A distributed feedback plus reflection (DFB+R) laser includes an active section, a passive section, a low reflection (LR) mirror, and an etalon. The active section includes a distributed feedback (DFB) grating and is configured to operate in a lasing mode. The passive section is coupled end to end with the active section. The LR mirror is formed on or in the passive section. The etalon includes a portion of the DFB grating, the passive section, and the LR mirror. The lasing mode of the active section is aligned to a long wavelength edge of a reflection peak of the etalon.

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 semiconductor laser comprising a single mode laser cavity having a stack of semiconducting layers defining a transversal p-n junction is provided. A plurality of electrodes are coupled to corresponding sections of the laser cavity along the longitudinal light propagation direction, each corresponding section defining one of an amplification section or a modulation section. One or more DC sources are coupled to the electrodes associated with the amplification sections to forward-bias the p-n junction above transparency, so as to provide gain in the associated amplification sections. One or more modulation signal sources are coupled to the electrodes associated with the modulation sections, and apply a modulation signal across the p-n junction below transparency, the modulation signal providing a modulation of an output optical frequency of the semiconductor laser. Each modulation section is operated in photovoltaic mode.

A beam positioner for deflecting a beam path, along which a diffracted beam of linearly polarized laser light is propagatable, within a two-dimensional scan field, the beam positioner includes a first acousto-optic deflectors (AOD) to deflect the beam path within a first one-dimensional scan field extending along a first axis of the two-dimensional scan field, a second AOD to deflect the beam path within a second one-dimensional scan field extending along a second axis of the two-dimensional scan field, a phase retarder arranged between the first AOD and the second AOD and within the beam path along which the beam of laser light is propagatable from the first AOD and a mirror arranged between the first AOD and the second AOD and within the beam path along which the beam of laser light is propagatable from the first AOD.

A two-kappa DBR laser includes an active section, a HR mirror, a first DBR section, and a second DBR section. The HR mirror is coupled to a rear of the active section. The first DBR section is coupled to a front of the active section, the first DBR section having a first DBR grating with a first kappa κ1. The second DBR section is coupled to a front of the first DBR section such that the first DBR section is positioned between the active section and the second DBR section. The second DBR section has a second DBR grating with a second kappa κ2 less than the first kappa κ1. The two-kappa DBR laser is configured to operate in a lasing mode and has a DBR reflection profile that includes a DBR reflection peak. The lasing mode is aligned to a long wavelength edge of the DBR reflection peak.

An on-chip wavelength locker may include an optical waveguide splitter to split an input optical signal received from a laser. The on-chip wavelength locker may include a plurality of integrated periodic optical elements, each to receive a respective portion of the input optical signal after splitting of the input optical signal by the optical waveguide splitter, and provide, based on the respective portion of the input optical signal, a respective periodic output optical signal of a plurality of periodic output optical signals. Each periodic output optical signal, of the plurality of periodic output optical signals, may be phase shifted with respect to other periodic output optical signals of the plurality of periodic output optical signals. The on-chip wavelength locker may include a plurality of integrated photodiodes to receive the plurality of periodic output optical signals in association with wavelength locking the laser.

The grating layer of a surface emitting laser is divided into a first grating region and a second grating region along a horizontal direction. The second grating region is located at a middle area of the grating layer, while the first grating region is located in an outer peripheral area of the grating layer. Each of the first and second grating regions comprises a plurality of micro-grating structures. The grating period of the micro-grating structures in the first grating region is in accordance with the following mathematical formula: $.Math.=m\frac{\lambda }{2*n_{\mathrm{eff}}};$
in addition, the grating period of the micro-grating structures in the second grating region is in accordance with the following mathematical formula: $.Math.=o\frac{\lambda }{2*n_{\mathrm{eff}}}.$
Wherein, Λ is the length of grating period, λ is the wavelength of the laser light, n.sub.eff is the equivalent refractive index of semiconductor waveguide, m=1, and o=2. The first grating region is a first-order grating region, and the second grating region is a second-order grating region, so as to form a hybrid grating structure in the grating layer. The surface emitting laser emits laser light perpendicularly from a light-emitting surface defined by the second grating region.

There is provided a configuration which includes: a burying layer which has a current narrowing window where portions protruding onto a top part of a ridge stripe are opposed to each other with an interval therebetween narrower than a width of the top part; and a diffraction grating in which a λ/4 phase shifter is placed at an intermediate portion in a light traveling direction; wherein a sectional shape of the current narrowing window varies depending on a position in the light traveling direction so that, at a region where the λ/4 phase shifter is placed, a resistance of a current path from a second cladding layer to a first cladding layer through the current narrowing window is minimum.

The grating layer of a surface emitting laser is divided into a first grating region and a second grating region along a horizontal direction. The second grating region is located at a middle area of the grating layer, while the first grating region is located in an outer peripheral area of the grating layer. Each of the first and second grating regions comprises a plurality of micro-grating structures. The grating period of the micro-grating structures in the first grating region is in accordance with the following mathematical formula:

[00001]$\text{Λ}=\text{m}\frac{\text{λ}}{2\ast {\text{n}}_{eff}};$

in addition, the grating period of the micro-grating structures in the second grating region is in accordance with the following mathematical formula:

[00002]$\text{Λ}=\text{O}\frac{\text{λ}}{2\ast {\text{n}}_{eff}}.$

Wherein, Λ is the length of grating period, λ is the wavelength of the laser light, n.sub.eff is the equivalent refractive index of semiconductor waveguide, m=1, and o=2. The first grating region is a first-order grating region, and the second grating region is a second-order grating region, so as to form a hybrid grating structure in the grating layer. The surface emitting laser emits laser light perpendicularly from a light-emitting surface defined by the second grating region.

A hybrid distributed feedback (DFB) laser formed from III-V and silicon materials can include a grating in the III-V material to provide optical feedback for mode selection. The grating can include a shift feature in a middle or other parts of the grating to change light output from the gain region. The grating can be a top-surface grating or regrowth can be applied to the III-V structure, which can then be bonded to a silicon structure to couple DFB laser light from the III-V structure to one or more silicon waveguides in the silicon structure.