A tunable laser includes a reflective semiconductor optical amplifier (SOA), a grating codirectional coupler, and a reflective microring resonator. The grating codirectional coupler and the reflective microring resonator are both formed on a silicon base. An anti-reflection film is disposed on a first end surface of the reflective SOA, and the first end surface is an end surface, coupled to a first waveguide of the grating codirectional coupler, of the reflective SOA. A second waveguide of the grating codirectional coupler is coupled to the first waveguide, a first grating is disposed on the first waveguide, a second grating disposed opposite to the first grating is disposed on the second waveguide, and the first grating and the second grating constitute a narrow-band pass filter. The second waveguide is connected to the reflective microring resonator.

A semiconductor ring laser including a closed loop laser cavity and an optical gain device that is optically interconnected with the closed loop laser cavity. The optical gain device includes a first optical gain segment and a second optical gain segment. The first optical gain segment and the second optical gain segment being non-identical, optically interconnected with each other, and electrically isolated from each other. A PIC including a semiconductor ring laser and to an opto-electronic system that includes a PIC. The opto-electronic system can be one of a transmitter, a receiver, a transceiver, a coherent transmitter, a coherent receiver and a coherent transceiver. The opto-electronic system can for example, but not exclusively, be used for telecommunication applications, LIDAR or sensor applications.

There is provided a device to generate an output light. The device comprises a substrate, a quantum well structure (QWS) disposed on the substrate, and a waveguide disposed on the substrate and in contact with the QWS. The QWS has a first layer, a second layer, and a third layer. The second layer is disposed and quantum-confined between the first layer and the third layer. In addition, the second layer is to emit an input light when electrically biased. The input light has an optical field extending outside the QWS and into the waveguide, to optically couple the waveguide with the QWS. The waveguide is to provide an optical resonance cavity for the input light. Moreover, the waveguide has an optical outlet to transmit at least some of the input light out of the waveguide to generate the output light.

A photonic integrated circuit device includes a lasing cavity for resonating at a plurality of discrete wavelengths and an optical feedback cavity operably coupled to the lasing cavity via a front surface of the lasing cavity. The optical feedback cavity has a reflective element for reflecting light, at least partially, back into the lasing cavity to form a resonant Fabry-Perot cavity between the front surface and the reflective element. The optical feedback cavity includes a variable phase shifting element adapted for receiving an input signal to control a phase shift of light propagating in the optical feedback cavity. The amount of light entering the lasing cavity from the optical feedback cavity is low enough to avoid dynamic instability of the lasing cavity. The reduction in light is obtained using an attenuator.

Provided here are: a semiconductor laser section formed on a surface of a semiconductor substrate; a spot-size converter section in which an optical waveguide having a core layer for propagating laser light emitted from the semiconductor laser section is provided; and a monitor PD section which is provided on the spot-size converter section laterally with respect to a propagation direction of the laser light; wherein, the regions of a PD anode electrode and a PD cathode electrode in the monitor PD section are partially opposed to each other through an insulating film, so that the surge breakdown voltage of the monitor PD section is increased.

In the present disclosure, in an EADFB laser in which an SOA has been integrated, a new configuration in which deterioration of optical waveform quality is solved or mitigated while keeping characteristics that a manufacturing process can be simplified by using the same layer structure is indicated. In the optical transmitter of the present disclosure, a waveguide structure having a tapered structure in at least a part of the SOA waveguide is adopted. A width of the waveguide is changed to be reduced in an SOA region, and an amount of carrier consumption is made uniform in an optical waveguide direction. A waveguide width is continuously reduced in an optical waveguide direction in the SOA so that the optical confinement coefficient is reduced, and light power distributed in an active layer region is made constant.

Systems and methods here may include improved tunable lasers having a tunable filter and a tunable channel selector that can control precisely the wavelength and the bandwidth of the light emitted by the laser, while suppressing light that may otherwise be emitted by the laser outside the desired wavelength and bandwidth with unidirectional ring lasers having a resonator of which forms a ring and where light propagates only in one of the two possible directions.

A QCL may include a substrate, an emitting facet, and semiconductor layers adjacent the substrate and defining an active region. The active region may have a longitudinal axis canted at an oblique angle to the emitting facet of the substrate. The QCL may include an optical grating being adjacent the active region and configured to emit one of a CW laser output or a pulsed laser output through the emitting facet of substrate.

A high Q whispering gallery mode resonator with ion-implanted voids is described. A resonator device includes a resonator disk formed of an electrooptic material. The resonator disk includes a top surface, a bottom surface substantially parallel to the top surface, and a side structure between the top surface and the bottom surface. The side structure includes an axial surface along a perimeter of the resonator disk, where a midplane passes through the axial surface dividing the axial surface into symmetrical halves. The whispering gallery mode resonator disk includes voids localized at a particular depth from the top surface. At least one of the voids localized at the particular depth from the top surface is located at an outer extremity towards the perimeter of the resonator disk. The resonator device can further include a first electrode on the top surface and a second electrode on the bottom surface.

A light source module includes a first semiconductor laser element hermetically sealed, a second semiconductor laser element hermetically sealed, and firth to fourth optical elements. A first laser beam prior to reaching the first optical element has divergence angle θfd1 in a direction along a second optical axis and divergence angle θsd1 in a direction along a third optical axis, and satisfy 90°>θfd1>θsd1>0°. Divergence angle θfd12 of a first laser beam in the direction along the second optical axis decreases from divergence angle θfd1, the first laser beam having exited the first optical element. A component of a first laser beam in the direction along the second optical axis is collimated, the first laser beam having exited the second optical element. The same applies to the second semiconductor laser element.