US-20260126677-A1 - OPTICAL SOURCES INCLUDING HEATING ELEMENTS AND OPTICAL WAVEGUIDES AND RELATED PHOTONIC INTEGRATED CIRCUIT DEVICES

US20260126677A1US 20260126677 A1US20260126677 A1US 20260126677A1US-20260126677-A1

Abstract

According to some embodiments of the present disclosure, an optical source includes a substrate, a dielectric support layer, an electrically conductive heating element, and an optical waveguide. The dielectric support layer is on a surface of the substrate, and the dielectric support layer includes a dielectric material. The electrically conductive heating element is on the dielectric support layer. The optical waveguide is on the dielectric support layer, and the optical waveguide includes a waveguide material different than the dielectric material of the dielectric support layer. Related photonic integrated circuit (PIC) devices are also disclosed.

Inventors

Marcel W. Pruessner
Steven T. Lipkowitz
Jacob N. Bouchard
Nathan F. Tyndall
Todd H. Stievater

Assignees

THE GOVERNMENT OF THE UNITED STATES OF AMERICA, AS REPRESENTED BY THE SECRETARY OF THE NAVY

Dates

Publication Date: 20260507
Application Date: 20251017

Claims (20)

1 . A optical source comprising: a substrate having a surface; a dielectric support layer on the surface of the substrate, wherein the dielectric support layer comprises a dielectric material; an electrically conductive heating element on the dielectric support layer; and an optical waveguide on the dielectric support layer, wherein the optical waveguide comprises a waveguide material different than the dielectric material of the dielectric support layer.
2 . The optical source according to claim 1 , wherein the substrate defines a trench in the surface thereof, wherein opposite ends of the dielectric support layer are supported on the surface of the substrate on opposite ends of the trench, wherein a central portion of the dielectric support layer is suspended across the trench with the trench defining a void between the central portion of the dielectric support layer and the substrate, and wherein each of the electrically conductive heating element and the optical waveguide is on the central portion of the dielectric support layer.
3 . The optical source according to claim 2 , wherein a length of the heating element is less than a length of the trench.
4 . The optical source according to claim 2 , wherein the void defines an air gap and/or a vacuum between the central portion of the dielectric support layer and the substrate.
5 . The optical source according to claim 1 further comprising: first metal interconnect providing electrical coupling between a first end of the heating element and power supply circuitry; and second metal interconnect providing electrical coupling between a second end of the heating element and the power supply circuitry.
6 . The optical source according to claim 1 , wherein the electrically conductive heating element comprises first and second electrically conductive heating elements on the dielectric support layer, wherein the first and second electrically conductive heating elements are spaced apart.
7 . The optical source according to claim 1 , wherein the dielectric support layer is between the waveguide and the heating element.
8 . The optical source according to claim 1 , wherein the dielectric support layer is a first dielectric support layer, the photonic integrated circuit device further comprising: a second dielectric support layer on the first dielectric support layer and on the optical waveguide so that the optical waveguide is between the first and second dielectric support layers.
9 . The optical source according to claim 1 , wherein a refractive index of the waveguide material is greater than a refractive index of the dielectric material of the dielectric support layer.
10 . The optical source according to claim 1 , wherein the dielectric material of the dielectric support layer is a first dielectric material, wherein the waveguide material comprises a second dielectric material, and wherein the first and second dielectric materials are different.
11 . The optical source according to claim 1 , wherein the electrically conductive heating element is configured to provide optical emission in response to electrical resistive heating, and wherein at least a portion of the optical emission is coupled into the optical waveguide and transmitted through the optical waveguide in a direction parallel the surface of the substrate.
12 . The optical source according to claim 11 , wherein the optical waveguide is optically coupled with a photonic component on the substrate so that the portion of the optical emission is coupled through the optical waveguide to the photonic component on the substrate.
13 . The optical source according to claim 12 , wherein the photonic component comprises at least one of a waveguide, a delay line, an optical cavity filter, a modulator, a chemical/biological sensor, a photodetector, a photodiode, a spectrometer, and/or a spiral waveguide.
