WO2024010518A1 - Terminateur de guide d'ondes - Google Patents

Terminateur de guide d'ondes Download PDF

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Publication number
WO2024010518A1
WO2024010518A1 PCT/SG2022/050474 SG2022050474W WO2024010518A1 WO 2024010518 A1 WO2024010518 A1 WO 2024010518A1 SG 2022050474 W SG2022050474 W SG 2022050474W WO 2024010518 A1 WO2024010518 A1 WO 2024010518A1
Authority
WO
WIPO (PCT)
Prior art keywords
waveguide
terminator
section
shaped
tapered
Prior art date
Application number
PCT/SG2022/050474
Other languages
English (en)
Inventor
Chee Wei LEE
Original Assignee
Compoundtek Pte. Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Compoundtek Pte. Ltd. filed Critical Compoundtek Pte. Ltd.
Priority to PCT/SG2022/050474 priority Critical patent/WO2024010518A1/fr
Publication of WO2024010518A1 publication Critical patent/WO2024010518A1/fr

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Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/241—Light guide terminations
    • G02B6/243—Light guide terminations as light absorbers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/1228—Tapered waveguides, e.g. integrated spot-size transformers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B2006/12083—Constructional arrangements
    • G02B2006/12126—Light absorber

Definitions

  • the disclosures made herein relate generally to silicon photonics, and more particularly to a waveguide terminator for coupling with a waveguide port of a photonic device i.e. silicon nitride (SiN) photonic circuit.
  • a photonic device i.e. silicon nitride (SiN) photonic circuit.
  • PIC photonic integrated circuits
  • Si silicon
  • SiN silicon nitride
  • a waveguide terminator is a prevalent and unavoidable device, where some output ports of a device are not used and not connected to any part of the PIC.
  • a waveguide terminator if not designed properly, generates substantial back-reflection to the PIC, as shown in FIGURE 1. This not only interferes with existing optical signals in the circuit, but also affects laser sources and photodetectors and deteriorates their performance. As such, it is imperative to have an effective waveguide terminator, which can reduce the back- reflection optical intensity to a minimal level that is acceptable level by the circuit.
  • Back reflection or Optical return Loss (ORL) is calculated as follows:
  • ORL lOlog (Pe/Pr), where Pe is emitted power and Pr reflected power, expressed in Watt (W). Typically, ORL for a terminator device is expected to >40dB.
  • one technique uses relatively long waveguides to terminate the unused ports. As light propagates along the long waveguides, it gradually diminishes due to the propagation loss of the waveguides which is predominately optical scattering loss and converts the optical signal mostly to stray light.
  • it may require impractically long waveguide to achieve a reasonable attenuation.
  • Another technique uses a waveguide inverse taper with reducing waveguide width.
  • the optical mode gradually loses confinement and light is diffracted into claddings surrounding the waveguide and becoming stray light.
  • sufficient length for the devices is required for high performance terminators with high light attenuation and low reflection.
  • such long devices might take up a large chip area and become an issue in many circuits having a high level of integration.
  • United States Patent No.: US 10,527,792 B2 discloses an optical waveguide termination comprising a light-receiving inlet for receiving light to be terminated and a curved section defining a spiral waveguide, for example a logarithmic spiral, having a waveguide width that continuously decreases from the inlet to the tip proposed to use a spiral optical waveguide design to reduce the footprint of the terminator.
  • United States Patent Publication No.: US 2015/0212271 Al proposed an optical waveguide terminator with a doped waveguide. By inducing impurities (dopants) into the silicon waveguide with enhanced light absorption, a terminator with reduced length (size) can be realized. However, there is room for further improvement in realizing effective termination to minimize back reflection without complicating the structure of the terminator and without increasing size of the terminator.
  • the present invention relates to a waveguide terminator to be coupled with a waveguide port of a photonic chip.
  • the terminator comprises an input waveguide section with a first end and a second end opposite to the first end.
  • the first end is capable being optically coupled with the waveguide port for receiving a light wave from the waveguide port and the second end formed as an adiabatic down-tapered waveguide section.
  • a light dissipation section is provided for dissipating a light wave exiting the second end of the input waveguide section.
  • a cladding encloses the input waveguide section and the light dissipation section.
  • the light dissipation section includes a plurality of shaped waveguides arranged in an array.
  • Each shaped waveguide is formed of at least two adiabatic down-tapered waveguide sections, wherein each adiabatic down-tapered waveguide section includes two angled facets and a perpendicular facet. Length of each perpendicular facet is less than 0.15nm.
  • Each shaped waveguide is positioned with respect to a longitudinal axis of the input waveguide section, such that each angled facet of the shaped waveguide forms an acute angle with respect to the longitudinal axis of the input waveguide section.
  • refractive index of each shaped waveguide is greater than refractive of the cladding.
  • One of the adiabatic down-tapered waveguide sections faces towards the input waveguide section and the other of the adiabatic down-tapered waveguide sections faces away from the input waveguide section.
