Arbitrary optical pulse pattern generator

Abstract

The generator for generating the optical pulse pattern is the primary laser pulse (LB00 k ), and the light of the primary laser pulse is split into multiple branches (A1, A2) to generate multiple primary optical pulses (LB0 k,1 , LB0 k,2 ) and the modulated optical signal (LB1 k,1 , LB1 k,2 ) are combined to output signal (LB2 k ), and a control unit that outputs a control signal for controlling the optical modulators (MOD1, MOD2) of the branches according to a primary pattern, and the first branch (A1) outputs a first branch primary optical pulse (LB0 k,1 ) to the first modulated optical signal (LB1 k,1 ), and the second branch (A2) has a first optical modulator (MOD1) for forming the first order optical pulse (LB0 k,2 ) to a second modulated optical signal (LB1 k,2 ), the propagation delay of the second branch being different from the propagation delay of the first branch.

Description

[Technical Field]

[0001] Some embodiments relate to generating light pulse patterns. [Background technology]

[0002] It is known to generate arbitrary optical pulse patterns by generating electrical waveforms using an arbitrary electrical pattern generator (APG). The electrical waveform may then be used to control an optical intensity modulator to modulate continuous wave light or pulsed laser light to generate the optical pulse pattern. To generate arbitrary optical pulse patterns at frequencies higher than 10 GHz, an electrical waveform of at least the same frequency must be generated. However, it is difficult or impossible to accurately generate electric arbitrary waveforms at very high frequencies. The generated electric arbitrary waveforms may be noisy due to their high bandwidth. The shape of the optical pulses generated by optical modulators at high frequencies can be strongly affected by noise and / or jitter in the electrical waveform. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention aims to provide an optical pattern generator (APPG) and a method for generating an optical pulse pattern. [Means for solving the problem]

[0004] In order to achieve the above object, the optical pattern generator (OPG1) of the present invention comprises: ·First laser pulse (LB00 k ) and a light source (LS1) that outputs The primary laser pulse (LB00 k ) into multiple branches (A1, A2, A3) to generate multiple first-order optical pulses (LB0 k,1 , LB0k,2 , LB0 k,3 ) and a splitter (SPL1) that outputs A modulated optical signal (LB1 k,1 , LB1 k,2 , LB1 k,3 ) are combined to produce an output signal (LB2 k ), and a combiner (CMB1) that forms a control unit (PG0) that outputs control signals (S1, S2, S3) for controlling the optical modulators (MOD1, MOD2, MOD3) of the branches (A1, A2, A3) according to a primary pattern (PAT0), The first branch (A1) receives the first-order optical pulse (LB0 k,1 ) to the first modulated optical signal (LB1 k,1 a first optical modulator (MOD1) forming a The second branch (A2) receives the first-order optical pulse (LB0 k,2 ) to a second modulated optical signal (LB1 k,2 a second optical modulator (MOD2) forming a The third branch (A3) receives the first-order optical pulse (LB0 k,3 ) to the third modulated optical signal (LB1 k,3 a third optical modulator (MOD3) forming a the propagation delay (d2) of the second branch (A2) is different from the propagation delay (d1) of the first branch (A1); The propagation delay (d3) of the third branch (A3) is different from the propagation delay (d1) of the first branch (A1) and different from the propagation delay (d2) of the second branch (A2).

[0005] Further aspects are defined in the claims.

[0006] The scope of protection sought for various embodiments of the invention is set forth in the independent claims. Embodiments described herein (if any) that do not fall within the scope of the independent claims should be interpreted as examples useful for understanding various embodiments of the invention.

[0007] The device may be an arbitrary optical pulse pattern generator (APPG). The envelope function of the generated pulse sequence may be selectable. The envelope function of the generated pulse sequence may be selectable by a user. The pulse sequence may also be referred to as a pulse pattern.

[0008] The generator may split the light of the primary laser pulse into multiple branches, and each laser pulse may be split into multiple primary light pulses propagating synchronously in each branch of the generator.

[0009] Each branch may comprise an optical waveguide for guiding the primary optical pulse and / or for providing an appropriate (different) propagation delay. The number of branches (M) may be, for example, in the range of 4 to 1024. By using more branches, a higher output pulse repetition rate can be obtained and / or a pulse pattern with higher temporal resolution can be output.