14 . The optical source according to claim 12 , wherein the photonic component comprises a spectral filter configured to filter at least a portion of the optical emission coupled through the waveguide.
15 . A photonic integrated circuit (PIC) device, the PIC device comprising: a optical source including, a substrate having a surface, a dielectric support layer on the surface of the substrate, wherein the dielectric support layer comprises a dielectric material, an electrically conductive heating element on the dielectric support layer, and an optical waveguide on the dielectric support layer, wherein the optical waveguide comprises a waveguide material different than the dielectric material of the dielectric support layer; power supply circuitry on the substrate, wherein the power supply circuitry is configured to provide electrical current through the electrically conductive heating element to drive thermal emission of optical output from the electrically conductive heating element due to electrical resistive heating, wherein at least a portion of the optical output is coupled into the waveguide; and a photonic component on the substrate, wherein the optical waveguide is optically coupled with the photonic component so that the portion of the optical emission is coupled through the optical waveguide to the photonic component on the substrate.
16 . The PIC device according to claim 15 , wherein the substrate defines a trench in the surface thereof, wherein opposite ends of the dielectric support layer are supported on the surface of the substrate on opposite ends of the trench, wherein a central portion of the dielectric support layer is suspended across the trench with the trench defining a void between the central portion of the dielectric support layer and the substrate, and wherein each of the electrically conductive heating element and the optical waveguide is on the central portion of the dielectric support layer.
17 . An optical source comprising: a substrate having a surface, wherein the substrate defines a trench in the surface thereof; a dielectric support layer on the surface of the substrate, wherein the dielectric support layer comprises a dielectric material, wherein opposite ends of the dielectric support layer are supported on the surface of the substrate on opposite ends of the trench, wherein a central portion of the dielectric support layer is suspended across the trench with the trench defining a void between the central portion of the dielectric support layer and the substrate; an optical emission element on the central portion of the dielectric support layer, wherein the void is between the optical emission element and the substrate; and an optical waveguide on the central portion of the dielectric support layer, wherein the void is between the optical waveguide and the substrate, and wherein the optical waveguide comprises a waveguide material different than the dielectric material of the dielectric support layer.
18 . The optical source according to claim 17 , wherein the optical emission element comprises an electrically conductive heating element.
19 . A photonic integrated circuit (PIC) device, the PIC device comprising: a optical source including, a substrate having a surface, wherein the substrate defines a trench in the surface thereof, a dielectric support layer on the surface of the substrate, wherein the dielectric support layer comprises a dielectric material, wherein opposite ends of the dielectric support layer are supported on the surface of the substrate on opposite ends of the trench, wherein a central portion of the dielectric support layer is suspended across the trench ( 703 ) with the trench ( 703 ) defining a void between the central portion of the dielectric support layer ( 711 b ) and the substrate ( 701 ), an optical emission element on the central portion of the dielectric support layer, wherein the void is between the optical emission element and the substrate, and an optical waveguide on the central portion of the dielectric support layer, wherein the void is between the optical waveguide and the substrate, and wherein the optical waveguide comprises a waveguide material different than the dielectric material of the dielectric support layer; power source circuitry on the substrate, wherein the power source circuitry is configured to provide electrical current through optical emission element to drive optical output from the optical emission element, wherein at least a portion of the optical output is coupled into the waveguide; and a photonic component on the substrate, wherein the optical waveguide is optically coupled with the photonic component so that the portion of the optical output is coupled through the optical waveguide to the photonic component on the substrate.
20 . The PIC device according to claim 19 , wherein the optical emission element comprises an electrically conductive heating element.