  • the cladding is a silicon dioxide (SiO2) cladding.
  • SiO2 silicon dioxide
  • Each shaped waveguide is spaced apart from the adjacent shaped waveguides by a gap width within a range of 0.1 -0.5 micrometers (pm). Length of each of the adiabatic down-tapered waveguide sections is at least 2 pm.
  • the gap width between adjacent shaped waveguides is 0.3 pm. Furthermore, the length of each of the adiabatic down-tapered waveguide sections is 3 pm.
  • FIGURE 1 shows a schematic representation of back-reflection phenomena in a typical waveguide terminator, in accordance with prior art.
  • FIGURE 2 shows a longitudinal section view of the waveguide terminator, in accordance one embodiment of the present invention.
  • FIGURE 3 shows graphical representation of simulated test results of the terminator.
  • the present invention relates to a waveguide terminator that can coupled to a waveguide port of a photonic chip.
  • the terminator includes an input waveguide section and a set of shaped waveguides arranged in an array including multiple stages positioned with respect to a longitudinal axis of the input waveguide section, wherein each facet of each shaped waveguide is at an acute angle with respect to the longitudinal axis. Since the facets make an acute angle with the longitudinal axis back-reflection is minimized very effectively while keeping the terminator compact.
  • FIGURE 2 shows a longitudinal section view of a waveguide terminator (1), in accordance one embodiment of the present invention.
  • the terminator (1) comprises an input waveguide section (10, a light dissipation section (20) and a cladding (30) enclosing the input waveguide section (10) and the light dissipation section (20).
  • the input waveguide section (10) includes a first end (11) capable being optically coupled with a waveguide port for receiving a light wave from the waveguide port and a second end (12) opposite to the first end (11) formed as an adiabatic down-tapered waveguide section.
  • the light dissipation section (20) is capable of dissipating a light wave exiting the second end (12) of the input waveguide section (10).
  • a plurality of shaped waveguides (21) is arranged in an array of one or more stages, wherein each shaped waveguide (21) is positioned with respect to a longitudinal axis of the input waveguide section (10).
  • Each shaped waveguide (21) includes at least two adiabatic down-tapered waveguide sections (21a, 21b), wherein one of the adiabatic down-tapered waveguide sections (21a, 21b) faces towards the input waveguide section (10) and the other of said adiabatic down-tapered waveguide sections (21a, 21b) faces away from the input waveguide section (10).
  • Each of the adiabatic down-tapered waveguide sections (21a, 21b) is formed with two angled facets (22) and one perpendicular facet (23).
  • Each angled facet (22) of the shaped waveguide (21) forms an acute angle (a) with respect to the longitudinal axis of the input waveguide section, while each perpendicular face (23) is at right angle with respect to the longitudinal axis.
  • the angle ( ⁇ z) between each angled facet (22) with respect to the longitudinal axis is within a range of 1-89 degrees and length of each perpendicular facet (23) is less than 0.15nm.
  • the angle (a) is within a range of 10-30 degrees and the length of each perpendicular facet (23) is less than O.lnm.
  • Refractive index of each shaped waveguide (21) is greater than refractive of the cladding (30).
  • the cladding (30) is a silicon dioxide (SiC ) cladding and the waveguide port is a part of a photonic device such as silicon nitride (SiN) circuit or chip.
  • width of the first end (11) of the input waveguide section (10) is 1 pm and thickness of the first end (11) is 0.4 pm.
  • Each shaped waveguide (21) is spaced apart from the adjacent shaped waveguides (21) by a gap width within a range of 0.1 -0.5 micrometers (pm).
  • Length (L) of each of the adiabatic down-tapered waveguide sections (21a, 21b) is at least 2 pm. More preferably, the gap width is 0.3 pm and L is 3 pm.
  • the terminator (1) is capable of effectively reducing back-reflection intensity level, while allowing mass fabrication together with same process of fabricating other SiN photonic devices on chip without incurring additional step or cost.
  • the reflection level can be varied by adjusting a number of stages in the array as illustrated in FIGURE 3 which shows a graphical representation simulation test results of the present invention.
  • the number of stages of the shaped waveguides is set as 2 and L is fixed as 3pm. It can be clearly seen from the test results for a fixed L and gap width between the shaped waveguides, the back reflection is reduced as the number of stages of the shaped waveguide is increased.
  • a light wave inputted to the input waveguide section (10) is gradually dissipated through the down-taper waveguide section to the light dissipation section (20).
  • the shaped waveguides (21) are made of a material with higher refractive index as compared to that of the cladding (30), so to attract the light wave towards the shaped waveguides (21). Due to the configuration of the facets (22, 23) of the adiabatic down-tapered waveguide sections (21a, 21b) and multiple stages of the shaped waveguides (21), the light wave is heavily dissipated down the stages. Therefore, back reflection of the light wave is effectively minimized without complicating a structure or manufacturing of the terminator (1).
  • the shaped waveguides not only maintains the incident angle of the light wave on the angled facets (22) to be less than 90 degrees but also to ensures compactness of the terminator (1).

