Abstract: Aspects of the present disclosure are directed to a photonic integrated circuit (PIC) having a resistivity-engineered substrate to suppress radio-frequency (RF) common-mode signals. In some embodiments, a semiconductor substrate is provided that comprises two portions having different levels of resistivity to provide both suppression of common mode signals, and reduction of RF absorption loss for non-common mode RF signals. In such embodiments, a bottom portion of the semiconductor substrate has a low resistivity to suppress common mode via RF absorption, while a top portion of the semiconductor substrate that is adjacent to conductors in the IC has a high resistivity to reduce RF loss.

Abstract: Aspects of the present disclosure are directed to a photonic integrated circuit (PIC) having a resistivity-engineered substrate to suppress radio-frequency (RF) common-mode signals. In some embodiments, a semiconductor substrate is provided that comprises two portions having different levels of resistivity to provide both suppression of common mode signals, and reduction of RF absorption loss for non-common mode RF signals. In such embodiments, a bottom portion of the semiconductor substrate has a low resistivity to suppress common mode via RF absorption, while a top portion of the semiconductor substrate that is adjacent to conductors in the IC has a high resistivity to reduce RF loss.

Abstract: Aspects of the present disclosure are directed to a photonic integrated circuit (PIC) having a resistivity-engineered substrate to suppress radio-frequency (RF) common-mode signals. In some embodiments, a semiconductor substrate is provided that comprises two portions having different levels of resistivity to provide both suppression of common mode signals, and reduction of RF absorption loss for non-common mode RF signals. In such embodiments, a bottom portion of the semiconductor substrate has a low resistivity to suppress common mode via RF absorption, while a top portion of the semiconductor substrate that is adjacent to conductors in the IC has a high resistivity to reduce RF loss.

Abstract: A tunable semiconductor laser incorporates a light generating structure in which light is generated and amplified by stimulated emission. The generated light is evanescently coupled into a first resonator of a first resonant optical reflector where the light is reflected back and forth between two end mirrors. A portion of this light, which is characterized by a series of resonant wavelengths, is evanescently coupled back into the light generating structure. One or more of the resonant wavelengths can be changed by modifying an optical path length of the first resonator. The tunable semiconductor laser further includes a second resonant optical reflector having a second resonator. The second resonator interacts with the light generating structure in a manner similar to the first resonator. A desired beat wavelength can be obtained by modifying the optical path length in one or both resonators.

Abstract: A wavelength division multiplexer utilizes an optical source in the form of at least two separate laser array components, each laser array component including a group of laser diodes operating at wavelengths that are spaced by a multiple of the pre-defined channel spacing of the multiplexer. This optical source thus generates a plurality of non-sequential optical signals that need to be re-ordered at some point along the signal path so that all of the signals are multiplexed onto a single output signal path. The multiplexer utilizes an arrayed waveguide grating (AWG) to combine the various optical signals, with a specialized apparatus for re-ordering the non-sequential wavelengths of the propagating plurality of N optical signals disposed either at the input or output of the AWG.

Abstract: The present invention provides an optical device and a method of manufacture thereof. In one embodiment, the method of manufacturing the optical device may include isolating an end of a first layer from a cladding layer located over a mesa structure that has been formed from a substrate. The end of the first layer may be isolated from the cladding layer by encapsulating the end between second and third layers located adjacent the mesa structure.

Abstract: A process evaluates an aging property of a distributed Bragg reflector (DBR) laser. The process includes illuminating a Bragg grating of the distributed Bragg reflector (DBR) laser with light while the DBR laser is both supplied a tuning current and not lasing. The process also includes performing an action to the DBR laser responsive to a wavelength of a Bragg peak in a portion of the light reflected by the Bragg grating and a value of the tuning current supplied during the illuminating.

Abstract: The present invention provides an optical device and a method of manufacture thereof. In one embodiment, the method of manufacturing the optical device may include isolating an end of a first layer from a cladding layer located over a mesa structure that has been formed from a substrate. The end of the first layer may be isolated from the cladding layer by encapsulating the end between second and third layers located adjacent the mesa structure.

Abstract: The invention is a semiconductor optical device and a method of manufacture. The device includes a first waveguide having an edge, and a second waveguide adjacent to at least a portion of the first waveguide including the edge so that light is coupled from the first to the second waveguide. The second waveguide has a modal index which is essentially constant at least at the edge of the first waveguide. The method includes forming at least the second waveguide by Selective Area Growth (SAG) using oxide pads of a particular geometry to achieve the essentially constant modal index. In one embodiment, the device is an expanded beam laser with an expander portion which is less than 300 microns.

Abstract: The invention in one aspect is an optical modulator which includes a waveguide region of semiconductor material. In order to achieve a gradual, essentially linear transfer function, the bandgap of the waveguide region is graded along the direction of light propogation or perpendicular thereto. In accordance with another aspect, the invention is an electroabsorption modulated laser where the portion of the waveguide region defining the modulator has a graded bandgap. In accordance with a method aspect, the waveguide region of the modulator is grown using a mask having a varying width to achieve the graded bandgap.

Abstract: A hybrid integrated optical transmitter comprising a wavelength selectable laser (WSL) source coupled to an optical amplifier/modulator has been realized. Disposed between the optical combiner and the optical amplifier/modulator is an “optical isolator.” The optical isolator includes at least a Faraday rotator and, either solely or in combination with a single polarizer and/or half-wave plate is used to selectively rotate and pass polarized light egressing from the wavelength selectable laser source. Optical isolation is achieved by the egressing radiation from and back reflections incident on the laser source being at two mutually exclusive orthogonal polarization states or by the reflections being totally extinguished. Advantageously, the laser source is unresponsive to orthogonally polarized light, and hence any unwanted back reflections do not substantially affect the operating characteristics of the laser(s).

Abstract: A micro-photoreflectance technique has been developed for performing non-destructive analysis of III-V optoelectronic devices. By using a significantly reduced spot size (for example, 10 micrometers), various compositional features of the device may be analyzed and the Franz-Keldysh oscillations appearing in the micro-photoreflectance wavelength spectra (such as those beyond the barrier/SCL wavelength in an EML structure) may be analyzed to provide information regarding the physical characteristics of the device, such as the electric field and p-i junction placement within an exemplary EML device structure.

Abstract: A method of fabricating an expanded beam optical waveguide device (e.g., a laser), comprises the steps of (a) forming a first semiconductor waveguide region having first and second sections of different thickness and an intermediate vertical taper section of varying thickness coupling the first and second sections to one another, the first waveguide region being effective to expand the size of the beam as it propagates from the first section to the second section, (b) forming a second semiconductor region (e.g., a laser active region) on the first waveguide region, (c) etching the second region so as to form an essentially vertical first surface of length A-B which extends obliquely across the propagation axis of the device, (d) forming a third semiconductor region (e.g.