[0010] Each branch may comprise an independently controllable modulator to form a modulated signal from the primary optical pulses. Each branch may have a different propagation delay such that the modulated signal pulses are interleaved when recombined to form the desired output signal. The optical output signal may include a pulse pattern corresponding to the desired primary pattern. The maximum pulse rate of the output signal may be, for example, M times the pulse rate of the laser pulses.

[0011] The generator may operate as a repetition rate multiplication and pulse pattern shaping system, capable of splitting, modulating and combining pulses without substantially changing the pulse quality.

[0012] The device may include a splitter for forming primary optical pulses from laser pulses. The laser pulses may be generated, for example, by a mode-locked laser. Splitting and combining may be implemented using passive optics. Splitting, modulation, and / or combining may be performed without substantially modifying the shape of the optical pulses.

[0013] The modulator in each branch may form a modulated signal from the first-order optical pulse. The modulator may allow the first-order optical pulse to pass through the modulator to the combiner or may prevent the first-order optical pulse from propagating to the combiner. The state of the modulator may be, for example, a pass state or a block state. The modulator may be, for example, a Mach-Zehnder modulator. The state of the modulator may be controlled, for example, by applying a control voltage signal to the modulator. The control voltage signal may include a control signal pulse.

[0014] A control unit may be provided to generate an electrical control signal for the modulator. The control unit may include a memory for storing a primary pattern. The primary pattern may be composed of, for example, a sequence of binary values ​​defining an envelope function of a desired optical pulse pattern. The control unit may include, for example, a programmable gate array (FPGA) for outputting a binary control signal to a driver according to, for example, the values ​​of the primary pattern. (FPGA stands for Field-Programmable Gate Array.) The driver may form a control signal for the modulator based on the binary control signal.

[0015] The optical output of the generator may consist of a sequence of substantially RZ (return-to-zero) optical pulses. The sequence may represent, for example, any binary pattern. The output may be a substantially binary optical signal formed according to a linear pattern. Each output value of the sequence (in quantized time) may be substantially full amplitude or substantially zero. The frequency of the pulses (M·f0) may be, for example, greater than 10 Gbit / s. The shortest time between the rising edges of successive pulses of the output may be, for example, less than 1 ns.

[0016] The base repetition rate (f0) of the primary laser pulses may be, for example, in the range of 1 GHz to 10 GHz. In particular, the base repetition rate (f0) of the primary laser pulses may be, for example, in the range of 2 GHz to 3 GHz. The control electronics may, for example, operate at a frequency equal to the base repetition rate of the primary laser pulses. The maximum pulse repetition rate of the control signal applied to the modulator of the branch may be substantially less than the maximum pulse repetition rate of the optical output signal of the generator. The state of the modulator of the pattern generator may be changed at a slow rate equal to or less than the repetition rate of the primary laser pulses. The change in the state of the modulator may be timed using an advance interval to reduce (amplitude) noise in the optical output signal.

[0017] The change in state of the modulator may be synchronized with the first light pulse, which may arrive at the modulator at the very end, near the falling edge of the control signal pulse, to maximize the time it takes for the modulator to settle to the target state.

[0018] As an example, the fundamental pulse rate (fundamental frequency f0) of the primary optical pulse may be, for example, 2 GHz, and the time interval (T0) between adjacent primary optical pulses of one branch may be 500 ps. The time width (w0) of the primary optical pulse may be, for example, 10 ps. The timing of the control pulse (S1) applied to the modulator (MOD1) is set to the time interval (T0) between the primary optical pulse (LB0 kThe generator may be selected to have no or little residual ringing remaining due to state changes when the first optical pulse (LB0 k ) may be operated to reach the modulator (MOD1) approximately 450 ps after the initiation of the previous state change of the control signal (S1) applied to the modulator (MOD1). C ) can be set to, for example, 450 ps.

[0019] The amplitude of a pulse of the optical output signal may be substantially independent of the preceding signal value.The optical output signal may be substantially free of memory effects.

[0020] The control unit may generate a low-noise electrical control signal. The control unit may, for example, comprise a driver unit that couples the electrical control input of the modulator to a first voltage (V1) and a different second voltage (V2). The first voltage (V1) and / or the second voltage (V2) may be output by a low-noise (DC) voltage source. The driver unit of the control unit may comprise a driver circuit that switches between two low-noise DC voltages (V1, V2).

