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.

A multi-wavelength multi-port laser and router. By arranging a reflective facet at one end of the port-selection semiconductor optical amplifier and a partial reflector at one end of the wavelength-selection semiconductor optical amplifier, and cooperating with the intra-cavity wavelength router to form N×N optical resonant cavities, so that each optical resonant cavity can only emit the wavelength corresponding to the lowest round-trip loss between input and output ports. The extra-cavity wavelength router is mirrored with respect to the intra-cavity wavelength router, so that one or more wavelengths of light excited by any port-selection semiconductor optical amplifier can be transmitted from the corresponding output port of the extra-cavity wavelength router. The switching of the wavelength and output ports of the router is performed by on-off switching of the port-selection semiconductor optical amplifier and wavelength-selection semiconductor optical amplifier, and the switching time can be less than 1 ns.

A discrete wavelength tunable laser having an optical cavity which comprises: a reflective semiconductor optical amplifier (SOA); a demultiplexer (Demux) having a single input and a plurality of outputs, the Demux configured to receive the output of the SOA and to produce a plurality of fixed spectral passbands within the gain bandwidth of the SOA; one or more tunable distributed Bragg reflector(s) (DBR(s)) arranged to receive the outputs of the Demux, each tunable DBR configured to select a reflective spectral band within the gain bandwidth of the SOA upon application of a bias current; wherein the SOA forms the back end mirror of the optical cavity; the one or more tunable DBRs form the front end mirror of the optical cavity; and wherein the lasing channel of the discrete wavelength tunable laser is chosen by the overlap of the selected reflective spectral band of one of the one or more tunable DBRs with a fixed spectral passband of the Demux.

In at least one embodiment, the optoelectronic semiconductor device comprises a carrier, a first semiconductor laser configured to emit a first laser radiation and applied on the carrier, and a multi-mode waveguide configured to guide the first laser radiation and also applied on the carrier, wherein the multi-mode waveguide comprises at least one furcation and a plurality of branches connected by the at least one furcation.

A quantum cascade laser includes a first and a second mesa waveguides disposed on a substrate, a first electrode, a second electrode, and a current blocking region disposed burying the first and second mesa waveguides. The first and second mesa waveguides extend in a first direction. The first and second mesa waveguides are arranged apart from each other by a distance in a second direction intersecting with the first direction. The current blocking region has a first portion disposed between the first and second mesa waveguides and a second portion disposed on the first portion. The end of the first electrode and the end of the second electrode are facing each other in the second direction. The second portion protrudes from a reference plane which includes a surface of the end of the first electrode and extends in the first and second directions.

A semiconductor laser device includes a submount, a semiconductor laser element, and a bonding material. The semiconductor laser element includes a substrate and a layered structure, and is disposed with the layered structure facing the submount. A waveguide extending in a first direction parallel to the main surface of the substrate is formed in the layered structure. The bonding material includes an inner region bonded to the semiconductor laser element and one outer region located outward of the inner region. The one outer region is spaced apart from one side surface of the semiconductor laser element. Width A of the semiconductor laser element and width B of the one outer region in a second direction perpendicular to the first direction and parallel to the main surface of the substrate satisfy B≥A/4.

Disclosed are a design method, a product and an application of a high-repetition-frequency and multi-wavelength ultrashort pulse mode-locked photonic integrated chip. Components for designing the mode-locked photonic integrated chip include a semiconductor optical amplifier array providing gains for N wavelength channels; a phase delay line array which includes phase delay lines with different lengths and separately compensates for different effective optical path differences of gain light of the wavelength channels caused by a dispersion effect; a flattened arrayed waveguide grating multiplexing the gain light with the effective optical path differences compensated, and multiplexing N-channel optical pulse signals into one-channel optical pulse signal; a saturable absorber forming, with the arrayed waveguide grating, N individual and synchronized different wavelength mode-locked optical pulse channels; and a semiconductor optical amplifier used for gaining and outputting an output pulse of the saturable absorber.

A photonic device for providing light radiation comprises a wave guide, an N-type semiconductor layer covering the wave guide and an active region formed by a stack of layers made of III-V materials. The photonic device also comprises a plurality of P-type semiconductor pillars arranged on, and in contact with, the active region. At least a first metal pad is in ohmic contact with the free portion of the N-type layer and at least a second metal pad is in ohmic contact with the P-type pillars.

A grating emitter method and system for modulating the polarization of an optical beam, such as one for transmission through free-space or use in an atomic clock.

A monolithically integrated optical device. The device has a gallium and nitrogen containing substrate member having a surface region configured on either a non-polar or semi-polar orientation. The device also has a first waveguide structure configured in a first direction overlying a first portion of the surface region. The device also has a second waveguide structure integrally configured with the first waveguide structure. The first direction is substantially perpendicular to the second direction.