of this passive waveguide has a relatively high index of refraction that enables it to form the core of the waveguide, while the ambient air, consisting of the sample gas, functions as the top cladding layer. A fraction of the propagating light beam is absorbed by the sample gas if it contains a chemical species having a fingerprint absorption feature within the spectral linewidth of the laser emission.

A tunable laser for a transceiver includes a silicon photonics substrate, first and second patterned regions each being defined in the substrate a step lower than a flat surface region of the substrate, first and second laser diode chips arranged in the first and second patterned regions, the patterned regions being configured to align the gain regions of the first and second laser diode chips with integrated couplers formed in the substrate adjacent to the first and second patterned regions to facilitate flip-bonding the first and second laser diode chips within the patterned regions, and a tuning filter coupled to the first laser diode chip and the second laser diode chip via the integrated couplers. The tuning filter is configured to receive laser light from each of the first and second laser diode chips and generate a laser output having a gain determined by each of the gain regions.

A monolithic InP-based PIC having a first photonic assembly that has a first optical splitter-combiner unit having a first end part that is optically connected with a first optical waveguide and a second end part that is optically connected with a first main photonic circuit and a first auxiliary photonic circuit. The first auxiliary photonic circuit has a first laser unit, and a first SOA. The first SOA is configurable to be in a first operational state in which the first SOA allows optical communication between the first laser unit and the first optical splitter-combiner unit, or a second operational state in which the first SOA prevents optical communication between the first laser unit and the first optical splitter-combiner unit. An opto-electronic system including the PIC.

A tunable laser that includes an array of parallel optical amplifiers is described. The laser may also include an intracavity N×M coupler that couples power between a cavity mirror and the array of parallel optical amplifiers. Phase adjusters in optical paths between the N×M coupler and the optical amplifiers can be used to adjust an amount of power output from M−1 ports of the N×M coupler. A tunable wavelength filter is incorporated in the laser cavity to select a lasing wavelength.

Disclosed are photonic particles and methods of using particles in biological samples. The particles are configured to emit laser light when energetically stimulated by, e.g., a pump source. The particles may include a gain medium with inorganic materials, an optical cavity with high refractive index, and a coating with organic materials. The particles may be smaller than 3 microns along their longest axes. The particles may attach to each other to form, e.g., doublets and triplets. The particles may be injection-locked by coupling an injection beam into a particle while pumping so that an injection seed is amplified to develop into laser oscillation. A microscopy system may include a pump source, beam scanner, spectrometer with resolution of less than 1 nanometer and acquisition rate of more than 1 kilohertz, and spectral analyzer configured to distinguish spectral peaks of laser output from broadband background.

An optical apparatus includes a light emitting module having a light emitting device, the light emitting device having a first semiconductor layer, a core layer, and a second semiconductor layer laminated in order, and an optical element on which a light emitted from the light emitting module is incident. The first semiconductor layer, the core layer, and the second semiconductor layer are arranged along a lamination direction. The lamination direction is inclined with respect to a direction perpendicular to an optical axis of the optical element.