[0021] The optical pulse sequence generating device can generate an optical output signal with high quality with respect to, for example, pulse amplitude and time noise (jitter).

[0022] The output of the optical pattern generating device may be converted to an electrical signal as needed, for example to obtain any electrical waveform. The converted electrical signal may have precise timing and / or precise waveform. The output of the optical pattern generating device may be converted to an electrical signal using, for example, a photodiode.

[0023] In one embodiment, one or more functional units of the optical pulse sequence generator may be mounted on a substrate. For example, a branch may be formed by mounting an optical waveguide, a modulator, and / or an optical delay line on the substrate. For example, a laser, a distributor, each branch, and / or a combiner may be mounted on the substrate. The substrate may be, for example, a silicon substrate or a GaAs substrate. GaAs stands for gallium arsenide. Mounting each unit on a substrate can achieve miniaturization, high frequency operation, improved pulse quality of the output signal, improved stability, improved reliability, and / or reduced manufacturing costs.

[0024] In one embodiment, the optical output of the generator can be connected from a high temperature to a cryogenic temperature via an optical waveguide. Cryogenic temperatures can be, for example, 4.2 K or lower, where K stands for Kelvin. Introducing an optical signal into a cryostat can avoid crosstalk and / or thermal effects compared to outputting an electrical signal into the cryostat. Optionally, the optical signal can be converted into an electrical signal within the cryostat. Pulses of the optical signal can be converted into an electrical signal using one or more photodiodes, if desired.

[0025] In one embodiment, the optical output of the generator may be used to drive, for example, a Josephson junction voltage standard.

[0026] In the following examples, some variants are explained in more detail with reference to the accompanying drawings. [Brief explanation of the drawings]

[0027] [Figure 1(a)] FIG. 1 illustrates an optical pattern generating device. [Figure 1(b)] FIG. 1 illustrates an optical pattern generating device. [Figure 1(c)] FIG. 1 illustrates an optical pattern generating device. [Figure 2(a)] FIG. 1 illustrates the formation of a primary light pulse from a primary laser pulse. [Figure 2(b)] FIG. 10 illustrates the formation of a modulated signal from a primary optical pulse. [Figure 2(c)] FIG. 10 illustrates combining modulated signals to form an output signal. [Figure 3] FIG. 1 illustrates converting an optical output signal to an electrical output signal. [Figure 4] FIG. 1 illustrates converting an optical output signal to an electrical output signal. [Figure 5(a)] FIG. 1 illustrates an optical pattern generating device that outputs several pulse patterns with different wavelengths. [Figure 5(b)] FIG. 1 illustrates an optical pattern generating device that outputs a first pulse pattern having a first polarization state and a second pulse pattern having a second orthogonal polarization state. [Figure 6(a)] FIG. 1 illustrates an optical pattern generating device that amplifies an uninterrupted stream of pulses of different wavelengths. [Figure 6(b)] FIG. 1 illustrates an optical pattern generating device that amplifies an uninterrupted stream of pulses with orthogonally different polarization states. [Figure 6(c)] FIG. 1 illustrates an uninterrupted stream of pulses composed of a first interrupted stream and a second interrupted stream. [Figure 7(a)] FIG. 1 illustrates the formation of a modulated signal from pulses using a Mach-Zehnder interferometer. [Figure 7(b)] FIG. 1 illustrates the formation of a modulated signal from pulses of two different wavelengths using a Mach-Zehnder interferometer. [Figure 7(c)] FIG. 1 illustrates the use of a Mach-Zehnder interferometer to form a first modulated signal and a complementary second signal. [Figure 8(a)] FIG. 1 illustrates an optical pattern generating device that outputs a pulse pattern consisting of pulses with two different polarization states. [Figure 8(b)] FIG. 1 illustrates an optical pattern generating device that outputs a pulse pattern consisting of pulses with two different polarization states. [Figure 9] FIG. 10 is a diagram illustrating a generated pulse pattern consisting of multi-level pulses. [Figure 10] FIG. 2 is a diagram illustrating a driving unit of the optical pattern generating device. [Figure 11] FIG. 1 illustrates an example of an optical pattern generating device that forms optical pulse patterns of multiple different wavelengths. DETAILED DESCRIPTION OF THE INVENTION

[0028] As shown in FIG. 1(a), the optical pattern generating device OPG1 includes a light source LS1 that outputs a primary optical pulse LB00, two or more branches (A1, A2, ...), a splitter SPL1 that splits the light of the primary optical pulse LB00 into each branch (A1, A2), a multiplexer CMB1 that combines the modulated signals of each branch (A1, A2), and a control unit PG0 that outputs control signals (S1, S2, ...) that form a modulated signal from the optical pulse (LB0).

