A laser chip is described which comprises a plurality of gain areas. Each gain area comprises a ridge waveguide and a wavelength locking element, where the wavelength locking element in a gain area defines the output wavelength characteristics of visible light emitted from that gain area and adjacent gain areas comprise different wavelength locking elements.

Improved systems and methods for externally modulating a laser. Such systems may comprise a laser section and a modulator section made of an active material that selectively absorbs light from the laser section, where the operating wavelength of the laser is near the exciton absorption peak of the active material of the EAM.

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.

A semiconductor optical integrated element of the present disclosure includes: a laser diode portion which is provided on one end side above a substrate, has a first optical waveguide, and emits a laser beam; a modulator portion which is provided on another end side, has a second optical waveguide, and modulates the laser beam; a separation region provided between the laser diode portion and the modulator portion; and a pair of grooves provided on both sides along the first optical waveguide and the second optical waveguide. The second optical waveguide in the separation region and the second optical waveguide in a part on the separation region side in the modulator portion have a buried structure, and the second optical waveguide in a remaining part in the modulator portion has a high-mesa-ridge structure.

An electroabsorption modulated laser having a first face, a second face, an optical cavity and an active region, the optical cavity being defined by a semiconductor substrate and having a length extending between the first face and the second face, and the active region being configured for injection of charge into the cavity and having effective bandgap energies at respective distances along the length of the cavity, the electroabsorption modulated laser comprising a first modulator section extending between a first position and a second position and comprising a first part of the active region, and a second modulator section extending between the second position and a third position and comprising a second part of the active region, wherein the bandgap energy of the first part of the active region adjacent the first position is higher than the bandgap energy adjacent the second position.

This disclosure relates to a spatial light modulator, etc., the spatial light modulator being capable of dynamically controlling the phase distribution of light, and provided with a structure having a smaller pixel arrangement period and suitable for high-speed operation. The spatial light modulator includes a substrate. The substrate has a front surface, a back surface, and through-holes arranged one-dimensionally or two-dimensionally and penetrating between the front surface and the back surface. The spatial light modulator further includes layered structures each covering the inner walls of the through-holes. Each layered structure includes a first electroconductive layer on the inner wall, a dielectric layer on the first electroconductive layer and having optical transparency, and a second electroconductive layer on the dielectric layer and having optical transparency. At least one of the first and second electroconductive layers is electrically isolated for each group including one or more through-holes.

There is provided a method of operating a laser. The method comprises receiving a target power and calculating an operating power of a lasing module of the laser. The operating power may be calculated based on the target power and a minimum lasing power of the lasing module. The method also comprises determining an operating current for the lasing module based on the operating power, and driving the lasing module at the operating current to produce an output light having the operating power. In addition, the method comprises providing the output light to an optical modulator of the laser, and operating the optical modulator to modulate the output light to have an output power corresponding to the target power.

A first conductive pattern (13) is provided on an upper surface of the submount (7). A GND pattern (9) is provided on a lower surface of the submount (7). A lower surface electrode (21) of a capacitor (3) is bonded to the first conductive pattern (13) with solder (22). An upper surface electrode (23) of the capacitor (3) is connected to a light emitting device (2). A terminating resistor (4) is connected to the first conductive pattern (13). The first conductive pattern (13) has a protruding portion (25) which protrudes outside from the capacitor (3) in planar view. A width of the protruding portion (25) is narrower than a width of the capacitor (3).

In the present disclosure, in an EADFB laser in which an SOA has been integrated, a new configuration in which a problem of deterioration of optical waveform quality and insufficient optical output is solved or mitigated while taking advantage of characteristics that the same layer structure can be used and a manufacturing process can be simplified is shown. In an optical transmitter of the present disclosure, a waveguide structure having different core widths (waveguide widths) is adopted while using the same layer structure for a DFB laser and the SOA. Waveguides with different core widths are adopted so that a problem of insufficient saturated optical output or waveform deterioration due to a pattern effect is solved and mitigated. A passive waveguide region having a tapered shape is introduced in a part between an EA modulator and the SOA so that a waveguide width is continuously changed.

Various semiconductor laser and optical amplifier designs and injection current control methods are disclosed that enable tailoring a distribution of the injection current along an active waveguide of the laser or the optical amplifier. Such configurations can be used to reduce longitudinal current crowding along the active waveguide of the laser or the optical amplifier. The electrodes and/or one or more layers of the laser or the optical amplifier may be segmented to provide a tailored longitudinal injection current distribution.