A photonic calorimeter converts ionizing radiation dose to heat and includes: a radiation absorber, a temperature compensator disposed within the radiation absorber, a compensation waveguide, a compensation resonator, a compensation resonator, a thermal isolator on which the radiation absorber is disposed and that thermally isolates the radiation absorber from heat loss by thermal transfer due to physical contact by an object, and the temperature compensator changes the optical resonance of the compensation resonator in response to a change in temperature of the radiation absorber due to absorption of the ionizing radiation by the radiation absorber.

A method for fabricating a photonic integrated circuit (PIC) comprises providing a silicon-on-insulator (SOI) wafer comprising an insulator layer disposed between a base semiconductor layer and a SOI layer, wherein the SOI layer comprises a waveguide, providing at least one slot within the SOI layer, wherein the at least one slot is positioned on the same or opposite sides of the waveguide, and wherein the at least one slot is positioned at a predetermined distance away from the waveguide, and removing a portion of the insulator layer to form an etched-out portion of the insulator layer, wherein the etched-out portion is positioned directly beneath the waveguide, and wherein a width of the etched-out portion is at least the width of the waveguide

Back scattering in an optical waveguide at an operating wavelength is controlled by adjusting an optical phase of light propagating in the waveguide at one or more locations along the waveguide. A portion of the back scattered light is tapped off near an input port and coupled into a photodetector. A controller detects changes in the photodetector signal and adjusts an optical phase tuner configured to control the optical phase of light in the waveguide at the selected location or locations. The optical phase tuner may be configured to vary the refractive index of at least a portion of the waveguide.

A method for monitoring optical fiber temperature includes heating an optical fiber using a heat source, and measuring an infrared radiation level emitted by an optical fiber during heating of the optical fiber. The method further includes comparing the infrared radiation level to a radiation level setpoint for the optical fiber to determine a radiation level error value. The method further includes adjusting a power level setpoint of the heat source based on the radiation level error value.

Integrated target waveguide devices and optical analytical systems comprising such devices are provided. The target devices include an optical coupler that is optically coupled to an integrated waveguide and that is configured to receive optical input from an optical source through free space, particularly through a low numerical aperture interface. The devices and systems are useful in the analysis of highly multiplexed optical reactions in large numbers at high densities, including biochemical reactions, such as nucleic acid sequencing reactions. The devices provide for the efficient and reliable coupling of optical excitation energy from an optical source to the optical reactions. Optical signals emitted from the reactions can thus be measured with high sensitivity and discrimination. The devices and systems are well suited for miniaturization and high throughput.

A multipurpose spacer having a spacer body with a ground lead, an inner electrical connection, and an outer electrical connection. The multipurpose spacer provides grounding, securing, and low thermal conductivity advantages. The multipurpose spacer is mounted and connected in an assembly in high-frequency electronics testing devices. The multipurpose spacer provides a substantial reduction in error signal modulation bandwidth and improved high-frequency performance.

Embodiments of the invention describe apparatuses, systems, and methods of thermal management for photonic integrated circuits (PICs). Embodiments include a first device and a second device comprising including waveguides, wherein the first and second devices have different thermal operating conditions. A first region is adjacent to a waveguide of the first device, wherein its optical mode is to be substantially confined by the first region, and wherein the first region has a first thermal conductivity to dissipate heat based on the thermal operating condition of the first device. A second region is adjacent to a waveguide of the second device, wherein its optical mode is to be substantially confined by the second region, and wherein the second region has a second thermal conductivity to dissipate heat based on the thermal operating condition of the second device. In some embodiments, thermal cross talk is reduced without significantly affecting optical performance.

Integrated target waveguide devices and optical analytical systems comprising such devices are provided. The target devices include an optical coupler that is optically coupled to an integrated waveguide and that is configured to receive optical input from an optical source through free space, particularly through a low numerical aperture interface. The devices and systems are useful in the analysis of highly multiplexed optical reactions in large numbers at high densities, including biochemical reactions, such as nucleic acid sequencing reactions. The devices provide for the efficient and reliable coupling of optical excitation energy from an optical source to the optical reactions. Optical signals emitted from the reactions can thus be measured with high sensitivity and discrimination. The devices and systems are well suited for miniaturization and high throughput.

Methods, systems, and devices are disclosed for implementing athermal optical devices based on composite structures having different components with different thermal properties such as a composite structure having materials of positive and negative thermo-optic effects or a composite structure having materials exhibiting different thermal expansion coefficients. In one aspect, a method for providing thermally stabilized optical device structure against temperature fluctuations includes forming an optical device structure to include a first optical material and a second optical material different from the first optical material, in which one of the first and second optical material exhibits a positive thermal-optic effect and the other one exhibits a negative thermal-optic effect, and structuring the first and second optical materials in the optical device structure to reduce a change in an effective refractive index of the optical device structure collectively produced by the first and second optical materials in response to a temperature variation.

Methods, systems, and apparatus, including a photonic integrated circuit package, including a photonic integrated circuit chip, including an active optical element; an electrode configured to receive an electrical signal; a ground electrode; and a bond contact electrically coupled to the electrode; and an ASIC chip including circuitry configured to provide the electrical signal; and a bond contact that is electrically coupled to the circuitry; an bridge chip bonded to at least a portion of the photonic integrated circuit chip and at least a portion of the ASIC chip.