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CN-121978801-A - Broadband power divider based on bent optical waveguide and design method thereof

CN121978801ACN 121978801 ACN121978801 ACN 121978801ACN-121978801-A

Abstract

The invention relates to the field of integrated optics, in particular to a broadband power divider based on a bent optical waveguide and a design method thereof. The broadband power divider based on the bent optical waveguide consists of a straight-bent waveguide connecting transition section and a bent waveguide coupling section, and the change of an ultra-mode along with the wavelength is counteracted by an asymmetric coefficient introduced by the bent waveguide, so that broadband power division is realized. The design method adopts numerical simulation and two-step fitting, extracts device characteristic parameters, and solves the bending radius and the coupling angle required by broadband operation by combining a coupling mode equation. The invention solves the problems of large insertion loss, high manufacturing requirement and difficult determination of broadband structural parameters in the prior art, can realize the distribution proportion of 50%/50%, 70%/30%, 90%/10%, and the like, has small fluctuation of the distribution proportion in the wide wavelength range of nearly hundred nanometers of the optical communication C/L/O wave band, has low insertion loss, is easy to manufacture, and is suitable for an integrated photon circuit system.

Inventors

  • BI LEI
  • ZHAO XUAN
  • WEI ZIXUAN
  • WU DI
  • QIN JUN
  • DENG LONGJIANG

Assignees

  • 电子科技大学

Dates

Publication Date
20260505
Application Date
20260317

Claims (6)

  1. 1. A broadband power divider based on a curved optical waveguide is characterized by comprising a straight-curved waveguide connecting transition section and a curved waveguide coupling section structure; The straight-bending waveguide connecting transition section is a four-section waveguide with gradually-changed bending radius and is used for enabling the width of the waveguide to be equal to The channel straight waveguide of the (2) is connected to the curved waveguide coupling section according to a curved track with gradually changed curved radius, the distance between the upper waveguide and the lower waveguide is reduced until coupling occurs, and the distance between the waveguides is enlarged after power distribution is completed, so that coupling is completed; The curved waveguide coupling section has a waveguide width of The bending radii are respectively And The bending angles are all The spacing is kept as When the bending radius of the coupling section of the bending waveguide is The bending radius of the inner and outer waveguides is , After entering one curved waveguide at the inner side or the outer side of the coupling section, the light is coupled to the other side, and the light power is distributed into the inner waveguide and the outer waveguide according to the proportion of 50%/50% -90%/10%; bending angle The ratio of the light power distributed to the other side is changed, and the power distribution ratio is also changed along with the wavelength of the input light And adjusting the bending radius and the bending angle, introducing asymmetric coefficients by different inner and outer waveguide radiuses, reducing the power distribution proportion to zero on the derivative of the wavelength, and realizing broadband power distribution.
  2. 2. The broadband power splitter based on curved optical waveguides according to claim 1, wherein the specific power splitting ratio modulation scheme is: According to the optical waveguide coupling mode equation: ; Wherein the method comprises the steps of And Representing the power split ratio of the crossover output and the through output respectively, Is the asymmetry coefficient of the two curved waveguides of the curved waveguide coupling section, ; Is the difference in the supermode propagation constants of the coupled sections of the curved waveguide, Is the extra phase generated by the coupling process; radius of curvature in curved waveguide coupling section And input wavelength When the bending angle is unchanged, the bending angle is different Power distribution ratio of devices under coupling according to Trend of (2) to fit 、 、 Three parameters; In the above 、 、 And wavelength of Relatedly, the cross-terminal power allocation ratio can be obtained by deriving the wavelength: ; For different wavelengths 、 、 Performing linear fitting to obtain 、 、 ; From the above formula, when determining 、 、 、 、 Solving for six parameters Bending angle at the time Here, the The distribution ratio of the power distributor is not changed with the wavelength at the center wavelength and can realize broadband operation in the wavelength range of tens of nanometers, and the bending radius And broadband working bend angle Ratio of distribution And selecting corresponding bending radius and bending angle according to the target distribution ratio required by the broadband power distributor.
  3. 3. The broadband power splitter based on curved optical waveguides of claim 1, wherein said optical waveguide cladding material is silicon dioxide and the core material is silicon nitride or silicon.
  4. 4. The broadband power splitter based on the curved optical waveguide of claim 1, wherein the wavelength band in which the center operating wavelength is located is selected from a C-band 1530nm-1565nm, an L-band 1565nm-1625nm, and an O-band 1260nm-1360nm of optical communications.
  5. 5. The broadband power splitter based on curved optical waveguides of claim 1, wherein the power splitting ratio is 50%/50%,70%/30%,90%/10%.
  6. 6. A method of designing a broadband power splitter based on curved optical waveguides as claimed in any one of claims 1 to 5, comprising the steps of: Step 1, determining a bending waveguide radius corresponding to the radiation loss not exceeding 0.005 dB/DEG according to the width and height of the channel straight waveguide and the working mode Determining the pitch at which channel-to-straight waveguides do not couple ; Step 2, calculating the distance between the coupling sections of the bent waveguide Radius of curvature , Bending angle The curved waveguide coupling section is an arc curve, and the straight-curved waveguide connecting transition section is a curve for connecting the inner side and the outer side of the straight waveguide and the curved waveguide coupling section according to the gradual change of the bending radius; step 3, using electromagnetic simulation software to make the same bending radius different To a broadband power divider of (1) At the central working wavelength In the wavelength range of (1), selecting a plurality of simulation wavelengths at equal intervals, and calculating the power distribution proportion of the device ; The simulation wavelength is fixed so as to As a function of the amount of the independent variable, According to the dependent variable Fitting the trend to obtain 、 、 The wavelength is used as independent variable, and the independent variable is respectively 、 、 Fitting the dependent variable according to a linear relation to obtain the wavelength and the linear relation 、 、 A relationship; Step 4, calculating the wavelength as A kind of electronic device 、 、 、 、 Carrying into the following formula to solve the working angle of the broadband ; ; The angle is calculated using the following Corresponding wideband power allocation ratio ; ; Step 5, changing the bending radius of the bending waveguide coupling section Repeating the steps 2, 3 and 4 to obtain different bending radii Corresponding wideband working angle And power distribution ratio Establishing , , A correspondence relation; Step 6, according to the distribution proportion required by the power distributor in the integrated photon system And Determining wideband operation And 。

