Various technologies described herein pertain to injection locking on-chip laser(s) and external on-chip resonator(s). A system includes a first integrated circuit chip and a second integrated circuit chip. The first integrated circuit chip and the second integrated circuit chip are separate integrated circuit chips and can be optically coupled to each other. The first integrated circuit chip includes a laser configured to emit light via a first path and a second path. The second integrated circuit chip includes a resonator formed of an electrooptic material. The resonator can receive the light emitted by the laser of the first integrated circuit chip via the first path and return feedback light to the laser of the first integrated circuit chip via the first path. The feedback light can cause injection locking of the laser to the resonator to control the light emitted by the laser (e.g., via the first and second paths).

Various technologies described herein pertain to injection locking on-chip laser(s) and external on-chip resonator(s). A system includes a first integrated circuit chip and a second integrated circuit chip. The first integrated circuit chip and the second integrated circuit chip are separate integrated circuit chips and can be optically coupled to each other. The first integrated circuit chip includes a laser configured to emit light via a first path and a second path. The second integrated circuit chip includes a resonator formed of an electrooptic material. The resonator can receive the light emitted by the laser of the first integrated circuit chip via the first path and return feedback light to the laser of the first integrated circuit chip via the first path. The feedback light can cause injection locking of the laser to the resonator to control the light emitted by the laser (e.g., via the first and second paths).

A light source based on an optical frequency mixer is disclosed. The light source has a first laser for emitting light at a first optical frequency, and a plurality of second lasers for emitting light at different second optical frequencies. The optical frequency mixer provides output light beams at mixed optical frequencies of the first and second lasers. Wavelength of output light beams may be tuned by tuning wavelength of any of the first or second lasers. In this manner, RGB wavelength-tunable light sources may be constructed based on red or near-infrared lasers. The wavelength tunability of the output light beams may be used to angularly scan or refocus the light beams.

A transistor for emitting laser with a fixed frequency includes a first region, a second region, at least one quantum well, and a third region. The at least one quantum well is installed in the second region, and the second region is coupled between the first region and the third region. When one of the first region, the second region, and the third region receives two signals, or two of the first region, the second region, and the third region receive the two signals respectively, the at least one quantum well emits the laser with the fixed frequency.

A method for generating light emission is provided. The method includes providing a transistor element including collector, emitter, and base regions, a quantum cascade region between the base and collector regions, and quantum well structures for interband emission within the base or emitter regions. A waveband controller applies, via first and second electrodes with respect to the collector and base regions, a first electrical signal to control a base-collector junction bias level and select between first and second base-collector bias levels. Selection of the first base-collector bias level causes at least one of the emitter and base regions to produce interband-based light emission having a first wavelength of a first wavelength band. Selection of the second base-collector bias level causes the quantum cascade region to produce intraband-based light emission having a second wavelength of a second wavelength band.

A transistor for emitting laser with a fixed frequency includes a first region, a second region, at least one quantum well, and a third region. The at least one quantum well is installed in the second region, and the second region is coupled between the first region and the third region. When one of the first region, the second region, and the third region receives two signals, or two of the first region, the second region, and the third region receive the two signals respectively, the at least one quantum well emits the laser with the fixed frequency.

Various technologies described herein pertain to injection locking on-chip laser(s) and external on-chip resonator(s). A system includes a first integrated circuit chip and a second integrated circuit chip. The first integrated circuit chip and the second integrated circuit chip are separate integrated circuit chips and can be optically coupled to each other. The first integrated circuit chip includes a laser configured to emit light via a first path and a second path. The second integrated circuit chip includes a resonator formed of an electrooptic material. The resonator can receive the light emitted by the laser of the first integrated circuit chip via the first path and return feedback light to the laser of the first integrated circuit chip via the first path. The feedback light can cause injection locking of the laser to the resonator to control the light emitted by the laser (e.g., via the first and second paths).

A method for generating light emission is provided. The method includes providing a transistor element including collector, emitter, and base regions, a quantum cascade region between the base and collector regions, and quantum well structures for interband emission within the base or emitter regions. A waveband controller applies, via first and second electrodes with respect to the collector and base regions, a first electrical signal to control a base-collector junction bias level and select between first and second base-collector bias levels. Selection of the first base-collector bias level causes at least one of the emitter and base regions to produce interband-based light emission having a first wavelength of a first wavelength band. Selection of the second base-collector bias level causes the quantum cascade region to produce intraband-based light emission having a second wavelength of a second wavelength band.

This disclosure relates to semiconductor quantum cascade lasers (QCLs). A three-terminal QCL device is disclosed. The three-terminal QCL device includes a unipolar multi-period quantum cascade laser structure embedded in a bipolar structure having three terminals providing at least two independently controllable biases to the QCL device for adjusting the lasing intensity and for tuning the lasing wavelength of the QCL device. The three-terminal QCL device further includes a quantum impedance matching structure for achieving high efficiency carrier injection and lowering lasing threshold. In addition, the multi-period quantum cascade laser structure is selectively doped to provide near charge neutrality during operation. The three-terminal QCL may further be controlled to achieve simultaneous dual- or multi-color lasing.

A light source based on an optical frequency mixer is disclosed. The light source has a first laser for emitting light at a first optical frequency, and a plurality of second lasers for emitting light at different second optical frequencies. The optical frequency mixer provides output light beams at mixed optical frequencies of the first and second lasers. Wavelength of output light beams may be tuned by tuning wavelength of any of the first or second lasers. In this manner, RGB wavelength-tunable light sources may be constructed based on red or near-infrared lasers. The wavelength tunability of the output light beams may be used to angularly scan or refocus the light beams.