A tunable solid state laser device are described comprising a semiconductor based gain chip and a silicon photonic filter chip with tuning capability. The silicon photonic filter chip can comprises an input-output silicon waveguide, at least two ring resonators formed with silicon waveguides, one or more connecting silicon waveguides interfacing with the ring resonators, a separate heater associated with each ring resonator, a temperature sensor configured to measure the chip temperature, and a controller connected to the temperature sensor and the separate heaters and programmed with a feedback loop to maintain the filter temperature to provide the tuned frequency. The one or more connecting silicon waveguides are configured to redirect light resonant with each of the at least two ring resonators back through the input-output silicon waveguide. Corresponding methods are described for the control of the laser frequency. Improved structures of the SiPho multiple filter chip involve a Zagnac interferometer.

A tunable laser for a transceiver includes a silicon photonics substrate, first and second patterned regions each being defined in the substrate a step lower than a flat surface region of the substrate, first and second laser diode chips arranged in the first and second patterned regions, the patterned regions being configured to align the gain regions of the first and second laser diode chips with integrated couplers formed in the substrate adjacent to the first and second patterned regions to facilitate flip-bonding the first and second laser diode chips within the patterned regions, and a tuning filter coupled to the first laser diode chip and the second laser diode chip via the integrated couplers. The tuning filter is configured to receive laser light from each of the first and second laser diode chips and generate a laser output having a gain determined by each of the gain regions.

A monolithic InP-based PIC having a first photonic assembly that has a first optical splitter-combiner unit having a first end part that is optically connected with a first optical waveguide and a second end part that is optically connected with a first main photonic circuit and a first auxiliary photonic circuit. The first auxiliary photonic circuit has a first laser unit, and a first SOA. The first SOA is configurable to be in a first operational state in which the first SOA allows optical communication between the first laser unit and the first optical splitter-combiner unit, or a second operational state in which the first SOA prevents optical communication between the first laser unit and the first optical splitter-combiner unit. An opto-electronic system including the PIC.

A laser device (1) includes: a branch waveguide (23) configured to split light propagating from an optical amplifier (10) into a plurality of light beams and output the plurality of light beams; a multi-core waveguide (27) including a plurality of waveguide cores (24 to 26) configured to carry the plurality of light beams input from the branch waveguide (23); and a light reflector (31) optically coupled to a light input/output end of the multi-core waveguide (27). The waveguide cores (24 to 26) are configured to extend along the same direction, and placed in proximity to one another to enable optical coupling between adjacent waveguide cores of the waveguide cores (24 to 26).

This application describes a wavelength-tunable laser apparatus, which reduces complexity of wavelength tuning of a laser. The laser includes a reflective gain unit, an optical phase shifter, a coupler, and a passive filter unit array. Furthermore, an output port of the reflective gain unit is connected to an input port of the optical phase shifter, an output port of the optical phase shifter is connected to an input port of the coupler, a first output port of the coupler is connected to an input port of the passive filter unit array, and a second output port of the coupler is an output port of the laser. The passive filter unit array includes a plurality of passive filter units, where any two of the plurality of passive filter units have different wavelength tuning ranges, and each filter unit has a linearly tunable wavelength.

The semiconductor laser device comprises a laser part, a waveguide for propagating laser light emitted by the laser part, and a photodetector for detecting the laser light which are formed on the same semiconductor substrate. The photodetector includes a p-type contact layer which is formed above the side of the waveguide on the side opposite to the semiconductor substrate and is connected to an anode electrode, an n-type contact layer connected to a cathode electrode, and an undoped layer formed between the p-type contact layer and the n-type contact layer. The undoped layer and the n-type contact layer in the photodetector include a main light receiving part disposed above the waveguide so as to encompass the waveguide, and an enlarged part disposed so as not to encompass the waveguide while connected to the main light receiving part.

Various designs of semiconductor lasers may comprise a waveguide having a front region that is configured to support a plurality of transverse laser cavity modes and a rear region that support only one transverse laser cavity mode. These front and rear regions may be disposed between front and rear reflectors and may provide optical gain. Some such designs may be useful for providing higher power single mode semiconductor lasers.

Embodiments include apparatuses, methods, and systems including a laser device having a 1×3 MMI coupler within a semiconductor layer. A front arm is coupled to the MMI coupler and terminated by a front reflector. In addition, a coarse tuning arm is coupled to the MMI coupler and terminated by a first back reflector for coarse wavelength tuning, a fine tuning arm is coupled to the MMI coupler and terminated by a second back reflector for fine wavelength tuning, and a SMSR and power tuning arm is coupled to the MMI coupler and terminated by a third back reflector. A gain region is above the front arm and above the semiconductor layer. Other embodiments may also be described and claimed.

A QCL may include a substrate, and a semiconductor layer adjacent the substrate. The semiconductor layer may define branch active regions, and a stem region coupled to output ends of the branch active regions. Each branch active region may have a number of stages less than 30.

A semiconductor laser source including a Mach-Zehnder interferometer including first and second arms. Each of these arms being divided into a plurality of consecutive sections. The first and second arms each include a gain-generating section forming first and second gain-generating waveguides, respectively. The laser source includes power sources able to deliver currents through the gain-generating waveguides such that the following condition is met: $\underset{n=1}{\overset{N_2}{.Math.}}{L}_{2,n}{\mathrm{neff}}_{2,n}-\underset{n=1}{\overset{N_1}{.Math.}}{L}_{1,n}{\mathrm{neff}}_{1,n}=k_f{\lambda }_{\mathrm{Si}}$
where: k.sub.f is a preset integer number higher than or equal to 1, N.sub.1 and N.sub.2 are the numbers of sections in the first and second arms, respectively, L.sub.1,n and L.sub.2,n are the lengths of the nth sections of the first and second arms, respectively, neff.sub.1,n and neff.sub.2,n are the effective indices of the nth sections of the first and second arms, respectively.