Description

Broadband power divider based on bent optical waveguide and design method thereof Technical Field The invention relates to the field of integrated optics, in particular to a broadband power divider based on a bent optical waveguide and a design method thereof, which are suitable for an integrated photon circuit system. Background The optical waveguide power distributor distributes optical signals and optical power according to a certain proportion, is a basic unit device in an integrated photon circuit system, and is widely applied to modulators, frequency modulation continuous wave laser radars and wavelength division multiplexing systems. These applications require that the power divider be nearly constant in the 100nm wide wavelength range around the core wavelength during operation, i.e. have broadband operating characteristics. Meanwhile, because the number of the required power dividers in the integrated photon circuit system is huge, the power dividers have extremely small insertion loss and are easy to manufacture. The traditional optical waveguide power divider realizes power division by directional coupling of light in two straight waveguides with small enough space, and the power division proportion changes to 40% -60% in the wavelength range of 100nm, so that the optical waveguide power divider has no broadband working characteristic. The broadband power divider has been studied at present, wherein the power divider which is coupled through the adiabatic of a wide waveguide and a narrow waveguide needs to occupy a larger area, the insertion loss of a device based on multimode waveguide interference is larger, and the power divider with a sub-wavelength structure has too high requirements on the manufacturing process. Analysis of the theory of coupled modes of optical waveguides shows that the supermode propagation constant of the traditional direct waveguide power divider changes along with the wavelength to cause the power dividing example to be sensitive to the wavelength, the coupled direct waveguide is replaced by a curved waveguide with different inner and outer bending radiuses, and the introduced asymmetric coefficient can counteract the supermode changes along with the wavelength, so that the power dividing example does not change along with the wavelength in a larger range. However, the technology has two problems to be solved, namely, firstly, how to reduce the extra loss caused by introducing bending, and secondly, how to determine the bending radius and the bending angle of the bent waveguide power divider, so that the introduced asymmetry coefficient and the overmode can be accurately counteracted along with the change of the wavelength while the device works in the target power distribution proportion. Disclosure of Invention Aiming at the problems or the defects, the broadband power divider solves the problems that the power divider power dividing ratio is not changed along with the wavelength and the bending radius and the bending angle are difficult to determine because the broadband power divider of the traditional bending optical waveguide adopts bending waveguide coupling to introduce additional loss. The invention provides a width power divider based on a bent optical waveguide and a design method thereof, which reduce the insertion loss of devices and ensure that the designed power divider realizes that the power division ratio hardly changes with wavelength under the target power division ratio. The technical scheme adopted for solving the technical problems is as follows: a broadband power divider based on a curved optical waveguide is composed of a straight-curved waveguide connecting transition section and a curved waveguide coupling section structure. The straight-bending waveguide connecting transition section is a four-section waveguide with gradually-changed bending radius and is used for enabling the width of the waveguide to be equal toThe channel straight waveguide of the (2) is connected to the curved waveguide coupling section according to a curved track with gradually changed curved radius, and meanwhile, the distance between the upper waveguide and the lower waveguide is reduced until coupling occurs, and after power distribution is completed, the distance between the waveguides is enlarged to finish coupling. The curved waveguide coupling section has a waveguide width ofThe bending radii are respectivelyAndThe bending angles are allThe spacing is kept asIs provided. When the bending radius of the bending waveguide coupling section isThe bending radius of the inner and outer waveguides is, . After entering one curved waveguide on the inner side or the outer side of the coupling section, light is coupled to the other side, and the light power is distributed into the inner waveguide and the outer waveguide according to the proportion of 50%/50% -90%/10%. Bending angleThe ratio of the light power distributed to the other side is changed, and the power distributi