[0029] The light source LS1 emits a beam of light for a predetermined time duration (w 00 The light source LS1 outputs a first-order light pulse LB00 having a constant repetition rate f0. The light source LS1 may irradiate the first-order light pulse LB00 at a constant repetition rate f0. The light source LS1 is, for example, a mode-locked laser. The light source LS1 may include a mode-locked laser. The light source LS1 may output laser pulses having, for example, a uniform amplitude and / or low (temporal) jitter.

[0030] The first light pulse LB00 may also be called, for example, a first laser pulse LB00.

[0031] The demultiplexer SPL1 may demultiplex the light of the primary laser pulse LB00 into branches (A1, A2, ...) to form a primary optical pulse (LB0). The demultiplexer SPL1 may comprise an optical input IN1 for inputting the primary optical pulse LB00. The multiplexer CMB1 may receive modulated signals LB1 from different branches A1, A2. The multiplexer CMB1 may combine the modulated signals LB1 of the different branches A1, A2 to form a combined optical output signal LB2. The multiplexer CMB1 may comprise an optical output OUT2 for outputting the output signal LB2.

[0032] The device OPG1 may include a plurality of optical branches A1, A2, A3, A4, ... The number of branches (m) may be in the range of 10 to 1000, for example. The number of branches (m) may be 4 or more, for example. The number of branches (m) may be in the range of 4 to 1024, for example.

[0033] The splitter SPL1 may receive the first laser pulses LB00 at a pulse repetition frequency f0. The output signal LB2 may have a maximum pulse repetition frequency M·f0, where the integer M indicates the number of splits in the device OPG1.

[0034] Each branch (A1, A2, ...) may comprise an optical modulator MOD for forming a modulated signal (LB1) from the first-order optical pulse (LB0). The modulator may include, for example, a controllable interferometer. The modulator MOD may be, for example, a Mach-Zehnder modulator. The modulator MOD may be, for example, an electrically controllable Mach-Zehnder modulator. The modulator MOD may have a first operating state that allows the first-order optical pulse to propagate through the modulator MOD and a second operating state that prevents the first-order optical pulse from propagating through the modulator MOD. The state of the modulator MOD can be set by applying a control signal S to the modulator MOD. The modulator may be set to the first state by applying a control signal pulse to the modulator MOD. The modulator MOD may form a modulated optical signal LB1 by modulating the first-order optical pulse LB0.

[0035] The device OPG1 comprises waveguides WG1 and WG2 that guide the primary optical pulse LB0 and / or the modulated optical signal LB1.

[0036] Each branch A1, A2 may produce a propagation delay d1, d2. Each branch A1, A2 may comprise a delay line D1, D2 for generating the propagation delay d1, d2. The device OPG1 may be operated such that the propagation delay d1 of the first branch A1 is different from the propagation delay d2 of the second branch A2. The propagation delay d3 of the third branch A3 may be different from the propagation delay d1 of the first branch A1 and different from the propagation delay d2 of the second branch A2. In particular, each branch may have a different propagation delay so that the pulse repetition rate of the output signal formed by combining the modulated signals of each branch is maximized. Each delay line may be operated such that the minimum difference between the propagation delays (d1, d2) of the first branch and the other branches is substantially equal to 1 / (M·f0). Each branch may have a different propagation delay to avoid combining superimposed pulses in the combiner.

[0037] The splitter SPL1 splits the primary laser pulse LB00 k By simultaneously branching the light into branches A1, A2, A3, and A4, the first optical pulse LB0 k,1 , LB0 k,2 , LB0 k,3 , LB0 k,4 The light pulse LB0 may be generated. k,1 , LB0 k,2 , LB0 k,3 , LB0 k,4 The shape of the laser pulse LB00 k The shape of each light pulse LB0 may be substantially the same as that of k,1 , LB0 k,2 , LB0 k,3 , LB0 k,4 The (maximum) optical power of the first laser pulse LB00 k The optical power may be 1 / M times the (maximum) optical power of the optical fiber 100, where M is the number of branches.

