A controller stabilizes a distributed feedback plus reflection (DFB+R) laser, which has a back facet, a DFB section, a passive section, and a front facet with a low reflective element. An etalon filter is formed by a portion of the DFB section, the passive section, and the low reflective element. Control circuitry directly modulates the DFB section with a modulation signal and biases the passive section with a bias signal. In operation, a lasing mode of the DFB section is aligned to a long wavelength edge of one of the periodic peaks of a reflection profile of the etalon filter. Meanwhile, photodiodes are arranged to monitor the output power emitted from the laser's front and back facets. The control circuitry monitors a ratio of the detected output power and adjusts the bias based on the monitored ratio.

A surface-emitting laser includes a substrate; semiconductor layers provided on the substrate, the semiconductor layers including a lower reflector layer, an active layer, and an upper reflector layer, the semiconductor layers forming a mesa; a first insulating film covering the mesa; and a second insulating film covering the first insulating film, wherein the mesa has a polygonal shape in a direction in which the substrate extends, and a vertex of the mesa in the direction in which the substrate extends has a chamfered portion.

A circuit (e.g., for use in a time-of-flight camera projector module) may include a top metal layer having an anode and a cathode, one or more capacitors connected to the anode, a vertical-cavity surface-emitting laser connected to the anode and the cathode, and a driver connected to the cathode. The circuit may further include a bottom metal layer connected to ground and arranged below the top metal layer, and a dielectric layer separating the top metal layer and the bottom metal layer. In some implementations, the dielectric layer has a thickness under sixty micrometers and a thermal resistance under fifteen degrees Celsius per watt. Accordingly, a current loop flowing vertically across the dielectric layer has a low self-inductance based on the thickness of the dielectric layer and the bottom metal layer is arranged to dissipate heat generated by the current loop flowing vertically across the dielectric layer.

An optical semiconductor element having a mesa portion includes a substrate and semiconductor layers on the substrate. The optical semiconductor element further includes a first contact electrode, a second contact electrode on the semiconductor layer, first and second lead-out wires connected to the first and second contact electrodes, respectively, and an insulating film covering at least an upper surface of the semiconductor layer and the second contact electrode. The second lead-out wire is connected to the second contact electrode in an opening of the insulating film. An outer peripheral end of the second contact electrode in at least a portion where the second contact electrode and the second lead-out wire are connected is above and outside an outer peripheral end of a connection portion with the semiconductor layer, and an inner peripheral end is above and inside an inner peripheral end of the connection portion with the semiconductor layer.

An optical semiconductor element having a mesa portion includes a substrate and semiconductor layers on the substrate. The optical semiconductor element further includes a first contact electrode, a second contact electrode on the semiconductor layer, first and second lead-out wires connected to the first and second contact electrodes, respectively, and an insulating film covering at least an upper surface of the semiconductor layer and the second contact electrode. The second lead-out wire is connected to the second contact electrode in an opening of the insulating film. An outer peripheral end of the second contact electrode in at least a portion where the second contact electrode and the second lead-out wire are connected is above and outside an outer peripheral end of a connection portion with the semiconductor layer, and an inner peripheral end is above and inside an inner peripheral end of the connection portion with the semiconductor layer.

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.

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.

The present disclosure is generally directed to an EML with a filter layer disposed between an active region of the EML and a substrate of the EML to absorb a portion of unmodulated light energy, and preferably the unmodulated light energy caused by transverse electric (TE) substrate mode. The filter layer preferably comprises a material with an energy band gap (Eg) that is less than the energy band gap of the predetermined channel wavelength to absorb unmodulated laser light.

A semiconductor laser has a mirror formed in a gain chip. The mirror can be placed in the gain chip to provide a broadband reflector to support multiple lasers using the gain chip. The mirror can also be placed in the gain chip to have the semiconductor laser be more efficient or more powerful by changing an optical path length of the gain of the semiconductor laser.

A semiconductor laser has a mirror formed in a gain chip. The mirror can be placed in the gain chip to provide a broadband reflector to support multiple lasers using the gain chip. The mirror can also be placed in the gain chip to have the semiconductor laser be more efficient or more powerful by changing an optical path length of the gain of the semiconductor laser.