Abstract: By determining an alignment point for a photonic element in a substrate of a given material; applying, via a laser aligned with the photonic element according to the alignment point, an etching pattern to the photonic element to produce a patterned region and an un-patterned region in the photonic element, wherein applying the etching pattern alters a chemical bond in the given material for the patterned region of the photonic element that increases a reactivity of the given material to an etchant relative to a reactivity of the un-patterned region, and wherein the patterned region defines an engagement feature in the un-patterned region that is configured to engage with a mating feature on a Photonic Integrated Circuit (PIC); and removing the patterned region from the photonic element via the etchant, various systems and methods may make use of laser patterning in optical components to enable alignment of optics to chips.

Abstract: A submount assembly comprises a first substrate having a first surface and an opposing second surface, wherein a plurality of first grooves are formed into the first substrate from the first surface. Each first groove is dimensioned to receive a portion of a respective optical fiber of a plurality of optical fibers, and to arrange the optical fiber with a predetermined first height relative to the first surface. The submount assembly further comprises a plurality of first conductive traces on a side of the first substrate corresponding to the first surface, and a semiconductor laser contacted with the first conductive traces. The semiconductor laser has a predetermined second height relative to the first surface. The submount assembly further comprises a plurality of second conductive traces at the second surface and a plurality of first vias extending through the first substrate from the first conductive traces to the second conductive traces.

Abstract: The embodiments herein describe an optical transmitter that integrates a SCOWA into a photonic chip that includes a modulator. The embodiments herein place the SCOWA between the laser and the modulator. To accommodate the large mode size of the waveguide in the SCOWA, the photonic chip includes a pair of spot size converters coupled to the input and output of the SCOWA. Rather than amplifying a modulated signal as is typical with an inline amplifier, the SCOWA amplifies a continuous wave (CW) optical signal generated by the laser which introduces less noise and improves the OSNR of the transmitter.

Abstract: A submount assembly comprises a first substrate having a first surface and an opposing second surface, wherein a plurality of first grooves are formed into the first substrate from the first surface. Each first groove is dimensioned to receive a portion of a respective optical fiber of a plurality of optical fibers, and to arrange the optical fiber with a predetermined first height relative to the first surface. The submount assembly further comprises a plurality of first conductive traces on a side of the first substrate corresponding to the first surface, and a semiconductor laser contacted with the first conductive traces. The semiconductor laser has a predetermined second height relative to the first surface. The submount assembly further comprises a plurality of second conductive traces at the second surface and a plurality of first vias extending through the first substrate from the first conductive traces to the second conductive traces.

Abstract: Embodiments herein describe a fiber array unit (FAU) configured to optically couple a photonic chip with a plurality of optical fibers. Epoxy can be used to bond the FAU to the photonic chip. However, curing the epoxy between the FAU and the photonic chip is difficult. As such, the FAU can include one or more optical windows etched into or completely through a non-transparent layer that overlap the epoxy disposed on the photonic chip. UV radiation can be emitted through the optical windows to cure the underlying epoxy. In one example, the windows can also be used for dispensing epoxy. In addition to the optical windows, the FAU can include alignment protrusions (e.g., frustums) which mate or interlock with respective alignment receivers in the photonic chip. Doing so may facilitate passive alignment of the optical fibers in the FAU to an optical interface in the photonic chip.

Abstract: A method comprises bonding a first surface of an interposer wafer with a first exterior surface of a photonic wafer assembly. The photonic wafer assembly comprises one or more optical devices coupled with one or more metal layers and with one or more first optical waveguides. The method further comprises forming, from a second surface opposite the first surface, a plurality of first conductive vias extending at least partway through the interposer wafer and coupled with the one or more metal layers. The method further comprises forming, at the second surface, a plurality of first conductive pads coupled with the plurality of first conductive vias. The method further comprises forming one or more second conductive pads coupled with the one or more metal layers. The one or more second conductive pads are accessible at a second exterior surface of the photonic wafer assembly opposite the first exterior surface.

Abstract: The disclosed embodiments relate to the design of a hybrid laser comprising a shared ring mirror coupled to a pair of buses by a 3 dB coupler (also referred to as a “symmetric splitter”), which is described in more detail below. Each bus is also coupled to an array of ring filters, wherein each ring filter couples an associated reflective silicon optical amplifier (RSOA) to the shared ring mirror and in doing so forms a Verniered ring pair with the shared ring mirror. The resulting system provides a comb source with redundant channels that can provide individual outputs or a shared output. This hybrid laser provides a significant improvement over existing comb-based lasers by providing redundancy for at least one laser channel.

