Generating multiple pulse trains from micro-comb laser

Abstract

A method and system, the method comprising: obtaining a plurality of coherent subcarriers, each coherent subcarrier of the plurality of coherent subcarriers having a subcarrier frequency from a set of subcarrier frequencies, where the set of subcarrier frequencies is equally spaced; filtering a first group of subcarriers with continuous frequencies in the subcarrier frequency set so as to obtain a first equidistant pulse sequence in a time domain; and filtering a second group of subcarriers having consecutive frequencies in the set of subcarrier frequencies, thereby obtaining a second equidistant pulse sequence in the time domain, where the second group is different from the first group, thereby obtaining at least two equidistant time domain pulse sequences, the at least two equidistant time domain pulse sequences have different wavelengths.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 484,226, filed on February 10, 2023, and entitled “Generating a Plurality of PulseTrains from a Micro Comb Laser,” which is incorporated herein by reference in its entirety without disclaimer. Technical Field

[0003] The present disclosure relates generally to using a comb laser source, and in particular to using a comb laser source to generate and use multiple equidistant time-domain pulse trains. Background Art

[0004] A frequency comb is a laser source whose spectrum consists of a series of discrete, equally spaced frequency lines.

[0005] The frequency domain representation of a perfect frequency comb is a series of frequencies according to f0=f0+nf r The spaced delta function, where n is an integer, f r is the comb spacing, which is equal to the repetition frequency or alternatively the modulation frequency of the mode-locked laser, and f0 is the carrier offset frequency, which is lower than f r .

[0006] Comb lasers are implemented in a variety of ways. Two types of comb lasers include semiconductor mode-locked lasers made of semiconductors and having a saturable absorber region, and microring comb lasers that utilize the nonlinear effects of microrings. These comb lasers are collectively referred to as microcomb lasers.

[0007] Now refer to Figure 1 , Figure 1 A schematic diagram of the output of a micro-comb laser is shown, comprising a sequence of equidistant coherent photon carriers, as used in some exemplary embodiments of the present disclosure.

[0008] The output includes a plurality of subcarriers, such as subcarriers 104, 108, 112, and 116, each subcarrier having a subcarrier frequency, wherein the subcarrier frequencies are equally spaced, that is, the frequency spacing between any two consecutive subcarriers is constant. Figure 1 In the example of FIG. 5 , the frequencies are equally spaced within a range of about 1530 to about 1630. Figure 1 Noise 120 is also shown, the amplitude of which is significantly lower than the amplitude of the primary subcarrier.

[0009] Although Figure 1A wavelength range of approximately 1530 nm to 1630 nm is shown, but this is only an example, and other wavelength ranges can be generated by appropriate design of the microring and distributed feedback (DFB) laser source. For example, an O-band DFB laser source can generate a wavelength range of 1270 nm to 1330 nm.

[0010] Now refer to Figure 2 , Figure 2 A schematic diagram of an exemplary micro-ring comb laser system as used in some exemplary embodiments of the present disclosure is shown.

[0011] The system includes a DFB laser source 200 that emits light 204 at a predetermined frequency. The light is coupled to an integrated photonic circuit via an optical coupler and then transmitted through a waveguide 216, which is preferably an ultra-low loss waveguide.

[0012] The light is coupled to a microring resonator (MRR), generally designated 206. The MRR 206 comprises a microresonator ring 208 and a thermal heater ring 212 for heating the microresonator ring 208 and thereby fine-tuning the resonant frequency of the microresonator ring 208 to the frequency of the light source (200). It will be appreciated that the ring 208 resonates at a wavelength such that its circumference divided by the wavelength is an integer, i.e., (2*π*r) / λ=N, where r is the ring radius and λ is the wavelength of the light 204. Therefore, in order to make the ring resonate at a certain wavelength, its circumference needs to be adjusted to correspond to that wavelength, wherein this adjustment can be performed by the thermal heater ring 212.

[0013] Therefore, the output light 216 includes subcarriers of equidistant frequencies, such as Figure 1 shown.