[0038] The first optical branch A1 of the device OPG1 may comprise a first modulator MOD1 and a delay line D1. The delay line D1 may be implemented, for example, by a waveguide (WG1). The delay line D1 may be located, for example, before or after the modulator. The modulator MOD1 of the first branch A1 modulates the optical pulse LB0 according to a control signal S1. k,1 to generate a first modulated optical signal LB1 k,1 may be output.

[0039] The second optical branch A2 of the device OPG1 may also comprise a second modulator MOD2 and a delay line D2. The modulator MOD1 of the second branch A2 modulates the optical pulse LB0 according to a control signal S2. k,2 to generate a second modulated optical signal LB1 k,2 may be output.

[0040] The device OPG1 may comprise a control unit PG0 which generates control signals S1, S2 for controlling the modulators MOD1, MOD2 of each branch A1, A2. The control unit PG0 may comprise multiple (parallel) outputs which output separate control signals S1, S2 for each modulator MOD1, MOD2. The timing of each control signal S1, S2 is determined by a synchronization signal S TRG1 and / or may be based on a timing signal obtained from a clock CLK1. The control unit PG0 may include, for example, a clock CLK1, a pattern memory MEM1, a data processing unit PROC1, and a driving unit DRV1.

[0041] The pattern memory MEM1 may store a primary pattern PAT0. The primary pattern PAT0 is made up of, for example, values ​​b1, b2, b3, b4, ... for defining the envelope function of the output signal LB2 of the device OPG1. The values ​​(b k,1 , b k,22(c) also shows an example of the control signals S1, S2, S3, and S4. The values ​​b1, b2, b3, and b4 may be binary values, for example. Each binary value may be 0 or 1. The data processing unit PROC1 may read the values ​​b1, b2, b3, and b4 from the pattern memory MEM1 and control the operation of the driving unit DRV1 based on the values ​​b1, b2, b3, and b4 of the primary pattern PAT0 to generate the control signals S1, S2, S3, and S4. Each control signal S1 may be, for example, an electrical signal having a first voltage value (V1) or a second voltage value (V2). Applying a first voltage value to the modulator MOD1 can place the modulator MOD1 in a first pass state, which allows an optical pulse to propagate through the modulator. Applying a second voltage value to the modulator MOD1 can place the modulator MOD1 in a second block state, which prevents an optical pulse from propagating through the modulator.

[0042] The data processor PROC1 can initiate a change of state of the modulator by sequentially outputting primary control signals (eg, values ​​b1, b2, b3, b4) to the driver DRV1.

[0043] The generation of the control signals S1, S2, S3, S4 may be synchronized with the laser pulse LB00. TRG1 The device OPG1 may output the optical synchronization signal S in synchronization with the operation of the light source LS1, as needed. TRG1 The electrical synchronization signal S TRG1 The oscilloscope may have a converter CON1 for converting

[0044] The waveguides WG1, WG2, WG3, and WG4 may be optical fibers, for example. The splitter SPL1, the modulators MOD1 and MOD2, and the multiplexer CMB1 may be separate optical components, for example.

[0045] The functional units (SPL1, WG1, MOD, D1, CMB1) of the device OPG1 may be mounted on a common substrate, for example, which may be a silicon or gallium arsenide substrate.

[0046] The light source LS1 may include an optical amplifier for increasing the power of the first light pulse LB00, if necessary. For example, the optical amplifier may amplify a laser pulse obtained from a seed pulse laser to output the first light pulse LB00.

[0047] The optical pattern generation device OPG1 can generate the optical pulse pattern OPAT1, for example, by the following method.

[0048] Divide the primary laser pulse (LB00) into multiple primary light pulses (LB0), Propagating a first-order light pulse (LB0) along different optical branches (A1, A2, A3, A4) of the device OPG1, Forming a modulated optical signal (LB1) by modulating an optical pulse (LB0) propagating through different optical branches (A1, A2, A3, A4); Different delay times (Δt D1 , Δt D2 , Δt D3 , Δt D4 ) to delay the modulated optical signal (LB1) or the optical pulse (LB0), · Delay modulated signals (LB1) from different optical branches (A1, A2, A3, A4) are multiplexed to form an optical signal (LB2).

[0049] The primary pulse (LB00) is, for example, a laser pulse obtained from a laser light source. The optical pattern generation device OPG1 includes, for example, a laser light source that generates a laser pulse.

