A method for physical random number generation includes the steps of: modulating the gain of a vertical-cavity surface-emitting laser periodically from the lower threshold to the upper threshold and back; maintaining the gain per round trip positive for a longer period than the round trip time of the cavity; maintaining the net gain per round trip negative for a longer period than the round trip time of the cavity, in order to create optical pulses of random amplitude; detecting the optical pulses; converting the optical pulses into electrical analog pulses; and digitising the electrical analog pulses into random numbers.

An optical emitter includes a vertical cavity surface emitting laser (VCSEL), an equalization circuit coupled to the VCSEL; and a current source coupled to the VCSEL and the equalization circuit. The equalization circuit is configured to divert a first current from the current source to the VCSEL at a first data frequency and divert a second current greater than the first current from the current source to the VCSEL at a second data frequency higher than the first data frequency.

A pulsed laser diode array driver includes an inductor having a first terminal configured to receive a source voltage, a source capacitor coupled between the first terminal of the inductor and ground, a bypass capacitor connected between a second terminal of the inductor and ground, a bypass switch connected between the second terminal of the inductor and ground, a laser diode array with one or more rows of laser diodes, and one or more laser diode switches, each being connected between a respective row node of the laser diode array and ground. The laser diode switches and the bypass switch are configured to control a current flow through the inductor to produce respective high-current pulses through each row of the laser diode array, each of the high-current pulses corresponding to a peak current of a resonant waveform developed at that row of the laser diode array.

An optical semiconductor chip of the present disclosure includes a high frequency line between an electrode pad receiving a modulation signal and a modulation electrode on the optical waveguide constituting a laser. The depletion layer capacitance generated in an active layer of the optical waveguide is cancelled by an inductance component of the high frequency line. When a portion directly below the high frequency line is embedded with a low-dielectric-constant material or is made hollow, the parasitic capacitance is further reduced. The high frequency line may have a zigzag shape as well as a linear shape. The electrode pad on the optical semiconductor chip can be connected to other substrates including RF lines for modulation signal input by bumps or wire bonding.

An optical modulator carrier assembly includes a optical modulator, a transmission line substrate, a first via, a second via and a wire having an inductor component provided on a second surface of the transmission line substrate, and electrically connecting between the another end of the first via and the another end of the second via. The one end of the first via, the cathode electrode pad, the terminating resistor, the one end of the second via are arranged on the in this order.

In an EADFB laser with an integrated SOA, a new configuration in which deterioration of optical waveform quality is solved or mitigated while taking advantage of characteristics that the same layer structure can be used and the manufacturing process can be simplified is shown. In an optical transmitter of the present disclosure, a carrier density is optimized depending on a light intensity inside the SOA and an amount of carrier consumption. The SOA is electrically separated into a plurality of regions, and a current is injected into each region independently. The divided SOA region is configured so that a length of the SOA region becomes shorter as a region is farther from an incidence end of the SOA. Further, for the divided SOA, an amount of carrier consumption increases as the SOA region is farther from the incidence end, so that a current injection amount is increased.

An electronic-element mounting package includes a wiring substrate having a first surface and a wiring pattern thereon; a base having a second surface and a through hole whose opening is on the second surface; a signal line penetrating the through hole and having a first end exposed from an opening of the through hole; and an insulating member between an inner surface of the through hole and the signal line and has an end portion and a main portion. The end portion has an end surface on a side of the opening of the through hole, and the main portion is farther from the opening of the through hole than the end portion. The electronic-element mounting package also has a conductive joining material with which the wiring pattern and the first end are joined. Permittivity of the end portion is larger than permittivity of the main portion.

[Object] To provide a vertical cavity surface emitting laser element having excellent electric responsiveness and high productivity and reliability, a method of producing the vertical cavity surface emitting laser element, and a photoelectric conversion apparatus.

[Solving Means] A vertical cavity surface emitting laser element according to the present technology includes: a semiconductor stacked body. The semiconductor stacked body is a semiconductor stacked body that includes a first mirror having a first conductive type, a second mirror that has a second conductive type and causes optical resonance together with the first mirror, an active layer provided between the first mirror and the second mirror, and a confinement layer that is provided between the first mirror and the second mirror and has a non-oxidized region and an oxidized region, the non-oxidized region being formed of a first material, the oxidized region being provided around the non-oxidized region and being formed of a second material obtained by oxidizing the first material, and has a mesa having an outer peripheral surface from which end surfaces of the active layer and the confinement layer are exposed and an ion implantation region that is a region into which ions have been implanted, is formed to reach a predetermined depth in the active layer and the confinement layer from the outer peripheral surface, and is separated from the non-oxidized region.

An optical semiconductor chip of the present disclosure includes a high frequency line between an electrode pad receiving a modulation signal and a modulation electrode on the optical waveguide having a light absorption layer. The depletion layer capacitance generated in the light absorption layer is canceled by an inductor component of the high frequency line. When a portion directly below the high frequency line is embedded with a low-dielectric-constant material or is made hollow, the parasitic capacitance is further reduced. The high frequency line may have a zigzag shape as well as a linear shape. The electrode pad on the optical semiconductor chip can be connected to other substrates including RF lines for modulation signal input by bumps or wire bonding.

An optoelectronic semiconductor device is disclosed wherein the device is a vertical-cavity surface-emitting laser or a photodiode containing a section, the top part of which is electrically isolated from the rest of the device. The electric isolation can be realized by etching a set of holes and selective oxidation of AlGaAs layer or layers such that the oxide forms a continuous layer or layers everywhere beneath the top surface of this section. Alternatively, a device can be grown epitaxially on a semi-insulating substrate, and a round trench around a section of the device can be etched down to the semi-insulating substrate thus isolating this section electrically from the rest of the device. Then if top contact pads are deposited on top of the electrically isolated section, the pads have a low capacitance, and a pad capacitance below two hundred femto-Farads, and the total capacitance of the device below three hundred femto-Farads can be reached.