[0014] Comb lasers are used for various applications in communications, serving as sources for generating multiple wavelengths. In some exemplary applications, the wavelengths can be separated and one or more of them modulated, enabling the transmission of large amounts of data at high rates. Summary of the Invention

[0015] An exemplary embodiment of the disclosed subject matter is a method comprising: obtaining a plurality of coherent subcarriers, each coherent subcarrier in the plurality of coherent subcarriers having a subcarrier frequency from a set of subcarrier frequencies, wherein the set of subcarrier frequencies is equally spaced; filtering a first group of subcarriers in the set of subcarrier frequencies having consecutive frequencies to obtain a first equidistant pulse sequence in the time domain; and filtering a second group of subcarriers in the set of subcarrier frequencies having consecutive frequencies to obtain a second equidistant pulse sequence in the time domain, wherein the second group is different from the first group, thereby obtaining at least two equidistant time-domain pulse sequences, the at least two equidistant time-domain pulse sequences having different wavelengths. In the method, a first wavelength of the first equidistant time-domain pulse sequence in the time domain optionally depends on a center frequency of the first group of subcarriers, and a second wavelength of the second equidistant time-domain pulse sequence depends on a center frequency of the second group of subcarriers. In the method, the first group of subcarriers and the second group of subcarriers optionally do not have any common subcarriers. In this method, a smaller number of subcarriers in the first group of subcarriers may optionally provide wider pulses in a first equidistant time-domain pulse sequence; a larger number of subcarriers in the first group of continuous lightwaves may optionally provide narrower pulses in the first equidistant time-domain pulse sequence; a smaller number of subcarriers in the second group of continuous lightwaves may optionally provide wider pulses in a second equidistant time-domain pulse sequence; and a larger number of subcarriers in the second group of continuous lightwaves may optionally provide narrower pulses in the second equidistant time-domain pulse sequence. The method may further include: providing the first equidistant time-domain pulse sequence to a first chirped Bragg grating filter to obtain a shaped first equidistant time-domain pulse sequence; or providing the second equidistant time-domain pulse sequence to a second chirped Bragg grating filter to obtain a shaped second equidistant time-domain pulse sequence. The method may further include: transmitting the shaped first equidistant time-domain pulse sequence or the shaped second equidistant time-domain pulse sequence to a semiconductor optical amplifier (SOA) for amplification after modulation. The method may further include: modulating the shaped first equidistant time-domain pulse sequence or the shaped second equidistant time-domain pulse sequence. The method may further include: transmitting the first equidistant time-domain pulse sequence or the second equidistant time-domain pulse sequence to an SOA after modulation for amplification. The method may further include: using the first equidistant time-domain pulse sequence or the second equidistant time-domain pulse sequence as an optical clock. The method may further include: providing the first equidistant time-domain pulse sequence to a first variable optical attenuator (VOA) to obtain a first high-rate single photon sequence at the wavelength of the first equidistant time-domain pulse sequence; or providing the second equidistant time-domain pulse sequence to a second VOA to obtain a second high-rate single photon sequence at the wavelength of the second equidistant time-domain pulse sequence. The method may further include: using the first high-rate single photon sequence or the second high-rate single photon sequence as a quantum bit source.In the method, each of the first set of continuous light waves and the second set of continuous light waves optionally includes at least 8 light waves.

[0016] Another exemplary embodiment of the disclosed subject matter is a system comprising: a laser source for emitting a light wave; a mechanism for generating a plurality of coherent subcarriers from the light wave, each of the plurality of coherent subcarriers having a subcarrier frequency from a set of carrier frequencies, wherein the set of subcarrier frequencies is equally spaced; at least a first filter for filtering a first group of subcarriers having consecutive frequencies in the set of subcarrier frequencies to obtain a first equidistant pulse sequence in the time domain; at least a second filter for filtering a second group of subcarriers having consecutive frequencies in the set of subcarrier frequencies to obtain a second equidistant pulse sequence in the time domain; and at least one selected from the group consisting of: Item: an electro-optical converter and a semiconductor optical amplifier, the electro-optical converter being configured to convert electrical data into optical data and modulate the first equidistant pulse sequence or the second equidistant pulse sequence, the semiconductor optical amplifier being configured to amplify the light wave to obtain at least one optical data signal; a variable optical attenuator being configured to convert the first equidistant pulse sequence or the second equidistant pulse sequence into a single photon sequence; and a semiconductor optical amplifier being configured to amplify the light wave to generate an optical clock signal; and an arrayed waveguide grating being configured to multiplex the at least one optical data signal, the single photon sequence, or the optical clock signal into a unified light beam. The system may further include a receiver system comprising: an arrayed waveguide grating for demultiplexing the unified light beam; and at least one item selected from the following: a photodetector and a transimpedance amplifier being configured to receive a pulse train demultiplexed from the unified light beam, the transimpedance amplifier being configured to obtain electronic data or clock pulses; and a single-photon avalanche photodetector being configured to obtain a single-photon sequence. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The subject matter of the present disclosure will be more fully understood and appreciated through the following detailed description presented in conjunction with the accompanying drawings, in which corresponding or similar numbers or symbols represent corresponding or similar components. Unless otherwise specified, the accompanying drawings provide exemplary embodiments or aspects of the present disclosure and do not limit the scope of the present disclosure. In the drawings:

[0018] Figure 1 is a schematic diagram of the output of a micro-comb laser as used in some embodiments of the present disclosure, the output comprising a sequence of equidistant optical subcarriers;

[0019] Figure 2is a schematic diagram of an exemplary micro-ring comb laser system as used in some exemplary embodiments of the present disclosure;

[0020] Figure 3A and Figure 3B shows selected groups of consecutive subcarriers according to some exemplary embodiments of the present disclosure;

[0021] Figure 4A and Figure 4B According to some exemplary embodiments of the present disclosure, Figure 3A and Figure 3B The pulse train generated by the grouped subcarriers;

[0022] Figures 5A to 5E shows the pulse trains obtained from grouping subcarriers with different numbers of harmonics;

[0023] Figure 6 is a schematic diagram of a sliced ​​micro-ring comb laser according to some exemplary embodiments of the present disclosure;

[0024] Figure 7 is a schematic block diagram of using multiple equidistant pulse trains in a system according to some exemplary embodiments of the present disclosure;

[0025] Figure 8 is a schematic block diagram of a receiver system according to some exemplary embodiments of the present disclosure; and

[0026] Figure 9 is a flow chart of a method for generating and using a pulse train from a micro-comb laser according to some exemplary embodiments of the present disclosure. DETAILED DESCRIPTION

[0027] A technical problem to be solved by the present disclosure is the need to generate multiple accurate high repetition rate equidistant pulse trains with different center frequencies.

[0028] Another technical problem to be solved by the present disclosure is the need to implement multiple uses of equidistant pulse trains with high reliability, such as data transmission, co-packaged optical devices, machine learning, spectroscopy, etc., where in some embodiments it may be important that the pulse trains have exactly the same repetition rate.

[0029] One technical solution of the present disclosure involves obtaining multiple coherent light waves (also called subcarriers) with equally spaced frequencies, such as those emitted by a single micro-comb laser. These light waves can be fed into an optical splitter to split the power of a beam into multiple beams, allowing each beam to be processed individually and simultaneously.

[0030] A first group of subcarriers (a non-limiting example of about 8 to about 32 consecutive subcarriers output by the optical splitter) from the plurality of subcarriers may be filtered, for example, by a first optical filter.

[0031] The set of subcarriers in the first group forms an equidistant pulse train in the time domain, wherein the pulses in the pulse train have a wavelength range whose center wavelength corresponds to the center frequency of the first optical filter.

[0032] The second group of subcarriers (eg, as a non-limiting example, about 8 to about 32 consecutive subcarriers output by the optical splitter) may be filtered from the plurality of subcarriers by a second optical filter. The first group of subcarriers and the second group of subcarriers may have no common subcarriers.

[0033] The set of subcarriers in the second group forms a second equidistant pulse train in the time domain, wherein the pulses in the second pulse train have a wavelength range whose central wavelength corresponds to the central frequency of the second optical filter.

[0034] Therefore, the center wavelength of the first pulse train and the center wavelength of the second pulse train are different. However, the pulse rate in the two pulse trains is equal, and the pulse rate is determined by the spacing between consecutive frequencies in the obtained multiple subcarriers, and is therefore equal for the first pulse train and the second pulse train.

[0035] Additional groups of subcarriers can be separated from the received set of subcarriers. These groups of subcarriers provide pulse trains in the time domain, each with a different wavelength because the center wavelength of each pulse train is equal to the center wavelength of the group of subcarriers that generated it. It will be appreciated that all pulse trains are equidistant and that the time difference between all consecutive pulses is the same.

[0036] It should also be understood that the width of the pulses in each pulse train depends on the number of consecutive subcarriers that make up the pulse train in the time domain. Therefore, a greater number of subcarriers in the group results in a narrower width of each pulse in the pulse train. This is because short pulses vary faster than long pulses, so short pulses include a greater frequency, which means that higher bandwidths will have a greater frequency and lower bandwidths will have a smaller frequency. Therefore, the number of groups and the number of subcarriers in each group need to be selected so that the pulses of different pulse trains overlap or do not overlap as needed. Figure 1 As can be seen, the emission spectrum of the microring comb laser is not uniform but rather bell-shaped. By selecting an appropriate range from the spectrum, the shape and width of the individual pulses in each pulse train can be modified as desired while maintaining the same repetition rate. It is understood that by selecting a limited number of consecutive frequencies, the amplitude of the selected frequencies will be within a relatively small range.