Description

CROSS-REFERENCE This Application is a Nonprovisional Utility Patent Application and claims the benefit of priority under 35 U.S.C. Sec. 119 based on U.S. Provisional Patent Application No. 63/715,678 filed on Nov. 4, 2024. The disclosures of Provisional Application No. 63/715,678 and all references cited herein are hereby incorporated in their entirety by reference into the present disclosure. FEDERALLY-SPONSORED RESEARCH AND DEVELOPMENT The United States Government has ownership rights in this invention. Licensing inquiries may be directed to Office of Technology Transfer, US Naval Research Laboratory, Code 1004, Washington, D.C. 20375, USA; +1.202.767.7230; nrltechtran@us.navy.mil, referencing Navy Case #212402. TECHNICAL FIELD The present disclosure relates generally to optics, and more particularly to optical sources and related photonic integrated circuit devices. BACKGROUND Photonic integrated circuits (PICs) may provide large-scale combination of many photonic components on a chip-scale platform. This integration is enabled by silicon photonic foundries with wafer-scale (up to 300 mm diameter, see Reference [1]) fabrication capabilities using state-of-the-art CMOS tools. While the majority of photonic components, e.g. waveguides, delay lines, optical cavity filters, and modulators, are now available from foundries (see References [2] and [3]) via process design kits (PDKs) (see References [1], [2], and [4]), on-chip integrated optical sources are still lacking. A variety of methods to integrate silicon and silicon nitride (SiN) PICs with direct bandgap materials suitable for lasing or amplification have been proposed (see References [5] and [7]). However, all of these methods may generally require substantial, experimental modifications to existing foundry processes, often increasing cost and/or decreasing yield. In addition, on-chip laser-based sources tend to focus on specific narrow optical bands, and may be unsuitable for broadband applications such as sensing or component verification. Chemical sensors enabled by optical waveguide absorption spectroscopy (see References [8] and [9]) rely on changes in the loss spectrum in the presence of chemical analytes over a broad wavelength range without requiring a narrow linewidth optical source. While on-chip detection of small-molecule gases has been demonstrated using off-chip lasers (see Reference [10]), inexpensive and monolithically integrated broadband optical sources in the near-infrared may be useful to enable true sensor systems-on-a chip. Additionally, a variety of gases including NH3, CO2, CO and NO exhibit rich absorption spectra in the 1-10 μm range (see Reference [11]) making thermal sources ideal for absorption spectroscopy. Although chip-scale surface-normal thermal emitters have previously been demonstrated (see References [12]-[17]), few emitters have been coupled to on-chip waveguides (see References [18]-[21]). A foundry-integrated broadband near-infrared optical source based on hot carriers in a silicon (Si) p-i-n waveguide was demonstrated in Reference at wavelengths λ≈> 1100 nm (limited by band edge absorption in the Si waveguide). SUMMARY This summary is intended to introduce, in simplified form, a selection of concepts that are further described in the Detailed Description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. Instead, it is merely presented as a brief overview of the subject matter described and claimed herein. According to some embodiments of inventive concepts, an optical source includes a substrate, a dielectric support layer, an electrically conductive heating element, and an optical waveguide. The dielectric support layer is on a surface of the substrate, and the dielectric support layer comprises a dielectric material. The electrically conductive heating element is on the dielectric support layer. The optical waveguide is on the dielectric support layer, and the optical waveguide comprises a waveguide material different than the dielectric material of the dielectric support layer. According to some other embodiments of inventive concepts, a photonic integrated circuit (PIC) device includes an optical source, power supply circuitry, and a photonic component. The optical source includes a substrate, a dielectric support layer, an electrically conductive heating element, and an optical waveguide. The dielectric support layer is on the surface of the substrate, and the dielectric support layer comprises a dielectric material. The electrically conductive heating element is on the dielectric support layer. The optical waveguide is on the dielectric support layer, and the optical waveguide comprises a waveguide material different than the dielectric material of the dielectric support layer. The power supply circuitry is on the substrate, and the power supply circuitry is conf