[0050] The optical pattern generating device OPG1 may comprise one or more splitters SPL1 that split the primary laser pulse (LB00) into multiple primary light pulses (LB0).

[0051] The optical pattern generating device OPG1 may comprise an array MAR1 of one or more modulators MOD1, MOD2, MOD3, MOD4 that form a modulated optical signal (LB1) from the optical pulse (LB0) or the delayed optical pulse (LB0'). The modulators may be, for example, Mach-Zehnder modulators.

[0052] The optical pattern generator OPG1 generates different delay times (Δt D1 , Δt D2 , Δt D3 , Δt D4 ) each delay line may be implemented by a waveguide of a different length.

[0053] The optical pattern generator OPG1 may comprise one or more combiners CMB1 for combining the delayed modulated signals (LB1) from the different optical branches (A1, A2, A3, A4).

[0054] Each branch (A1, A2, A3, A4) may comprise an independently controllable modulator (MOD1, MOD2, MOD3, MOD4) and a delay line D1, D2, D3, D4.

[0055] The output OUT1 of the multiplexer CMB1 outputs an optical signal LB2 containing a desired arbitrary optical pulse pattern PAT1. The maximum pulse repetition rate of the optical pulse pattern PAT1 at the multiplexer output OUT1 is equal to M·f0, where f0 denotes the repetition rate of the primary pulse (LB00), and M denotes the number of branches (A1, A2, A3, A4) that output signals to the multiplexer CMB1. The number of branches M may be in the range of 4 to 1024, for example.

[0056] 1(b) and 1(c), the optical pattern generator OPG1 may include one or more optical amplifiers (AMP3) for amplifying the optical power of the optical pulses, as needed. For example, the optical amplifier AMP3 may optically amplify the pulse LB2 obtained from the output OUT1 of the multiplexer CMB1 to output an amplified output signal LB3. Note that "time" in the drawings means time or clock time.

[0057] Referring to Figure 1(b), the modulators (MOD1, MOD2, MOD3, MOD4) may modulate the primary optical pulse (LB0) to form a modulated primary signal (LB0'). The delay lines (D1, D2, D3, D4) may form a delayed modulated signal (LB1) from the modulated primary signal (LB0').

[0058] Referring to Figure 1(c), delay lines (D1, D2, D3, D4) may be located between the splitter SPL1 and the modulators (MOD1, MOD2, MOD3, MOD4). In this case, each modulator may form a modulated delayed signal (LB1) by modulating the delayed optical pulse (LB0).

[0059] In one embodiment, the timing of the first pulse (LB00) is adjusted, for example, by the synchronization signal S SYNC In one embodiment, the timing of the primary pulse (LB00) may be based on the frequency of the atomic clock (CLK1).

[0060] The state of each modulator may be set to a pass state or a block state. In the block state, the modulator can prevent the propagation of an optical pulse. In the pass state, the modulator can allow the propagation of an optical pulse. Thus, in the pass state, the modulator can output an optical pulse that is present. In the block state, the modulator can output an optical pulse that is missing.

[0061] The optical pattern generating device OPG1 may comprise a control unit PG0 for controlling the state of the modulator. The optical pattern generating device OPG1 may comprise a memory MEM1 for storing a primary pattern PAT0. The control unit PG0 controls the optical pattern generating device OPG1 in accordance with the primary pattern PAT0 and in accordance with the timing signal S SYNCThe optical pattern generating device OPG1 may include one or more data processing units PROC1 that output control signals b1, b2, b3, and b4 that change the states of the modulators in response to the control signals b1, b2, b3, and b4. The optical pattern generating device OPG1 may also include a driver unit DRV1 that amplifies the control signals b1, b2, b3, and b4 as needed. For example, the driver unit DRV1 may output high-voltage drive signals S1, S2, S3, and S4 for the modulators based on the control signals b1, b2, b3, and b4 as needed.

[0062] Each modulator may be modulated at a frequency equal to or less than the repetition rate of the primary optical pulse LB00.

[0063] The maximum modulation frequency of each modulator (MOD1, MOD2, MOD3, MOD4) may be equal to the repetition rate f0 of the primary pulse (LB00). The repetition rate f0 of the primary pulse (LB00) may be, for example, less than 10 GHz, or even less than 1 GHz. Even when generating an arbitrary waveform, it is not necessary to change the state of an individual modulator to a repetition rate higher than f0. Therefore, the maximum pulse repetition rate of the optical pulse pattern PAT1 can be higher than the maximum modulation rate of each individual modulator.

