A monolithic integrated semiconductor random laser comprising substrate, lower confinement layer on the substrate, active layer on the lower confinement layer, upper confinement layer on the active layer, strip-shaped waveguide layer longitudinally made in middle of the upper confinement layer, P.sup.+ electrode layer divided into two segments and made on the waveguide layer and N.sup.+ electrode layer on a back face of the lower confinement layer, wherein the two segments correspond respectively to gain region and random feedback region. The random feedback region uses a doped waveguide to randomly feedback light emitted by the gain region and then generates random laser which is random in frequency and intensity. Further, the semiconductor laser is light, small, stable in performance and strong in integration.

A system includes a waveguide and an edge-emitting laser. The edge-emitting laser is configured to lase coherent light into the waveguide. The edge-emitting laser includes an optical cavity having an active gain section and a passive section. The active gain section is configured to amplify an optical power of light reflecting within the optical cavity. The passive section increases a functional length of the optical cavity such that a total length of the optical cavity reduces fringe interference of the coherent light propagating through the waveguide.

Example wavelength tunable lasers are described. One example wavelength tunable laser includes a reflective semiconductor optical amplifier, three couplers, and at least two microring resonators. The reflective semiconductor optical amplifier is connected to one port of the first coupler. Some of the at least two microring resonators are arranged between another port of the first coupler and one port of the second coupler, the others of the at least two microring resonators are arranged between a third port of the first coupler and a second port of the second coupler, and a third port and a fourth port of the second coupler are connected to two ports of the third coupler.

A semiconductor device includes a substrate, a semiconductor laser part formed on the substrate and having an active layer with an uniform composition and a first ridge structure, and an adjacent part formed on the substrate, having a core layer with an uniform composition and a second ridge structure, and being an optical modulator or an optical waveguide which is in contact with the semiconductor laser part, wherein the first ridge structure is largest in width at a first contact part which is in contact with the second ridge structure, and the second ridge structure is largest in width at a second contact part which is in contact with the first ridge structure.

A system includes a waveguide and an edge-emitting laser. The edge-emitting laser is configured to lase coherent light into the waveguide. The edge-emitting laser includes an optical cavity having an active gain section and a passive section. The active gain section is configured to amplify an optical power of light reflecting within the optical cavity. The passive section increases a functional length of the optical cavity such that a total length of the optical cavity reduces fringe interference of the coherent light propagating through the waveguide.

An on-chip laser includes a gain portion, a mirror in communication with the gain portion, a waveguide in communication with the gain portion, and a resonator optically coupled to the waveguide at an optical coupling. The resonator has a circular shape. The waveguide and the resonator are separate from the gain portion.

In an example embodiment, a system includes a first grating-coupled laser (GCL) that includes a first laser cavity optically coupled to a first transmit grating coupler configured to redirect horizontally-propagating first light, received from the first laser cavity, vertically downward and out of the first GCL. The system also includes a second GCL that includes a second laser cavity optically coupled to a second transmit grating coupler configured to transmit second light vertically downward and out of the second GCL. The system also includes a photonic integrated circuit (PIC) that includes a first receive grating coupler optically coupled to a first waveguide and configured to receive the first light and couple the first light into the first waveguide. The PIC also includes a second receive grating coupler optically coupled to a second waveguide and configured to receive the second light and couple the second light into the second waveguide.

A split electrode vertical cavity optical device includes an n-type ohmic contact layer, first through fifth ion implant regions, cathode and anode electrodes, first and second injector terminals, and p and n type modulation doped quantum well structures. The cathode electrode and the first and second ion implant regions are formed on the n-type ohmic contact layer. The third ion implant region is formed on the first ion implant region and contacts the p-type modulation doped QW structure. The fourth ion implant region encompasses the n-type modulation doped QW structure. The first and second injector terminals are formed on the third and fourth ion implant regions, respectively. The fifth ion implant region is formed above the n-type modulation doped QW structure and the anode electrode is formed above the fifth ion implant region.

Provided is an external cavity laser (ECL) including a vertical cavity surface emitting laser (VCSEL)-Distributed Bragg Reflector (DBR) type light emitting unit configured to receive a current and emit light, and including a DBR function layer and an active layer for a quantum well formed on one side of this DBR function layer, and an optical circuit unit including a light guide in which one end surface is installed to face an active layer at one side of the active layer, light generated from the active layer is received and guided, and an optical axis is formed vertically to an active layer plane, a reflection pattern that is formed at one side of the light guide so as to receive light output from the other end of the light guide to reflect the light again to the light guide, and an external layer for surrounding the light guide and the reflection pattern, wherein the VCSEL-DBR type light emitting unit and the optical circuit unit are mutually coupled to each other. An optical coupling efficiency in the ECL may be raised by improving an inefficient optical coupling issue including alignment, reflection, and the like in a coupling part of a gain element and a silicon waveguide.

An optical apparatus comprises a semiconductor substrate, and a supermode filtering waveguide (SFW) emitter disposed on the semiconductor substrate. The SFW emitter comprises a first optical waveguide, a spacer layer, and a second optical waveguide spaced apart from the first optical waveguide by the spacer layer. The second optical waveguide is evanescently coupled with the first optical waveguide and is configured, in conjunction with the first waveguide, to selectively propagate only a first mode of a plurality of optical modes. The SFW emitter further comprises an optically active region disposed in one of the first optical waveguide and the second optical waveguide.