[0037] One or more of the pulse trains may be shaped to obtain a desired pulse shape, for example using a chirped Bragg grating filter.

[0038] Another technical solution of the present disclosure involves using one or more of the pulse trains as an optical clock due to its accurate high repetition rate.

[0039] Yet another technical solution of the present disclosure involves using one or more pulse trains in a pulse train to carry data, and modulating each pulse train according to digital data or analog data to generate one or more modulated high repetition rate signals.

[0040] Another technical solution disclosed herein involves attenuating the pulses of a pulse train to reduce the number of photons in each pulse to single photons of the same color as the associated pulse, thereby generating a high-rate single-photon sequence at the wavelength of the pulse train, which can serve as a source of quantum bit photons.

[0041] Yet another technical solution of the present disclosure involves time domain multiplexing of different pulse trains with different central wavelengths, thereby generating a higher data rate and achieving time and frequency separation of different channels.

[0042] Another technical solution of the present disclosure involves multiplexing one or more modulated pulse trains, and / or optical clocks, and / or one or more single photon sequences carrying different types of data or data from different sources, all of which have the same repetition rate. Arrayed waveguide gratings (AWGs) can be used for combination. These signals can then be transmitted over a single medium and demultiplexed at the receiving end to retrieve the clock, all data signals, and the single photon sequence.

[0043] One technical effect of the present disclosure involves using a micro-comb laser or a semiconductor mode-locked laser (collectively referred to as a micro-comb laser) to generate equidistant temporal pulse trains with different center frequencies using a single micro-ring comb laser. The pulse train is easy to generate, and the time difference is extremely accurate.

[0044] Another technical effect of the present disclosure relates to using each pulse train for purposes such as carrying digital data, generating a sequence of single photons, or simply as an optical clock.

[0045] Another technical effect of the present disclosure relates to combining the use of two or more of the above-mentioned pulse trains, transmitting them over a single medium and utilizing their constant repetition rate.

[0046] Now refer to Figure 3A and Figure 3B , Figure 3A and Figure 3B Selected groups of contiguous subcarriers are shown according to some exemplary embodiments of the present disclosure.

[0047] Figure 3A and Figure 3B A graph 300 is shown of wavelengths emitted by a micro-comb laser, such as wavelengths 304, 308, and 312. The frequencies corresponding to these wavelengths are equidistant, i.e., the difference between any two consecutive frequencies is constant. It will be appreciated that while all amplitudes are shown as being the same, this is not always the case. For example, Figure 1 As shown, consecutive subcarriers are grouped together with amplitudes that are close, but not necessarily the same.

[0048] A first set of continuous light waves may be selected, such as set 320 comprising 16 wavelengths. The light waves in set 320 have wavelengths in the range between λ1-Δλ1 and λ1+Δλ1, and have an average wavelength of λ1.

[0049] The Fourier transform of the collection of light waves provides a pulse train, as can be understood from the following formula:

[0050]

[0051] Therefore, the sum of equally spaced frequencies in the frequency domain is converted into a pulse train in the time domain.

[0052] Figure 4A Shown with Figure 3A The pulse train corresponding to the selected subcarrier in the 400 signal includes a typical pulse 404, wherein the time difference between any two consecutive pulses is constant. For example, the time difference between pulses 412 and 416 is equal to the time difference between pulses 404 and 408.

[0053] Similarly, a second set of continuous light waves can be selected, such as Figure 3B The inclusion range in λ M -Δλ M and λ M +Δλ M 16 wavelengths between and with a central wavelength of λ M The group 324 also provides Figure 4B The pulse train 420 is shown. Note that the first group and the second group are different, ie, do not contain the same set of subcarriers.

[0054] Each burst has a unique wavelength that is the same as the center frequency, eg, the average frequency of the corresponding group of subcarriers, such as for a burst based on the subcarriers in group 320. Figure 4A The wavelength of the pulse train is λ1, for the subcarriers in group 324 Figure 4B The wavelength of the pulse train is λM .

[0055] It can be understood that the time difference between consecutive pulses in the two pulse trains is equal because this time difference is affected by the distance between the frequencies in the set of subcarriers output by the micro-comb laser.

