A photodetector is positioned so that imaginary lines perpendicular to an emission end surface of a first light-emitting element through first and second points, respectively, pass through the photodetector. The first and second points are two points at which an imaginary line parallel to the emission end surface through an inside of an outer edge of the first light-emitting element intersects the outer edge of the first light-emitting element in a top view. At least a part of a first wiring region is arranged in a first region between imaginary lines perpendicular to the emission end surface through third and fourth points, respectively. The third and fourth points are two points at which an imaginary line parallel to the emission end surface through an inside of an outer edge of the photodetector intersects the outer edge of the photodetector in the top view.

An optical sensor system includes a set of epitaxial layers formed on a semiconductor substrate. The set of epitaxial layers defines a semiconductor laser having a first multiple quantum well (MQW) structure. Electromagnetic radiation is generated by the first MQW structure, emitted from the first MQW structure, and self-mixed with a portion of the emitted electromagnetic radiation that is returned to the first MQW structure. The set of epitaxial layers also defines a second MQW structure operable to generate a first photocurrent responsive to detecting a first emission of the semiconductor laser, and a third MQW structure operable to generate a second photocurrent responsive to detecting a second emission of the semiconductor laser. The optical sensor system also includes a circuit configured to generate a self-mixing interferometry (SMI) signal by combining the first photocurrent and the second photocurrent.

Examples described herein relate to an optical device with an integrated light-emitting structure to generate light and a waveguide integrated capacitor to monitor light. The light-emitting structure may emit light upon the application of electricity to the optical device. The waveguide integrated capacitor may be formed under the light-emitting structure to monitor the light emitted by the light-emitting structure. The waveguide integrated capacitor includes a waveguide region carrying at least a portion of the light. The waveguide region includes one or more photon absorption sites causing the generation of free charge carriers relative to an intensity of the light confined in the waveguide region resulting in a change in the conductance of the waveguide region.

The present invention provides methods and an apparatus for monitoring the optical output power of a laser diode (LD) having an associated photodiode (PD), and a particle sensor apparatus. The photodiode (PD) is operable together with the laser diode (LD), wherein it detects the light (LS) of the laser diode (LD) and converts it into an electrical current, and is thermally coupled to the laser diode (LD). Monitoring of the optical output power P is effected during the operation of the laser diode (LD) and is based on current measurements and/or voltage measurements at the laser diode (LD) and at the photodiode (PD).

A light source includes a substrate with a first surface and an opposite second surface. An epitaxial layer is positioned on the first surface of the substrate. The light source also includes at least one light generator in the epitaxial layer positioned such that an optical signal transmitted thereby is directed toward the substrate. A diffuser is positioned on the second surface of the substrate, and at least one monitor photodetector is positioned in the epitaxial layer in an arrangement configured to receive a portion of the optical signal which is reflected by the diffuser. In one form, the light generator may include a vertical cavity surface emitting laser (VCSEL).

An opto-electronic system including a PIC that includes a semiconductor-based tunable laser source that can achieve single-mode lasing thereby emitting optical radiation having a predefined linewidth at a predefined operating wavelength. The PIC also includes an optical measurement unit that can receive the optical radiation emitted by said laser source, and provide a signal representative for the received optical radiation to a control unit of the opto-electronic system that is operatively connected with said laser source and the optical measurement unit. The opto-electronic system enables omitting external optical measurement equipment thereby enabling a faster and cheaper way of locking of the predefined operating wavelength of said laser and achieving the predefined linewidth. A method of improved tuning of a semiconductor-based tunable laser source of an opto-electronic system.

A wideband electro-absorption modulating (EAM) device is configured to include a ground shield that functions to minimize the spread of an applied AC voltage beyond the limits of the modulator's electrode. The ground shield includes a grounding electrode disposed in a spaced-apart relationship with the modulator electrode along the ridge of the EAM structure, and a grounding termination used to couple the grounding electrode to a suitable ground location. The ground location may be either on-chip (such as the DC ground of the modulator itself) or off-chip (via an off-chip capacitor, with a wirebond connecting the grounding electrode to the capacitor). The use of a ground shield mitigates the effects that changes in the data rate have on effective length of the modulator as seen by the applied data signal.

A chip scale ultra violet laser source includes a plurality of laser elements on a substrate each including a back cavity mirror, a tapered gain medium, an outcoupler, a nonlinear crystal coupled to the outcoupler with a front facet that has a first coating that is anti-reflectivity (AR) to a fundamental wavelength of the laser element and high reflectivity (HR) to ultra violet wavelengths, and has an exit facet that has a second coating that has HR to a fundamental wavelength of the laser element and AR to the ultra violet wavelengths, a photodetector coupled to the outcoupler, a phase modulator coupled to the photodetector and coupled to the back cavity mirror, and a master laser diode on the substrate coupled to the phase modulator of each laser element. Each laser element emits an ultra violet beamlet and is frequency and phase locked to the master laser diode.

A sensor system includes a self-mixing interferometry sensor; a drive circuit configured to apply a modulated drive signal to an input of the self-mixing interferometry sensor; a mixer circuit configured to mix a modulated output of the self-mixing interferometry sensor with a local oscillator signal that is orthogonal to the modulated drive signal over a period of time; an integrator circuit configured to integrate an output of the mixer circuit over the period of time; and a processor configured to determine, using an output of the integrator circuit, at least one of a round-trip propagation time of electromagnetic radiation emitted by the self-mixing interferometry sensor and reflected back into the self-mixing interferometry sensor by an object or medium, or a velocity of the object or medium.

Apparatuses and methods for a temperature insensitive electro-absorption modulator and laser. The device comprising a laser capable of emitting light. The laser itself includes a laser gain section, a first mirror and a second mirror. Each of the mirrors are coupled to the laser gain section. The laser gain section contains quantum wells. The first mirror and the second mirror have a wavelength bandwidth sufficient for a lasing wavelength range of the laser. A modulator is coupled to the laser to receive the light and is capable of modulating the light to vary the output from the modulator. The modulator contains quantum wells and has a quantum well confinement factor that is greater than 0.1. An output coupler is coupled to the modulator and the output coupler has a back reflection that is less than half of a back reflection of the second mirror. The laser has a lasing wavelength that tracks the absorption spectrum of the modulator. The device is operated at a temperature range comprising a first temperature and a second temperature, wherein the second temperature is greater than the first temperature by at least 15 degrees Celsius.