Abstract: An optical source includes semiconductor optical amplifiers, with a semiconductor other than silicon, which provide an optical gain medium. Moreover, a photonic chip in the optical source, which is optically coupled to the semiconductor optical amplifiers, includes ring resonators that selectively pass corresponding optical signals having carrier wavelengths provided by the semiconductor optical amplifiers, where a given ring resonator and a reflector on one of the semiconductor optical amplifier defines an optical cavity, and the ring resonators have different radii with associated resonance wavelengths corresponding to the carrier wavelengths.

Abstract: A reflectivity test circuit is described. The reflectivity test circuit includes a symmetric structure that cancels errors in the reflectivity measurements. In particular, the reflectivity test circuit includes an optical waveguide that is optically coupled to two optical ports and two optical couplers. The optical couplers are optically coupled to adjacent optical waveguides, at least one of which is optically coupled to a third optical port and the mirror. Moreover, a length of the optical waveguide is chosen to match the round-trip optical path length in at least the one of the adjacent optical waveguides. During operation, control logic determines the reflectivity of the mirror based at least on a ratio of an optical power measured on one of the two optical ports to an input optical power on the third optical port.

Abstract: An integrated laser that provides multiple outputs includes a reflective silicon optical amplifier (RSOA) having a reflective end with a reflective coating and an interface end. It also includes an optical waveguide optically coupled to the RSOA. A distributed-Bragg-reflector (DBR) ring resonator is also optically coupled to the optical waveguide, wherein the DBR ring resonator partially reflects a wavelength of the optical signal from the optical waveguide, thereby causing balanced light to flow in clockwise and counter-clockwise directions inside the DBR ring resonator. The integrated laser additionally includes an output waveguide having 2*N ends that function as two outputs, wherein the output waveguide is optically coupled to the DBR ring resonator, which causes balanced light to flow in two directions in the output waveguide, thereby causing the 2*N outputs to provide balanced power.

Abstract: The disclosed embodiments relate to the design of a hybrid laser comprising a shared ring mirror coupled to a pair of buses by a 3 dB coupler (also referred to as a “symmetric splitter”), which is described in more detail below. Each bus is also coupled to an array of ring filters, wherein each ring filter couples an associated reflective silicon optical amplifier (RSOA) to the shared ring mirror and in doing so forms a Verniered ring pair with the shared ring mirror. The resulting system provides a comb source with redundant channels that can provide individual outputs or a shared output. This hybrid laser provides a significant improvement over existing comb-based lasers by providing redundancy for at least one laser channel.

Abstract: The disclosed embodiments improve on the design of existing hybrid ring lasers by enabling a redundancy of one of the least reliable components, the III-V reflective semiconductor optical amplifier (RSOA). This allows a spare RSOA to be used to replace a failed RSOA while using the same ring mirror as the wavelength selective filter, thus reducing link down time, and eliminating the need for additional switching or multiplexing elements which add excess loss and require additional power. The result is a more reliable transmitter enabling greater scale in networking systems. In addition, this facilitates a widely tunable laser with the same outputs by utilizing two gain media comprised of different bandgap active material. Finally, multiple correlated wavelengths can be emitted from this device with two different gain materials using the same ring mirror element as reference.

Abstract: An integrated laser that provides multiple outputs includes a reflective silicon optical amplifier (RSOA) having a reflective end with a reflective coating and an interface end. It also includes an optical waveguide optically coupled to the RSOA. A distributed-Bragg-reflector (DBR) ring resonator is also optically coupled to the optical waveguide, wherein the DBR ring resonator partially reflects a wavelength of the optical signal from the optical waveguide, thereby causing balanced light to flow in clockwise and counter-clockwise directions inside the DBR ring resonator. The integrated laser additionally includes an output waveguide having 2*N ends that function as two outputs, wherein the output waveguide is optically coupled to the DBR ring resonator, which causes balanced light to flow in two directions in the output waveguide, thereby causing the 2*N outputs to provide balanced power.

Abstract: The disclosed embodiments improve on the design of existing hybrid ring lasers by enabling a redundancy of one of the least reliable components, the III-V reflective semiconductor optical amplifier (RSOA). This allows a spare RSOA to be used to replace a failed RSOA while using the same ring mirror as the wavelength selective filter, thus reducing link down time, and eliminating the need for additional switching or multiplexing elements which add excess loss and require additional power. The result is a more reliable transmitter enabling greater scale in networking systems. In addition, this facilitates a widely tunable laser with the same outputs by utilizing two gain media comprised of different bandgap active material. Finally, multiple correlated wavelengths can be emitted from this device with two different gain materials using the same ring mirror element as reference.

