US-12619027-B2 - Method and apparatus of hybrid integrated photonics devices

Abstract

Embodiments described herein may be related to optical devices and apparatuses directed to forming waveguides and optical phase modulators that enable high baud rate modulation. In one embodiment, an optical phase modulator includes: photonic optical waveguides having their cladding regions and electrical contacts formed by material with its absolute permittivity near zero (ENZ), and their waveguide core region formed by electro-optical (EO) material or silicon PN junction whose optical refractive index changes with strength of externally applied electrical field. The ENZ material described herein further possesses properties of both optical transparency at operating wavelength and electrical conductivity. The ENZ claddings and electrodes may further have dimensions to enable high externally applied electrical field within waveguide core. The EO material described herein includes but not limited to organic polymers, LiNbO 3 , liquid crystals. Other embodiments are described and claimed.

Inventors

• Jin Hong
• Junqiao Wu
• Danqing WANG

Dates

Publication Date

20260505

Application Date

20230218

Claims (3)

1. 1 . A photonic waveguide device comprising: a BOX layer on top of a substrate; a waveguide core region on top of said BOX layer; a waveguide cladding layer on sides of the waveguide core region; a protective layer on top of both the waveguide core region and the waveguide cladding layers; a metal via connecting part of the waveguide cladding layer to a metal pad on the top surface of the device, wherein the waveguide core region is formed by an electro-optic (EO) material having a large electro-optic coefficient or Pockels coefficient which exhibits optical refractive index change when its optic axis is aligned with an externally applied electrical field, and wherein the waveguide core region may comprise both the EO material and a rib formed by either silicon or Si 3 N 4 that connects to a part of the slab waveguide formed by the same material, where the height of the rib is a small fraction of that of the waveguide core region.
2. 2 . The photonic waveguide device of claim 1 , wherein the waveguide core region is formed by a silicon PN junction with a portion of its core width doped with P-type of dopants and the other portion doped with N-type of dopants while the corresponding slab portion of the waveguide core region connecting to the portion of the waveguide core region doped with P-type of dopants and the portion of the waveguide core region doped with N-type of dopants is also doped with the same type of corresponding dopants.
3. 3 . A photonic waveguide device comprising: a BOX layer on top of a substrate; a waveguide core region on top of said BOX layer; a waveguide cladding layer on sides of the waveguide core region; a protective layer on top of both the waveguide core region and the waveguide cladding layers; a metal via connecting part of the waveguide cladding layer to a metal pad on the top surface of the device, wherein the waveguide core region may be left unfilled, which forms a hollow waveguide enclosed by a transparent conducting ENZ cladding layers that confines optical wave tightly inside the waveguide core region for optical refractive index sensing when a certain class of materials is placed inside the waveguide core region for its detection.

Description

CROSS REFERENCE TO RELATED APPLICATION This application claims priority to U.S. Provisional Application No. 63/429,350, filed on Dec. 1, 2022, in the names of Jin Hong, Junqiao Wu and Danqing Wang, entitled “Method and Apparatus of Hybrid Integrated Photonic Devices and Systems,” The disclosure of which is hereby incorporated by reference in its entirety. TECHNICAL FIELD Embodiments of the present disclosure generally relate to the field of semiconductor devices and apparatus, in particular to photonic waveguides and high speed modulators. BACKGROUND Continued growth in computing and mobile devices will continue to increase the demand for high density, large capacity and high speed optical connectivity beyond terabits per second and miniaturized sensing. Current photonic waveguide devices and apparatuses place limits on integration size, density and modulation speed in photonic integrated circuits (PIC). BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates the cross section of a photonic waveguide with ENZ material as cladding layers and electrodes, and EO material as its waveguide core on top of a SiO2 layer, in accordance with various embodiments. FIG. 2 illustrates the cross section of a photonic waveguide with ENZ material as cladding layers and electrodes, and EO material as its waveguide core on top of a thin silicon layer, in accordance with various embodiments. FIG. 3 illustrates the cross section of a photonic waveguide with ENZ material as cladding layers and electrodes, and EO material as its waveguide core and its top insulating layer. FIG. 4 illustrates the cross section of a photonic waveguide with ENZ material as cladding layers and electrodes, and EO material as portion of waveguide core along with a silicon rib in the core. FIG. 5 illustrates the cross section of a photonic waveguide with ENZ material as cladding layers and electrodes wherein portion of the ENZ material extends further onto the box layer, and EO material as portion of waveguide core along with a silicon rib in the core. FIG. 6 illustrates the cross section of a photonic waveguide with ENZ material as cladding layers and electrodes, and a PN-junction based silicon rib as its waveguide core. FIG. 7 illustrates the cross section of two parallel photonic waveguides, sharing the center cladding layer and electrode, with ENZ ITO material as cladding layers and electrodes for both waveguides and EO material as portion of its waveguide core along with a silicon rib in the core of each waveguide. FIG. 8 illustrates the cross section of two parallel photonic waveguides, sharing the center cladding layer and electrode, with ENZ ITO material as cladding layers and electrodes for both waveguides and a PN-junction based silicon rib for each waveguide core. FIG. 9 shows the top view of a block diagram of Mach-Zehnder modulator (MZM), with ENZ material as its waveguide cladding layers and electrodes and EO material or PN junction as its core region. FIG. 10 shows the top view of a micro ring modulator (MRM), with ENZ material as its waveguide cladding layers and electrodes and EO material or PN junction as its core region. FIG. 11 shows the simplified waveguide cross section for simulating optical mode in FIG. 1 and the relative magnitude of transverse electric field (TE mode) and transverse magnetic field (TM mode). FIG. 12 shows the relative magnitude of TE mode and TM mode with different dimensions of waveguide core region. FIG. 13 shows the relative magnitude of TE mode where the waveguide core is enclosed by a two dimensional (2D) rectangular cladding layer made of ENZ material. DETAILED DESCRIPTION Embodiments described herein may be related to designs, devices, apparatuses to enable high speed modulation and high density integration for photonics integrated circuits (PIC) based on silicon photonics platform for beyond 100 GBaud applications. Embodiments described herein may include optical waveguides capable of sharp turns and insensitivity to waveguide wall roughness, photonic waveguides with vacuum core capable of sensing optical index changes, fast tunable waveguide phase shifter enabling beam steering, Mach-Zehnder Modulator (MZM), Micro Ring Modulator (MRM), Multi-Mode Interferometer (MMI), using an ENZ material as both their optical transparent cladding layer and/or their electrical conducting pathway and electrode contacts, and an EO material and/or silicon rib waveguide, or silicon PN junction as their core region of the waveguides. Some of these embodiments facilitate high speeds for a MZM and MRM due to increased optical confinement factor, the enhanced electrical conductivity to contacts close to the core, the reduced device capacitance, the increased electrical field strength across the core region of the waveguides, the extended device length capable of the accumulation of optical phase change, and the reduced sensitivity to manufacturing induced waveguide sidewall roughness that causes losses. Legacy implementations us