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Optical Integrated Circuits (AREA)

Abstract

La présente invention concerne un terminateur de guide d'ondes (1), comprenant une section de guide d'ondes d'entrée (10), une section de dissipation de lumière (20) et une gaine (30). La section de guide d'ondes d'entrée (10) comprend une première extrémité (11) pouvant être couplée optiquement à un port de guide d'ondes pour recevoir une onde lumineuse provenant du port de guide d'ondes et une seconde extrémité (12) opposée à la première extrémité (11) formée sous la forme d'une section de guide d'ondes effilée vers le bas adiabatique. La section de dissipation de lumière (20) est capable de dissiper une onde lumineuse sortant de la seconde extrémité (12) de la section de guide d'ondes d'entrée (10). La gaine (30) renfermant la section de guide d'ondes d'entrée (10) et la section de dissipation de lumière (20).
PCT/SG2022/050474 2022-07-08 2022-07-08 Terminateur de guide d'ondes WO2024010518A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/SG2022/050474 WO2024010518A1 (fr) 2022-07-08 2022-07-08 Terminateur de guide d'ondes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/SG2022/050474 WO2024010518A1 (fr) 2022-07-08 2022-07-08 Terminateur de guide d'ondes

Publications (1)

Publication Number Publication Date
WO2024010518A1 true WO2024010518A1 (fr) 2024-01-11

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Family Applications (1)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090067797A1 (en) * 2007-09-06 2009-03-12 Kla-Tencor Technologies Corporation Optical waveguide radiation control
KR101054357B1 (ko) * 2010-04-13 2011-08-04 한국과학기술원 마이크로 채널 내의 3차원 액체 코어 및 액체 클래딩을 이용한 옵티컬 웨이브 가이드 장치 및 그 장치를 이용한 옵티컬 웨이브 가이드 방법
US20110310913A1 (en) * 2007-09-24 2011-12-22 Nufern Optical fiber laser, and components for an optical fiber laser, having reduced susceptibility to catastrophic failure under high power operation
US20150219851A1 (en) * 2014-01-31 2015-08-06 Ofs Fitel, Llc Termination Of Optical Fiber With Low Backreflection
US20190292590A1 (en) * 2008-09-16 2019-09-26 Pacific Biosciences Of California, Inc. Substrates and optical systems and methods of use thereof

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090067797A1 (en) * 2007-09-06 2009-03-12 Kla-Tencor Technologies Corporation Optical waveguide radiation control
US20110310913A1 (en) * 2007-09-24 2011-12-22 Nufern Optical fiber laser, and components for an optical fiber laser, having reduced susceptibility to catastrophic failure under high power operation
US20190292590A1 (en) * 2008-09-16 2019-09-26 Pacific Biosciences Of California, Inc. Substrates and optical systems and methods of use thereof
KR101054357B1 (ko) * 2010-04-13 2011-08-04 한국과학기술원 마이크로 채널 내의 3차원 액체 코어 및 액체 클래딩을 이용한 옵티컬 웨이브 가이드 장치 및 그 장치를 이용한 옵티컬 웨이브 가이드 방법
US20150219851A1 (en) * 2014-01-31 2015-08-06 Ofs Fitel, Llc Termination Of Optical Fiber With Low Backreflection

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