[0056] although Figure 3A 、 Figure 3B 、 Figure 4A and Figure 4B It refers to two groups of subcarriers generating two pulse trains, but the present disclosure is not limited to two groups, but any number of groups can be generated to form a corresponding number of pulse trains.

[0057] The width of the pulses in each burst depends on the number of subcarriers in the selected group, so groups with more wavelengths produce narrower pulses, and groups with fewer wavelengths produce wider pulses. At one extreme, using a single group of all wavelengths yields the narrowest pulses, but this only generates a single burst. At the other extreme, generating a burst for each individual wavelength results in overlapping, wide pulses that are nearly indistinguishable.

[0058] In some embodiments, the groups can be selected to be mutually exclusive, i.e., not have any common wavelengths. This can be beneficial because it allows each pulse to have maximum power without having to split the power between pulses belonging to different pulse trains.

[0059] Now refer to Figures 5A to 5E , Figures 5A to 5E Shown is a pulse train obtained when a pulse train is generated by grouping subcarriers having different numbers (N) of frequencies starting from zero frequency (DC) to higher harmonics. Figures 5A to 5E The example of involves a baseband signal at zero frequency. However, the same effect is also demonstrated for a bandpass signal located around the DFB laser frequency, such as Figure 1 Therefore, Figure 5A The graph 500 in FIG. 1 shows a zero pulse train when the light wave is not filtered. Figure 5B Graph 504 in FIG. 5 shows a pulse train of a single wavelength, Figure 5C Graph 508 in FIG. 5 shows the pulse train when filtering two wavelengths, Figure 5D Graph 512 in FIG. 5 shows the pulse train when filtering three wavelengths, and Figure 5E Graph 508 in FIG. 5 shows the pulse train when filtering eight wavelengths.

[0060] It can be seen that as the number of subcarriers increases, the highest pulse becomes narrower and more intense relative to the sidelobes while maintaining the repetition rate.

[0061] Now refer to Figure 6 , Figure 6 Schematic diagram of a sliced ​​micro-ring comb laser according to some exemplary embodiments of the present disclosure is shown.

[0062] DFB laser 200, light 204, MRM 206 including microresonator ring 208 and thermal heater ring 212, and output light 216 are combined as described above. Figure 2 As stated.

[0063] Output light 216 comprising multiple frequencies conforming to the diameter of microresonator ring 208 can be provided to optical splitter 604 to split the power of the beam into multiple beams so that each beam can be individually processed simultaneously.

[0064] Each split beam passes through a filter, such as tunable optical bandpass filter 1 (608) or tunable optical bandpass filter 2 (620). The filter outputs a specific frequency, such as group 320 having a center frequency λ1 or group 324 having a center frequency λ M As described above, each frequency in the selected grouped frequencies forms a pulse train in the time domain, and the pulses in each pulse train have a center frequency corresponding to the grouped frequency.

[0065] Each of the bandpass filters may be a discrete component or may be implemented in an integrated photonic platform such as silicon, silicon nitride, or other materials.

[0066] Each pulse train may pass through a chirped Bragg grating filter, for example, for the first pulse train, it may pass through chirped Bragg grating filter 1 (612), and for the second pulse train, it may pass through chirped Bragg grating filter 2 (624).

[0067] Chirped Bragg grating filters can shape the pulses in the pulse train into a desired shape. Additionally or alternatively, pulse shaping can also be performed through high-dispersion optical fibers.

[0068] In some embodiments, chirped Bragg grating filters can be implemented using optical fiber or integrated photonics such as, but not limited to, silicon photonics or silicon nitrite.

[0069] Now refer to Figure 7 , Figure 7 A schematic block diagram of a system for using multiple equidistant pulse trains according to some exemplary embodiments of the present disclosure is shown.

[0070] The system is generally designated 700 and is configured to generate a laser beam from a micro-comb laser such as Figure 6 The sliced ​​micro-ring comb laser 600 described in receives multiple equidistant pulse trains.

[0071] In some embodiments, one or more pulse trains (such as pulse train 701 or pulse train 702) can be encoded with digital information or analog information. For example, in the digital form, digital data 1 (704) can be converted from digital data to optical data and used to modulate pulse train 701 through electro-optical (E / O) converter 708 to obtain modulated pulse train 712. Similarly, digital data M (720) can be converted from digital data to optical data and used to modulate pulse train 702 through electro-optical (E / O) converter 724 to obtain modulated pulse train 728. E / O converter 708 or E / O converter 724 can be a Mach-Zehnder modulator, an electro-absorption modulator, a micro-ring modulator, a plasmon modulator, or any other type. E / O converter 708 or E / O converter 724 can be a discrete device or can be implemented on any integrated photonic platform to obtain modulated pulse train 712 or 728.

