Programmable discrete fractional Fourier transform optical implementation device

Abstract

The invention provides an optical implementation device for programmable discrete fractional Fourier transform. The optical implementation device comprises an optical interconnection network and a basic transformation unit, the optical implementation device is formed by cascading an optical interconnection network and a plurality of basic conversion units; the optical interconnection network comprises: a Mach-Zehnder interferometer; the basic transformation unit is a basic transformation unit for realizing fractional Fourier orders with the same or different orders; the basic transformation unit is obtained through an inverse design method; the dynamic regulation and control of the optical implementation device from any order between 0 and 2pi is realized by regulating and controlling the communication state of the Mach-Zehnder interferometer; the basic transformation unit obtained based on the inverse design method occupies a small physical area on a silicon-based platform, and the optical interconnection network is realized by a Mach-Zehnder interferometer and has the advantage of being integratable. By regulating and controlling the communication state of the Mach-Zehnder interferometer, the order is dynamically adjusted, and programming of the fractional order Fourier transform optical implementation device is achieved.

Description

Technical Field

[0001] This invention relates to the field of optical realization devices, and more particularly to an optical realization device for programmable discrete fractional Fourier transform. Background Technology

[0002] Currently, there are three main approaches to optically implementing the fractional Fourier transform (FrFT). The first approach uses free-space lens systems (such as the 4f optical architecture) from space optics, achieving theoretically high-precision transformations through cascaded lens groups. However, this relies on meter-scale optical paths (typically >1 meter), resulting in a large system size that is difficult to miniaturize. More importantly, such systems typically use fixed optical components, making it impossible to dynamically adjust the order parameters of the fractional transform, severely limiting their applicability in real-time signal processing scenarios. For example, while the prism-lens combination architecture proposed by Lohmann et al. can achieve basic FrFT operations, order switching requires manual replacement of optical components, which cannot meet the dynamic tuning requirements of applications such as radar imaging.

[0003] The second approach is a fiber-based time-domain lensing system that utilizes nonlinear self-phase modulation to achieve order tuning. A typical implementation uses pump pulses to induce the Kerr effect in kilometer-long fibers, generating an equivalent "time lens." Although this approach supports electrically controlled order adjustment, its reliance on ultra-long transmission distances leads to a significant increase in system size and power consumption, and fiber dispersion introduces additional phase errors. Research by Cuadrado-Laborde et al. has demonstrated that monochromatic dispersion devices can reduce the distance to some extent, but still require hundreds of meters of fiber, making integration into chip platforms difficult.

[0004] The third approach is the integrated evanescent coupled waveguide array proposed by Weimann et al. By controlling the weak coupling effect between waveguides, the order of the FrFT can be obtained by varying the propagation positions of the waveguides. While this approach has the potential for chip integration, it inherently lacks order reconfigurability due to the fixed coupling coefficients between waveguides and the strong correlation between transmission distance and transform order. More seriously, specific orders require customized waveguide arrays of specific lengths (e.g., π / 2 order requires a specific length), resulting in low hardware resource reuse and an inability to support dynamic switching requirements across multiple orders.

[0005] All three approaches suffer from fundamental contradictions: the free-space and fiber optic approaches are constrained by macroscopic physical effects, contradicting the miniaturization trend of photonic integrated circuits. While the integrated waveguide approach achieves micro- and nano-scale fabrication, it comes at the cost of reconfigurability. This situation, where "reconfigurability and integration are mutually exclusive," has become a core bottleneck hindering the application of FrFT technology in scenarios such as real-time synthetic aperture radar imaging and dynamic optical encryption. Summary of the Invention

[0006] This invention provides a programmable optical implementation device for discrete fractional Fourier transform, which solves the problem of the incompatibility between reconfigurability and integration in the prior art, and achieves programmability and integrability.

[0007] This invention provides a programmable optical implementation device for discrete fractional Fourier transform, comprising: Optical interconnect networks and basic conversion units; The optical realization device consists of an optical interconnect network and multiple cascaded basic transformation units; Optical interconnect network, including: Mach-Zehnder interferometer; basic transformation unit is a basic transformation unit that realizes the same or different fractional Fourier orders; The basic transformation unit is obtained through inverse design; the dynamic control of the optical realization device from any order between 0 and 2π is achieved by controlling the connectivity state of the Mach-Zehnder interferometer array.

