Examples disclosed herein relate to quantum-dot (QD) photonics. In accordance with some of the examples disclosed herein, a QD semiconductor optical amplifier (SOA) may include a silicon substrate and a QD layer above the silicon substrate. The QD layer may include an active gain region to amplify a lasing mode received from an optical signal generator. The QD layer may have a gain recovery time such that the active gain region amplifies the received lasing mode without pattern effects. A waveguide may be included in an upper silicon layer of the silicon substrate. The waveguide may include a mode converter to facilitate optical coupling of the received lasing mode between the QD layer and the waveguide.

Described herein are photonic integrated circuits (PICs) comprising a semiconductor optical amplifier (SOA) to output a signal comprising a plurality of wavelengths, a sensor to detect data associated with a power value of each wavelength of the output signal of the SOA, a filter to filter power values of one or more of the wavelengths of the output signal of the SOA, and control circuitry to control the filter to reduce a difference between a pre-determined power value of each filtered wavelength of the output signal of the SOA and the detected power value of each filtered wavelength of the output signal of the SOA.

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.

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.

A disclosed semiconductor laser module includes a semiconductor laser device; a semiconductor optical amplifier configured to receive laser light emitted from the semiconductor laser device and amplify the laser light that has been received; and a first light receiving device that measures an intensity of a part of the laser light emitted from the semiconductor laser device, for monitoring a wavelength of the laser light, wherein the semiconductor optical amplifier is located rearward in relation to a light receiving surface of the first light receiving device along a propagation direction of the laser light emitted from the semiconductor device.

A disclosed semiconductor laser module includes a semiconductor laser device; a semiconductor optical amplifier configured to receive laser light emitted from the semiconductor laser device and amplify the laser light that has been received; and a first light receiving device that measures an intensity of a part of the laser light emitted from the semiconductor laser device, for monitoring a wavelength of the laser light, wherein the semiconductor optical amplifier is located rearward in relation to a light receiving surface of the first light receiving device along a propagation direction of the laser light emitted from the semiconductor device.

A semiconductor optical amplifier integrated laser includes a semiconductor laser oscillator portion that oscillates laser light having a wavelength included in a gain band and a semiconductor optical amplifier portion that amplifies laser light output from the semiconductor laser oscillator portion. The semiconductor laser oscillator portion and the semiconductor optical amplifier portion have one common p-i-n structure, the common p-i-n structure includes an active layer, a cladding layer provided apart from the active layer, and a common functional layer formed in the cladding layer, and the common functional layer includes a first portion that reflects light having a wavelength within the gain band in the semiconductor laser oscillator portion and a second portion that transmits light having a wavelength within the gain band in the semiconductor optical amplifier portion.

A semiconductor optical amplifier integrated laser includes a semiconductor laser oscillator portion that oscillates laser light having a wavelength included in a gain band and a semiconductor optical amplifier portion that amplifies laser light output from the semiconductor laser oscillator portion. The semiconductor laser oscillator portion and the semiconductor optical amplifier portion have one common p-i-n structure, the common p-i-n structure includes an active layer, a cladding layer provided apart from the active layer, and a common functional layer formed in the cladding layer, and the common functional layer includes a first portion that reflects light having a wavelength within the gain band in the semiconductor laser oscillator portion and a second portion that transmits light having a wavelength within the gain band in the semiconductor optical amplifier portion.

A photonic integrated circuit (PIC) includes a semiconductor substrate, one or more passive components, and one or more active components. The one or more passive components are fabricated on the semiconductor substrate, wherein the passive components are fabricated in a III-V type semiconductor layer. The one or more active components are fabricated on top of the one or more passive components, wherein optical signals are communicated between the one or more active components via the one or more passive components.

An optical apparatus comprises a semiconductor substrate and a slab-coupled optical waveguide (SCOW) emitter disposed on the semiconductor substrate. The SCOW emitter comprises an optical waveguide comprising: a first region doped with a first conductivity type; a second region doped with a different, second conductivity type; and an optically active region disposed between the first region and the second region. The optically active region comprises a plurality of quantum dots.