Described embodiments include photonic integrated circuits and systems with photonic devices, including thermal isolation regions for the photonic devices. Methods of fabricating such circuits and systems are also described.

An optical receiver may include a planar lightwave circuit with an optical path and a tapered reflection surface to direct an optical beam toward a top surface of the planar lightwave circuit. The optical receiver may include a photodiode disposed onto the top surface of the planar lightwave circuit such that a receive portion of the photodiode is aligned to the optical path, wherein a gap between the photodiode and the planar lightwave circuit is less than 5 microns.

An optical receiver may include a planar lightwave circuit with an optical path and a tapered reflection surface to direct an optical beam toward a top surface of the planar lightwave circuit. The optical receiver may include a photodiode disposed onto the top surface of the planar lightwave circuit such that a receive portion of the photodiode is aligned to the optical path, wherein a gap between the photodiode and the planar lightwave circuit is less than 5 microns.

An apparatus including a photonic integrated circuit (PIC) coupled to an optical bench is disclosed. The PIC includes at least one grating coupler disposed thereon and the optical bench includes an optical system disposed thereon. The apparatus also includes an integrated heater at an upper surface of the PIC under the optical bench or at a bottom surface of the optical bench over the PIC. The apparatus also includes a layer of solder disposed between the PIC and the optical bench for coupling the bottom surface of the optical bench to the PIC. In some implementations, the layer of solder is in thermal communication with the integrated heater.

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.

Described embodiments include photonic integrated circuits and systems with photonic devices, including thermal isolation regions for the photonic devices. Methods of fabricating such circuits and systems are also described.

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.

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 waveguide structure including a waveguide having a thermally controllable section, and a method of manufacturing the structure. The waveguide structure comprises a plurality of layers. The layers comprise, in order: a substrate (306), a sacrificial layer (305), a lower cladding layer (303), a waveguide core layer (302), and an upper cladding layer (301). The lower cladding layer, waveguide core layer, and upper cladding layer form the waveguide, the waveguide has a waveguide core. The waveguide structure has a continuous via (307) passing through the upper cladding layer, waveguide core layer, and lower cladding layer and running parallel to the waveguide ridge (304) along substantially the whole length of the thermally controllable section. The waveguide structure also has a thermally insulating region (308) in the sacrificial layer extending at least from the via to beyond the waveguide ridge along the whole length of the thermally controllable section. The sacrificial layer comprises a sacrificial material outside of the thermally insulating region, and a thermally insulating gap (308) or thermally insulating material separating the lower cladding layer and substrate inside the thermally insulating region. The structure is manufactured by providing a wet etch to the sacrificial layer through the via in order to remove material from at least the thermally insulating region.

A photonic dosimeter accrues cumulative dose and includes: a substrate; a waveguide disposed on the substrate and that: receives a primary input light; transmits secondary input light from the primary input light to a dosimatrix; receives a secondary output light from the dosimatrix; and produces primary output light from the secondary output light; the dosimatrix disposed on the substrate and in optical communication with the waveguide and that: receives the secondary input light from the waveguide; produces the secondary output light that is communicated to the waveguide; and includes an active element that undergoes conversion from a prime state to a dosed state in response to receipt, by the active element, of a dose of radiation; and a cover layer disposed on waveguide and the dosimatrix.