[0008] According to the present invention, an optical implementation device for a programmable discrete fractional Fourier transform is provided. The basic transform unit is obtained through an inverse design method and includes: The basic transformation unit is generated by using a dielectric constant parameterized model, based on frequency domain electromagnetic simulation and regular constraints.

[0009] According to the present invention, an optical implementation device for a programmable discrete fractional Fourier transform is provided. The dynamic control of the optical implementation device from any order between 0 and 2π is achieved by controlling the connectivity state of a Mach-Zehnder interferometer array, including: Based on the target order of the optical realization device, the combination relationship of multiple basic transformation units is determined; wherein, the combination relationship is realized based on the principle of order additivity; The connectivity state of the Mach-Zehnder interferometer array is controlled based on the combination relationship.

[0010] According to the present invention, an optical implementation device for a programmable discrete fractional Fourier transform is provided, wherein the combination relationship includes the configuration state of multiple basic transform units: the configuration state is required or not required; and the connectivity state of the Mach-Zehnder interferometer array is adjusted according to the combination relationship, including: When the configuration state of the basic transformation unit is required, the connectivity state of the previous Mach-Zehnder interferometer array set in the basic transformation unit will be adjusted to a through state or a cross state to pass through the basic transformation unit. When the configuration state of the basic transformation unit is not needed, the connectivity state of the previous Mach-Zehnder interferometer array set in the basic transformation unit will be adjusted to a through state or a cross state to bypass the basic transformation unit.

[0011] According to the present invention, an optical implementation device for a programmable discrete fractional Fourier transform, an optical interconnection network, further includes: a first phase shifter and a second phase shifter; The array configuration of multiple Mach-Zehnder interferometers is set up by a first phase shifter, a second phase shifter, and two multimode interferometers.

[0012] According to the present invention, an optical implementation device for a programmable discrete fractional Fourier transform is provided. The optical implementation device is composed of an optical interconnection network and a cascaded basic transform unit, including: The optical realization device consists of an array of multiple Mach-Zehnder interferometers and multiple basic transformation units of the same or different orders; After the input signal enters from the optical realization device, the passage state of the input signal is determined by the array routing of multiple sets of Mach-Zehnder interferometers; the order of the output signal is determined by multiple basic transformation units of the same or different orders and order mapping rules.

[0013] According to the present invention, an optical implementation device for a programmable discrete fractional Fourier transform is provided. The order mapping rule is based on binary decomposition and is implemented by the following formula: in, For the target order, For binary selection coefficients; M is the cascade series. This is the nth basic transformation unit; The order corresponding to the basic transformation unit, including .

[0014] The present invention provides a programmable optical implementation device for discrete fractional Fourier transform, comprising: an optical interconnect network and a basic transformation unit; the optical implementation device is composed of a cascaded optical interconnect network and a basic transformation unit; the optical interconnect network includes a Mach-Zehnder interferometer; the basic transformation unit is a basic transformation unit for realizing the same or different fractional Fourier orders; the basic transformation unit is obtained through an inverse design method; the dynamic control of any order of the optical implementation device from 0 to 2π is achieved by controlling the connectivity state of the Mach-Zehnder interferometer array; the basic transformation unit obtained based on the inverse design method occupies a small physical area on a silicon-based platform, and the optical interconnect network is implemented by a basic Mach-Zehnder interferometer, which has the advantage of integrability, supports standard silicon photonics fabrication processes, and the overall size of the optical implementation device is reduced by three orders of magnitude compared to traditional free-space systems. By controlling the connectivity state of the Mach-Zehnder interferometer array, the dynamic control of any order of the optical implementation device from 0 to 2π is achieved, thus realizing the programmability of the optical implementation device. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of the programmable discrete fractional Fourier transform optical implementation device provided by the present invention.

[0017] Figure 2 This invention provides a programmable optical implementation device for discrete fractional Fourier transform.

[0018] Figure 3 This is a micro / nano structure diagram of the basic transformation unit provided by the present invention, and the fidelity and insertion loss curves of the cascaded optical realization device. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0020] The following is combined with Figures 1-3 This invention is described.