Abstract: An optical source includes semiconductor optical amplifiers, with a semiconductor other than silicon, which provide an optical gain medium. Moreover, a photonic chip in the optical source, which is optically coupled to the semiconductor optical amplifiers, includes ring resonators that selectively pass corresponding optical signals having carrier wavelengths provided by the semiconductor optical amplifiers, where a given ring resonator and a reflector on one of the semiconductor optical amplifier defines an optical cavity, and the ring resonators have different radii with associated resonance wavelengths corresponding to the carrier wavelengths.

Abstract: An integrated circuit includes optical waveguides defined in a semiconductor layer, and uses removable optical taps to allow for in-process characterization and trimming. These optical waveguides may be trimmed during fabrication of the integrated circuit to improve performance. Note that the trimming may modify indexes of refraction of portions of the optical waveguides or may involve a more invasive process. Moreover, the trimming may exclude or may not involve the use of a polymer and/or the carrier wavelengths at a given temperature may be stable as a function of time. The trimming process may use removable optical taps for external feedback to determine the amount of change required. These optical taps may be formed either in the semiconductor layer or the cladding layer, and they may be disabled with negligible impact to device performance via alterations to the cladding layer after the completion of trimming.

Abstract: A dual-ring-modulated laser includes a gain medium having a reflective end coupled to a gain-medium reflector and an output end coupled to a reflector circuit to form a lasing cavity. This reflector circuit comprises: a first ring modulator; a second ring modulator; and a shared waveguide that optically couples the first and second ring modulators. The first and second ring modulators have resonance peaks, which are tuned to have an alignment separation from each other. During operation, the first and second ring modulators are driven in opposing directions based on the same electrical input signal, so the resonance peaks of the first and second ring modulators shift wavelengths in the opposing directions during modulation. The modulation shift for each of the resonance peaks equals the alignment separation, so the resonance peaks interchange positions during modulation to cancel out reflectivity changes in the lasing cavity caused by the modulation.

Abstract: A laser includes a reflective gain medium (RGM) comprising an optical gain material coupled with an associated reflector. The RGM is coupled to a spot-size converter (SSC), which optically couples the RGM to an optical reflector through a silicon waveguide. The SSC converts an optical mode-field size of the RGM to an optical mode-field size of the silicon waveguide. A negative thermo-optic coefficient (NTOC) waveguide is fabricated on top of the SSC. In this way, an optical signal, which originates from the RGM, passes into the SSC, is coupled into the NTOC waveguide, passes through the NTOC waveguide, and is coupled back into the SSC before passing into the silicon waveguide. During operation, the RGM, the spot-size converter, the NTOC waveguide, the silicon waveguide and the silicon mirror collectively form a lasing cavity for the athermal laser. Finally, a laser output is optically coupled to the lasing cavity.

Abstract: A laser includes a reflective gain medium (RGM) comprising an optical gain material coupled with an associated reflector. The RGM is coupled to a spot-size converter (SSC), which optically couples the RGM to an optical reflector through a silicon waveguide. The SSC converts an optical mode-field size of the RGM to an optical mode-field size of the silicon waveguide. A negative thermo-optic coefficient (NTOC) waveguide is fabricated on top of the SSC. In this way, an optical signal, which originates from the RGM, passes into the SSC, is coupled into the NTOC waveguide, passes through the NTOC waveguide, and is coupled back into the SSC before passing into the silicon waveguide. During operation, the RGM, the spot-size converter, the NTOC waveguide, the silicon waveguide and the silicon mirror collectively form a lasing cavity for the athermal laser. Finally, a laser output is optically coupled to the lasing cavity.

Abstract: A reflectivity test circuit is described. The reflectivity test circuit includes a symmetric structure that cancels errors in the reflectivity measurements. In particular, the reflectivity test circuit includes an optical waveguide that is optically coupled to two optical ports and two optical couplers. The optical couplers are optically coupled to adjacent optical waveguides, at least one of which is optically coupled to a third optical port and the mirror. Moreover, a length of the optical waveguide is chosen to match the round-trip optical path length in at least the one of the adjacent optical waveguides. During operation, control logic determines the reflectivity of the mirror based at least on a ratio of an optical power measured on one of the two optical ports to an input optical power on the third optical port.