[0072] Each modulated optical beam (such as modulated pulse train 712 or modulated pulse train 728) can be input into a semiconductor optical amplifier (SOA), such as for modulated pulse train 712, it can be input into SOA716, or for modulated pulse train 728, it can be input into SOA732.

[0073] The SOA716 or SOA732 can amplify the pulse to the required level.

[0074] Another pulse train (such as pulse train 736) can be provided to a variable optical attenuator (VOA) (such as VOA 740) for attenuating the pulses into single photons, thereby generating a sequence of single photons. This sequence can have a high rate, equal to the repetition rate of the pulse train, such as 50 GHz, 100 GHz, 200 GHz, etc. The required repetition rate can be achieved by appropriate size of the microring. This sequence of single photons can be used as a qubit source.

[0075] Another pulse train, such as pulse train 744, may or may not be provided unmodulated to SOA 748, which may amplify the pulses, which may then be used as an optical clock due to the accuracy of the pulse train.

[0076] It will be appreciated that while only two pulse trains are shown modulated with electrical data, the system is not limited to two such pulse trains, and any number of pulse trains may be used, as determined by the desired pulse width. It will also be appreciated that multiple single photon trains may be generated, each with a different wavelength, and multiple electrical clocks may also be implemented, although this may result in unnecessary redundancy.

[0077] Some or all of the above mentioned outputs may be fed into an arrayed waveguide grating (AWG) 752 where they may be multiplexed into an output unified light beam 756 .

[0078] Now refer to Figure 8 , Figure 8 A schematic block diagram of a receiver system for separating and using individual components of output light 756 according to some exemplary embodiments of the present disclosure is shown.

[0079] The unified light beam 756 output from the AWG 756 on the transmitter side includes one or more data streams, an optical clock, and / or one or more single photon sequences that can be used as quantum data and quantum keys. The unified light beam can be received by the AWG 800 on the receiver side, which can demultiplex the unified light beam into individual components.

[0080] Thus, AWG 800 may output multiple pulse trains, such as pulse train 808 and pulse train 824. Each pulse train may be provided to a corresponding photodetector, such as photodetector 804 for pulse train 808 or photodetector 820 for pulse train 824.

[0081] The photodetector may output an electrical signal according to the input optical signal, such as the electrical signal 808 output by the photodetector 804 or the electrical signal 824 output by the photodetector 820 .

[0082] In some embodiments, each electrical signal can be provided to a corresponding transimpedance amplifier, such as transimpedance amplifier 812 for electrical signal 808 or transimpedance amplifier 828 for electrical signal 824, and the transimpedance amplifier can output an amplified electrical signal, such as electrical signal 816 or electrical signal 832. These electrical signals and the amplified electrical signals can carry optical wave data output by the laser source and the sliced ​​micro-comb laser (e.g., sliced ​​micro-ring comb laser 600), such as data 1 (704), data M (720), or additional data. Thus, electrical signal 816 can carry data 1 (704), and electrical signal 832 can carry data M (720).

[0083] In some embodiments, the AWG 800 may also output a sequence of single photons 836 , which may be provided to a single-photon avalanche photodetector (SPAD) 840 , which may detect the single photons and output corresponding electrical signals 844 .

[0084] In some embodiments, the AWG 800 may also output one or more additional pulse trains that do not yet encode data, such as pulse train 836. The one or more pulse trains (such as pulse train 836) may also be fed into a photodetector (such as photodetector 848) to output an electrical signal 852, which may be amplified by a transimpedance amplifier 856 to output a signal 860, which may be used as a clock signal 864.

[0085] Thus, the same microring comb laser can be used to generate various signals: one or more pulse trains for data transmission, pulse trains for clocks for various purposes, and one or more single-photon sources, creating a multifunctional light source from a single microring comb laser.

[0086] It will be appreciated that since all outputs of the AWG 800 have the same repetition rate, the clock 864 can be used to synchronize all other outputs of the system, including data 1 ( 704 ), data M ( 720 ), and the electrical signal 844 .

[0087] It will be understood that the present disclosure is not limited to two data streams, one photon sequence, and one clock signal, but may provide any combination of any number of the above.

[0088] Now refer to Figure 9 , Figure 9 A flow chart illustrating a method for generating and using a pulse train from a micro-comb laser according to some exemplary embodiments of the present disclosure is shown.