[0021] Figure 1 This is a schematic diagram of the programmable discrete fractional Fourier transform optical implementation device provided by the present invention, as shown below. Figure 1 As shown, the optical realization device includes: Optical interconnect network 101 and multiple basic transformation units 102; The optical realization device is composed of an optical interconnection network 101 and a basic transformation unit 102 cascaded together; Optical interconnection network 101 includes: a Mach-Zehnder interferometer; and a basic transformation unit 102, which is used to implement basic transformation units 102 with the same or different fractional Fourier orders. The basic transformation unit 102 is obtained through inverse design; the dynamic control of the optical realization device from any order between 0 and 2π is achieved by controlling the connectivity state of the Mach-Zehnder interferometer array.

[0022] Specifically, this invention proposes a programmable DFrFT optical implementation device, characterized by its programmability and integrability. This optical implementation device consists of a cascaded optical interconnect network constructed from a Mach-Zehnder interferometer (MZI) array and basic transformation units of a specific order implemented using inverse design methods. Utilizing the additivity of the FrFT order, this system can dynamically control and programmably implement any FrFT order from 0 to 2π by adjusting the connectivity state (through state or cross state) of the MZI array.

[0023] The optical interconnect network 101 includes a Mach-Zehnder interferometer or optical control elements such as microrings.

[0024] The implementation methods of the basic transformation unit include inverse design / waveguide array or MZI mesh structure.

[0025] This invention enables real-time programming of fractional orders based on an MZI interconnect network architecture. In the optical implementation device, a phase shifter regulates the connectivity, pass-through, or crossover state of the MZI, thereby controlling the final output order of the optical implementation device. Therefore, by adjusting the applied voltage on the phase shifter, real-time programming of the order can be achieved. To our knowledge, this is the first solution to simultaneously possess both integrability and programmability.

[0026] Among them, the control methods on MZI include thermal tuning, electrical tuning, and non-destructive phase change materials.

[0027] Optionally, in the optical implementation device for a programmable discrete fractional Fourier transform provided by the present invention, the basic transform unit 102 is obtained through an inverse design method and includes: Based on the dielectric constant parameterization model, and according to frequency domain electromagnetic simulation and regular constraints, the basic transformation unit 102 is generated.

[0028] Specifically, this invention achieves miniaturization of the basic transformation unit through inverse design. For the four core DFrFT orders (e.g., π / 8, π / 4, π / 2, π), a dielectric constant parameterization model (for silicon material) is employed. p =1, silicon dioxide p =0), combining electromagnetic simulation and canonical constraints, a subwavelength topological micro / nano structure is generated. The optimized four sets of basic transformation units occupy only a 3.6μm × 3.6μm physical area on the silicon-based platform. The optical interconnect network is realized by combining basic multimode interferometer and phase shifter structures, which also has the advantage of integrability, supports standard silicon photonics process fabrication, and the overall optical realization device size is reduced by three orders of magnitude compared with traditional free-space systems. This all-chip integrated solution fundamentally overcomes the physical limitations of the kilometer-level transmission distance required by fiber optic systems and the meter-level volume of free-space lenses.

[0029] Optionally, according to the programmable optical implementation device for discrete fractional Fourier transform provided by the present invention, the dynamic control of the optical implementation device from any order between 0 and 2π is achieved by controlling the connectivity state of the Mach-Zehnder interferometer array, including: Based on the target order of the optical realization device, the combination relationship of multiple basic transformation units is determined; wherein, the combination relationship is realized based on the principle of order additivity; The connectivity state of the Mach-Zehnder interferometer array is controlled based on the combination relationship.

[0030] According to the present invention, an optical implementation device for a programmable discrete fractional Fourier transform is provided, wherein the combination relationship includes the configuration state of multiple basic transform units: the configuration state is required or not required; and the connectivity state of the Mach-Zehnder interferometer array is adjusted according to the combination relationship, including: When the configuration state of the basic transformation unit is required, the connectivity state of the previous Mach-Zehnder interferometer array set in the basic transformation unit will be adjusted to a through state or a cross state to pass through the basic transformation unit. When the configuration state of the basic transformation unit is not needed, the connectivity state of the previous Mach-Zehnder interferometer array set in the basic transformation unit will be adjusted to a through state or a cross state to bypass the basic transformation unit.

