A semiconductor light emitting device includes a microstrip substrate with a single-ended transmission line on a top surface, wherein the single-ended transmission line extends from a first end portion to a second end portion, the microstrip substrate has a ground plane on a bottom surface, and the ground plane is opposed and bonded to the conductive pattern. The single-ended transmission line includes a first section and a second section, wherein the second section extends from the first section and includes the second end portion. The second section is lower in characteristic impedance than the first section. A load circuit that includes the wire, the optical modulator, and the termination resistor is electrically connected between the second end portion and the conductive pattern. The load circuit is equal to or lower in the characteristic impedance than the second section.

An optical semiconductor module according to an embodiment includes a housing; a temperature control element having a temperature control plane; a first board mounted on the temperature control plane; a semiconductor laser device mounted on the second side of the first board; a second board mounted on the second side of the first board, the second board having a third side and a fourth side, the fourth side including a wiring pattern, the wiring pattern being electrically connected with the housing via a first bonding wire and electrically connected to the semiconductor laser device via a second bonding wire, the second board having a second thermal conductivity smaller than the first thermal conductivity. The housing is configured to accommodate the temperature control element, the first board, the second board, and the semiconductor laser device.

An edge-emitting semiconductor laser diode chip 15 with mutually opposed front and back end facet mirrors 22, 24. First and second ridges 26.sub.1, 26.sub.2 extend between the chip end facets 22, 24 to define first and second waveguides in an active region layer. Low and high slope efficiency laser diodes are thus formed that are independently drivable by respective electrode pairs 21.sub.1, 23.sub.1 and 21.sub.2, 23.sub.2. The single chip 15 thus incorporates two laser diodes sharing a common heterostructure, one with low slope efficiency optimized for low power operation with good power stability against temperature variations and random threshold current fluctuations in the close-to-threshold power regime, and the other with high slope efficiency optimized for high wall plug efficiency operation at higher output powers when the chip is operating far above threshold.

A monolithic laser device assembly 10A in the present disclosure includes a first gain portion 20 having a first end portion 20A and a second end portion 20B, a second gain portion 30 having a third end portion 30A and a fourth end portion 30B, one or multiple ring resonators 40, a semiconductor optical amplifier 50 for amplifying a laser light emitted from the first gain portion 20, and a pulse selector 60 disposed between the first gain portion 20 and the semiconductor optical amplifier 50, in which the ring resonator 40 is optically coupled with the first gain portion 20 and with the second gain portion 30, and laser oscillation is performed on either the first gain portion 20 or the second gain portion 30.

A broad-spectrum laser for use in a MEMS laser scanning display device is provided. In one example, the broad-spectrum laser includes a laser diode emitter with plural quantum wells each having a different spectral peak. In another example, the broad-spectrum laser includes a laser diode emitter with a tunable absorber to achieve a broadened emissions spectrum. In another example, the broad-spectrum laser includes a laser diode emitter array having plural individual emitters with different spectral peaks.

A Vertical Cavity Surface Emitting Laser (VCSEL) has a mesa having an active region, which has m active layer structures (with m≥2). The active layer structures are electrically connected to each other by a tunnel junction therebetween. The mesa has an optical resonator, which has first and second DBRs. The active region is between the first and second DBRs. The VCSEL has first and second electrical contacts, which provide electrical current to the active region, and an electrical control contact, which controls gain-switched laser emission of the VCSEL by at least 1 up to m−1 active layer structures by a current between the electrical control contact and the first or second electrical contact. A current aperture is between the active region and the first or second electrode. A distance between the current aperture and a furthest active layer structure is at least three times the laser light's wavelength.

A semiconductor laser drive circuit includes: an anode electrode divided into at least one gain region and at least one light absorption region; a cathode electrode shared between the gain region and the light absorption region; and a resistance connected to the anode electrode of the light absorption region.

A Dense Wavelength Division Multiplexing (DWDM) photonic integration circuit (PIC) that implements a DWDM system, such as a transceiver, is described. The DWDM PIC architecture includes photonic devices fully integrating on a single manufacturing platform. The DWDM PIC has a multi-wavelength optical laser, a quantum dot (QD) laser with integrated heterogeneous metal oxide semiconductor (H-MOS) capacitor, integrated on-chip. The multi-wavelength optical laser can be a symmetric comb laser that generates two equal outputs of multi-wavelength light. Alternatively, the DWDM PIC can be designed to interface with a stand-alone multi-wavelength optical laser that is off-chip. In some implementations, the DWDM PIC integrates multiple optimally designed photonic devices, such as a silicon geranium (SiGe) avalanche photodetector (APD), an athermal H-MOS wavelength splitter, a QD photodetector, and a heterogenous grating coupler. Accordingly, fabricating the DWDM PIC includes a unique III-V to silicon bonding process, which is adapted for its use of SiGe APDs.

A broad-spectrum laser for use in a MEMS laser scanning display device is provided. In one example, the broad-spectrum laser includes a laser diode emitter with plural quantum wells each having a different spectral peak. In another example, the broad-spectrum laser includes a laser diode emitter with a tunable absorber to achieve a broadened emissions spectrum. In another example, the broad-spectrum laser includes a laser diode emitter array having plural individual emitters with different spectral peaks.

A broad-spectrum laser for use in a MEMS laser scanning display device is provided. In one example, the broad-spectrum laser includes a laser diode emitter with plural quantum wells each having a different spectral peak. In another example, the broad-spectrum laser includes a laser diode emitter with a tunable absorber to achieve a broadened emissions spectrum. In another example, the broad-spectrum laser includes a laser diode emitter array having plural individual emitters with different spectral peaks.