[0089] At step 900, a plurality of light waves of equally spaced frequencies may be received from a source such as a micro-comb laser.

[0090] At step 904, a first set of the continuous light waves may be filtered, which when examined in the time domain provides an accurate first equidistant (in time) pulse train.

[0091] At step 908, a second set of the continuous light waves may be filtered to provide an accurate second equidistant (in time) pulse train when the second set of the continuous light waves is examined in the time domain.

[0092] At step 912, any one or more of the pulse trains may be used as a clock for encoding data, generating a sequence of single photons, or other purposes.

[0093] The present invention may be a system, method and / or computer program product. The computer program product may include one or more computer-readable storage media having computer-readable program instructions for causing a processor to perform various aspects of the present invention.

[0094] A computer-readable storage medium can be a tangible device that can save and store instructions for use by an instruction execution device. A computer-readable storage medium can be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the above devices. A non-exhaustive list of more specific examples of computer-readable storage media includes the following: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disc (DVD), a memory stick, a floppy disk, a mechanical encoding device (such as a punched card or a raised structure with recorded instructions in the groove), and any suitable combination of the above devices. As used herein, a computer-readable storage medium should not be interpreted as a transient signal itself, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagated through a waveguide or other transmission medium (for example, a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0095] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to a corresponding computing / processing device, or downloaded to an external computer or external storage device via a network (e.g., the Internet, a local area network, a wide area network, and / or a wireless network). The network can include copper transmission cables, optical transmission fibers, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions to be stored in a computer-readable storage medium within the corresponding computing / processing device.

[0096] The computer-readable program instructions for performing the operation of the present invention can be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages ​​(such as " C ", C#, C++, Java, Phyton, Smalltalk or other languages). The computer-readable program instructions can be performed completely on the user's computer, partly on the user's computer (performed as an independent software package), partly on the user's computer and partly on a remote computer, or completely on a remote computer or server. In the latter case, the remote computer can be connected to the user's computer through any type of network (including local area network (LAN) or wide area network (WAN)), or can be connected to an external computer (for example, being connected to the Internet by an internet service provider). In some embodiments, the electronic circuit comprising for example programmable logic circuit, field programmable gate array (FPGA) or programmable logic array (PLA) can be personalized to the electronic circuit by utilizing the state information of the computer-readable program instructions, thereby executing the computer-readable program instructions, to perform various aspects of the present invention.

[0097] Various aspects of the present invention are described herein with reference to the flow charts and / or block diagrams of the methods, devices (systems) and computer program products according to embodiments of the present invention. It will be understood that each block in the flow charts and / or block diagrams and the combination of blocks in the flow charts and / or block diagrams can be implemented by computer-readable program instructions.

[0098] The flow chart and block diagram in the figure show the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present invention.In this respect, each block in the flow chart or block diagram can represent the part of a module, program segment or instruction, and the part of this instruction includes one or more executable instructions for realizing a specified logical function.In some alternative implementations, the function marked in the block can occur in a sequence different from that marked in the accompanying drawings.For example, the two blocks shown in succession can actually be performed substantially simultaneously, or sometimes these blocks can be performed in reverse order, specifically depending on the function involved.It will also be noted that each block in the block diagram and / or flow chart, and the combination of blocks in the block diagram and / or flow chart can be realized by a hardware-based dedicated system that performs a specified function or action or performs a combination of dedicated hardware and computer instructions.

[0099] The terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the present invention. As used herein, the singular forms "a", "an", and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It will also be understood that the terms "comprises" and / or "comprising" used in this specification specify the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or combinations thereof.

[0100] The corresponding structures, materials, acts, and equivalents of all means or steps and functions in the appended claims, and equivalents thereof, are intended to include any structure, material, or act for performing the function in combination with other claimed elements, as claimed in the specific claims. The description of the invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or to limit the invention to the form disclosed. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the invention. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, and to enable others skilled in the art to understand the various embodiments of the invention and various modifications as are suitable for the particular use contemplated.

Claims

1. A method comprising: Obtaining a plurality of coherent subcarriers, each coherent subcarrier in the plurality of coherent subcarriers having a subcarrier frequency from a set of subcarrier frequencies, wherein the set of subcarrier frequencies are equally spaced; filtering a first group of subcarriers having continuous frequencies in the subcarrier frequency set to obtain a first equidistant pulse sequence in the time domain; and filtering a second group of subcarriers having consecutive frequencies in the set of carrier frequencies to obtain a second equidistant pulse sequence in the time domain, wherein the second group is different from the first group, Thereby, at least two equidistant time-domain pulse sequences are obtained, and the at least two equidistant time-domain pulse sequences have different wavelengths.