[0031] Specifically, because FrFT has the property of order additivity, that is: Therefore, a higher-order FrFT operator can be derived from multiple lower-order operators. This is achieved through cascading. Utilizing this property, the present invention proposes a structure for a programmable DFrFT optical realization device. Figure 2 This is a programmable optical implementation device for discrete fractional Fourier transform. For example... Figure 2 As shown, the optical realization device consists of four basic transformation units ( It consists of an interconnected network of multiple MZI arrays, supporting the processing of complex signals in four dimensions (N=4).

[0032] The combination relationship of multiple basic transformation units is realized based on the principle of order additivity; the combination and selection relationship of multiple basic units determines the range and resolution of the target order; the present invention will select appropriate order mapping rules according to actual needs to achieve the target order.

[0033] Optionally, according to the optical implementation device for a programmable discrete fractional Fourier transform provided by the present invention, the optical interconnection network 101 further includes: a first phase shifter and a second phase shifter; The array configuration of multiple Mach-Zehnder interferometers is set up by a first phase shifter, a second phase shifter, and two multimode interferometers.

[0034] Optionally, according to the present invention, an optical implementation device for a programmable discrete fractional Fourier transform is provided. The optical implementation device is composed of a cascaded optical interconnection network 101 and a basic transform unit 102, comprising: The optical realization device consists of an array of multiple Mach-Zehnder interferometers and multiple basic transformation units 102 of the same or different orders; After the input signal enters from the optical realization device, the passage state of the input signal is determined by the array routing of multiple sets of Mach-Zehnder interferometers; the order of the output signal is determined by four basic transformation units 102 of different orders and the order mapping rule.

[0035] Specifically, the input signal first enters the optical realization device, passes through the MZI array, and includes a phase shifter. and Together, they determine the configuration of the MZI array. This reconfigurable network controls the signal path by setting each MZI array to a cross state (e.g., stage 1, orange) or a bar state (e.g., stage 2, green), thereby determining whether the signal should pass through the current basic transformation unit or bypass it entirely. After passing through the selected propagation path, the transformed signal is routed to the output port for detection.

[0036] Optionally, in the optical implementation device for the programmable discrete fractional Fourier transform provided by the present invention, the order mapping rule is implemented by the following formula: in, For the target order, For binary selection coefficients; M is the cascade series. For which basic transformation unit 102; The order corresponding to the basic transformation unit, including .

[0037] Specifically, the order mapping rules are configurable and not limited to binary decomposition. By adjusting the set of orders of the basic transformation units and the corresponding selection rules, different order resolution requirements can be accommodated. For example, equally spaced order combinations (such as { π / 4, π / 4, π / 4, π / 4}) or other irregular order combinations (such as { π / 6, π / 3, π / 2, π}) serves as the basis for mapping, thus connecting 0 to 2 π This invention enables more refined or application-specific order coverage within a given range. This design significantly enhances the flexibility and applicability of the optical implementation device, while ensuring order integrity (covering the entire range from 0 to 2π) and improving the efficiency of order transformation (reducing the number of cascaded stages). The invention utilizes the principle of order additivity of fractional Fourier transform operators to achieve arbitrary target orders. It can be represented as a combination of several base orders, i.e.: in, is a binary selection coefficient, indicating whether to introduce the corresponding basic transformation unit; M is the cascade number; For which basic transformation unit 102; The order corresponding to the basic transformation unit, including .

[0038] In this embodiment, when the order mapping rule is a binary decomposition method, the selected base orders are {π, π / 2, π / 4, π / 8}. Therefore, any target order can be uniquely decomposed into a combination of the above four base orders, thereby achieving 16 equally spaced discrete orders within the range of 0 to 2π, with an order resolution of π / 8. This decomposition method ensures both the integrity of the coverage and reduces the number of cascaded levels. Figure 2 In the example above, when the target order is 13π / 8, the binary decomposition result is: The corresponding optical implementation device configuration is as follows: Level 1 cross-state access. Unit, second-level direct access Unit, third-level crossover Level 4 cross-connection The final direct-through state is transmitted to the detector, which detects the transformed signal, thereby achieving the target order. The construction of.

[0039] Specifically, compared with other existing solutions, this invention only requires multiple levels of combination to achieve full order coverage. The basic transformation unit has high reuse rate and inherent scalability, requiring only a resolution of [missing information - likely related to order resolution]. The final stage of the implementation device adds one order to the order of The basic transformation unit can realize 0 to 1. Within the range It provides full order coverage for order resolution.

[0040] This scheme uses fidelity as the evaluation criterion to determine the fidelity between the basic transformation unit and the target order matrix (ranging from 0 to 1, with larger values ​​indicating closer similarity to the target matrix, and 1 representing complete consistency between the designed basic transformation unit and the target order matrix). Simulation results demonstrate that the fidelity of the four basic transformation units at a wavelength of 1550nm is greater than 0.995, and the cascaded architecture achieves a fidelity higher than 0.989 for 16 discrete orders (order resolution of π / 8) within the range of 0 to 2π, proving the accuracy of the results.

[0041] Traditional free-space or fiber-optic fractional Fourier transform systems suffer from drawbacks such as large size and non-reconfigurability. In contrast, the optical implementation device proposed in this invention is based on a silicon-based photonics platform, with an overall size only on the micrometer scale. Through a thermo-optically tunable MZI array, the signal path can be flexibly configured to achieve arbitrary fractional Fourier transforms across the entire order range from 0 to 2π, with an order resolution of π / 8. Therefore, this application represents a breakthrough in achieving both "integrability and programmability" simultaneously at the chip scale for the first time, meeting the demands of real-time signal processing.

[0042] Figure 3 In the figure, figures a to d are the micro / nano structure diagrams of the basic transformation unit with orders of π / 8, π / 4, π / 2 and π, respectively; Figure 3 Figure e shows the fidelity and insertion loss curves of the cascaded optical realization device. This application employs an adjoint optimization inverse design method to construct four core basic transformation units, as shown in the figure. Figure 3 As shown in the figure, the simulation results show that the fidelity of a single basic transformation unit at a wavelength of 1550 nm is greater than 0.995, and the overall fidelity of the cascaded 16 discrete orders remains above 0.989. Figure 3 (Middle e blue line). Meanwhile, the insertion loss of a single basic transform unit is only about -1.0 dB to -1.6 dB, far lower than that of traditional coupled waveguide arrays or long fiber implementations, and the insertion loss is less than 6 dB across the entire order range from 0 to 2π. Figure 3 The yellow line in the middle ensures stable and reliable signal transmission quality even during large-scale cascading.

[0043] In this application, the order mapping rule is based on binary decomposition. The optical implementation only requires four basic transformation units {π, π / 2, π / 4, π / 8} to cover 16 discrete orders, significantly reducing system complexity and hardware overhead. Furthermore, this architecture exhibits good scalability; by simply adding finer-resolution basic transformation units (such as π / 16 and π / 32) at the end, higher-precision fractional Fourier transforms can be achieved without requiring a complete overhaul of the existing core network.

[0044] The technical solution of this application, while realizing programmable DFrFT, also possesses good scalability and alternative solutions, mainly including the following two aspects of expansion: expansion in matrix dimension and expansion in order resolution.

[0045] From the perspective of matrix dimension expansion, existing embodiments primarily focus on implementing fractional Fourier transform matrices with N=4 dimensions. However, this approach is not limited to this. In higher-dimensional scenarios, inverse design methods can be used to construct basic transform units with a larger number of input / output ports, such as 6×6, 8×8, or 10×10 matrix units. Simulation results show that even with an increased number of ports, the high-dimensional basic transform units obtained through inverse design still maintain low insertion loss (from −1.01 dB to −1.71 dB) and high fidelity (>0.985). This characteristic allows this approach to be smoothly extended to higher-dimensional photonic signal processing tasks, meeting the high-channel-count computational requirements of complex scenarios.

[0046] Extending the order resolution, this embodiment uses π / 8 as the order resolution, which already covers 16 discrete orders across the entire range [0, 2π]. However, in some applications requiring higher precision (such as synthetic aperture radar imaging and optical filtering), finer order units (e.g., π / 16, π / 32) can be added to the end of the existing architecture. This allows for the achievement of locally higher resolution fractional Fourier transforms while maintaining the original core architecture. This method not only improves the system's adaptability but also avoids overall redesign, thus significantly reducing hardware development costs.