2. The method according to claim 1, wherein A first wavelength of the first equidistant pulse train in the time domain depends on a center frequency of the first group of subcarriers, and a second wavelength of the second equidistant time-domain pulse train depends on a center frequency of the second group of subcarriers.

3. The method according to claim 1, wherein The first group of subcarriers and the second group of subcarriers do not have any common subcarriers.

4. The method according to claim 1, wherein A smaller number of subcarriers in the first set of subcarriers provides wider pulses in the first equidistant time-domain pulse sequence, The larger number of subcarriers in the first set of continuous light waves provides narrower pulses in the first equidistant time-domain pulse sequence. The smaller number of subcarriers in the second set of continuous light waves provides wider pulses in the second equidistant time-domain pulse train, and A greater number of subcarriers in the second set of continuous light waves provides narrower pulses in the second equidistant time-domain pulse train.

5. The method according to claim 1, further comprising: The first equidistant time-domain pulse sequence is provided to a first chirped Bragg grating filter to obtain a shaped first equidistant time-domain pulse sequence, or the second equidistant time-domain pulse sequence is provided to a second chirped Bragg grating filter to obtain a shaped second equidistant time-domain pulse sequence.

6. The method according to claim 5, further comprising: The shaped first equidistant time-domain pulse sequence or the shaped second equidistant time-domain pulse sequence is transmitted to a semiconductor optical amplifier (SOA) for amplification after being modulated.

7. The method according to claim 5, further comprising: The shaped first equidistant time-domain pulse sequence or the shaped second equidistant time-domain pulse sequence is modulated.

8. The method according to claim 7, further comprising: The first equidistant time-domain pulse sequence or the second equidistant time-domain pulse sequence is transmitted to the SOA after being modulated for amplification.

9. The method according to claim 1, further comprising: The first equidistant time-domain pulse sequence or the second equidistant time-domain pulse sequence is used as an optical clock.

10. The method according to claim 1, further comprising: The first equidistant time-domain pulse sequence is provided to a first variable optical attenuator (VOA) to obtain a first high-rate single-photon sequence at the wavelength of the first equidistant time-domain pulse sequence, or the second equidistant time-domain pulse sequence is provided to a second VOA to obtain a second high-rate single-photon sequence at the wavelength of the second equidistant time-domain pulse sequence.

11. The method according to claim 10, further comprising: The first high-rate single-photon sequence or the second high-rate single-photon sequence is used as a quantum bit source.

12. The method according to claim 1, wherein Each of the first set of continuous light waves and the second set of continuous light waves includes at least 8 light waves.

13. A system comprising: a laser source, the laser source being used to emit light waves; means for generating a plurality of coherent subcarriers from the lightwave, each coherent subcarrier in the plurality of coherent subcarriers having a subcarrier frequency from a set of carrier frequencies, wherein the set of subcarrier frequencies are equally spaced; at least a first filter for filtering a first group of subcarriers having consecutive frequencies in the set of subcarrier frequencies to obtain a first equidistant pulse sequence in the time domain; at least a second filter for filtering a second group of subcarriers having consecutive frequencies in the set of subcarrier frequencies, thereby obtaining a second equidistant pulse sequence in the time domain; At least one selected from the following: an electro-optical converter and a semiconductor optical amplifier, wherein the electro-optical converter is used to convert electrical data into optical data and modulate the first equidistant pulse sequence or the second equidistant pulse sequence, and the semiconductor optical amplifier is used to amplify the light wave to obtain at least one optical data signal; a variable optical attenuator, configured to convert the first equidistant pulse sequence or the second equidistant pulse sequence into a single photon sequence; and a semiconductor optical amplifier for amplifying the light wave to generate an optical clock signal, and An arrayed waveguide grating is used to multiplex the at least one optical data signal, the single photon sequence or the optical clock signal into a unified light beam.

14. The system of claim 13, further comprising a receiver system comprising: an arrayed waveguide grating for demultiplexing the unified light beam; as well as At least one selected from the following: a photodetector and a transimpedance amplifier, the photodetector being configured to receive a pulse train demultiplexed from the unified light beam, and the transimpedance amplifier being configured to obtain electronic data or clock pulses; as well as A single-photon avalanche photodetector is provided, wherein the single-photon avalanche photodetector is used to obtain a single-photon sequence.

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