[0047] This invention provides a programmable optical implementation device for discrete fractional Fourier transform. The optical implementation device includes an optical interconnect network 101 and a basic transformation unit 102. The optical implementation device is composed of the cascaded optical interconnect network 101 and the basic transformation unit 102. The optical interconnect network 101 includes a Mach-Zehnder interferometer. The basic transformation unit 102 is a basic transformation unit 102 that can implement the same or different fractional Fourier orders. The basic transformation unit 102 is obtained through an inverse design method. The dynamic control of any order of the optical implementation device from 0 to 2π is achieved by controlling the connectivity state of the Mach-Zehnder interferometer array. The basic transformation unit obtained based on the adjoint optimization inverse design method occupies a small physical area on a silicon-based platform. The optical interconnect network 101 is implemented by a basic Mach-Zehnder interferometer, which has the advantage of integrability and supports standard silicon photonics fabrication. The overall size of the optical implementation device is reduced by three orders of magnitude compared to traditional free-space systems. By adjusting the connectivity of the Mach-Zehnder interferometer array, the optical realization device can be dynamically controlled at any order from 0 to 2π, thus enabling programmability of the optical realization device.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A programmable optical implementation device for discrete fractional Fourier transform, characterized in that, include: Optical interconnect networks and basic conversion units; The optical realization device consists of an optical interconnection network and multiple cascaded basic transformation units; The optical interconnect network includes: a Mach-Zehnder interferometer; the basic transformation unit is a basic transformation unit that realizes the same or different fractional Fourier orders; The basic transformation unit is obtained through inverse design; the dynamic adjustment of the optical realization device from any order between 0 and 2π is achieved by controlling the connectivity state of the Mach-Zehnder interferometer array.

2. The programmable discrete fractional Fourier transform optical implementation device according to claim 1, characterized in that, The basic transformation unit is obtained through an inverse design method, which includes generating the basic transformation unit based on electromagnetic simulation and regular constraints using a dielectric constant parameterized model.

3. The programmable discrete fractional Fourier transform optical implementation device according to claim 1, characterized in that, The dynamic control of the optical realization device from any order between 0 and 2π is achieved by controlling the connectivity state of the Mach-Zehnder interferometer array, including: Based on the target order of the optical realization device, the combination relationship of multiple basic transformation units is determined; wherein, the combination relationship is realized based on the principle of order additivity; The connectivity state of the Mach-Zehnder interferometer array is controlled according to the aforementioned combination relationship.

4. The programmable discrete fractional Fourier transform optical implementation device according to claim 3, characterized in that, The combination relationship includes the configuration states of multiple basic transformation units: the configuration state is either required or not required; the adjustment of the connectivity state of the Mach-Zehnder interferometer array according to the combination relationship includes: When the configuration state of the basic transformation unit is required, the connectivity state of the previous Mach-Zehnder interferometer array set in the basic transformation unit is adjusted to a through state or a cross state to pass through the basic transformation unit. When the configuration state of the basic transformation unit is not required, the connectivity state of the previous Mach-Zehnder interferometer array set in the basic transformation unit is adjusted to a through state or a cross state to bypass the basic transformation unit.

5. The programmable discrete fractional Fourier transform optical implementation device according to claim 1, characterized in that, The optical interconnect network further includes: a first phase shifter and a second phase shifter; The array configuration of multiple sets of the Mach-Zehnder interferometers is set up by the first phase shifter, the second phase shifter, and two multimode interferometers.

6. The programmable discrete fractional Fourier transform optical implementation device according to claim 5, characterized in that, The optical implementation device consists of a cascaded optical interconnect network and basic transformation units, including: The optical realization device consists of an array of multiple Mach-Zehnder interferometers and multiple basic transformation units of different orders; After the input signal enters from the optical realization device, the passage state of the input signal is determined by the array routing of multiple sets of Mach-Zehnder interferometers; the order of the output signal is determined by multiple basic transformation units of different orders and order mapping rules.

7. The programmable discrete fractional Fourier transform optical implementation device according to claim 6, characterized in that, The order mapping rule is implemented through the following formula: in, For the target order, For binary selection coefficients; M is the cascade series. This is the nth basic transformation unit; The order corresponding to the basic transformation unit, including .

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