[0064] Figure 2(a) shows the primary laser pulse LB00 k The first light pulse LB0 k,1 , LB0 k,2 , LB0 k,3 , LB0 k,4 The splitter SPL1 is a diagram illustrating how the first laser pulse LB00 is formed. k The light is split into the first optical pulse LB0 k,1 , LB0 k,2 , LB0 k,3 , LB0 k,4 The symbol d may be formed. 00 indicates the propagation delay. Propagation delay d 00 may be, for example, the optical propagation delay from the input IN1 of the splitter SPL1 to the modulator MOD1. MAX is the time required for each light pulse LB0 k,1 , LB0 k,2 , LB0 k,3 , LB0 k,4The maximum power of the optical pulse LB0 of the first branch A1 can be expressed as k,1 is the time t k reaches the modulator MOD1 of the first branch A1.

[0065] code T 00 is a continuous laser pulse LB00 k , LB00 k+1 The time interval T 00 For example, laser pulse LB00 k , LB00 k+1 The symbol T0 can be defined by the rising edge of successive light pulses LB0 k,1 , LB0 (k+1),1 The time interval T0 is, for example, the time interval between the light pulses LB0 k,1 , LB0 (k+1),1 The time interval T0 can be defined by the rising edge of the time interval T 00 The pulse repetition frequency f0 of the light source LS1 may be equal to 1 / T 00 The pulse repetition frequency f0 of the light source LS1 may be, for example, in the range of 1 GHz to 10 GHz. The pulse repetition frequency f0 of the light source LS1 may be, for example, in the range of 2 GHz to 5 GHz.

[0066] sign w 00 Laser Pulse LB00 k , LB00 k+1 The symbol w0 represents the time width of the light pulse LB0 k,1 , LB0 (k+1),1 The width w0 represents the time width of the 00 The laser pulse LB00 may be approximately equal to k , LB00 k+1 The time width w0 can be set in the range of 1 ps to 100 ps, ​​for example.

[0067] FIG. 2(b) is a diagram illustrating the formation of a modulated signal LB1 from a primary optical pulse LB0 according to a primary pattern PAT0. The primary pattern PAT0 can be defined, for example, by a sequence of values. The primary pattern PAT0 can be defined, for example, by a sequence of values ​​bk,1 , b k,2 , b k,3 , b k,4 , b (k+1),1 , b (k+1),2 , b (k+1),3 , b (k+1),4 , b (k+2),1 , b (k+2),2 , b (k+2),3 , b (k+2),4 The primary pattern PAT0 may, for example, comprise a sequence of binary values. The value (b) of the primary pattern PAT0 may, for example, be stored in a memory MEM1 of the device OPG1.

[0068] The control unit PG0 is able to output control signals S1, S2, S3, S4 according to a primary pattern PAT0 which control the modulators of each branch A1, A2, A3, A4 of the device OPG1.

[0069] 1st light pulse LB0 k,1 is the time t k , the first branch A1 may reach the input of the modulator MOD1. k,1 The change in state of the modulator MOD1 may be initiated before the symbol d C is the time interval from the start of the state change to the arrival of the state. C is sometimes called the advance interval. Advance interval d C is, for example, the successive first-order light pulses LB0 of the first branch A1. k,1 , LB0 (k+1),1 The interval d may be in the range of 50% to 90% of the interval T0. C This can improve the stability of the modulated signal LB1 and / or make the maximum frequency of the control signal S1 equal to or less than the reference frequency f0.

[0070] The control signal S1 applied to the modulator MOD1 may include a control signal pulse. For example, the control signal pulse S1 k By forming the first light pulse LB0 k,1 The code w may be modulated. S is the control signal pulse S1k The time width of the control signal pulse S1 k Time span w S is, for example, the successive first-order light pulses LB0 of the first branch A1. k,1 , LB0 (k+1),1 The interval may be in the range of 50% to 90% of the interval T0.

[0071] 1st light pulse LB0 k,1 When passing through the modulator MOD1, the travel distance d is set to keep the modulator MOD1 in the passing state. C and / or time span w S You can select:

[0072] The modulator MOD1 of the first branch A1 outputs the first-order optical pulse LB0 k,1 , LB0 (k+1),1 , LB0 (k+2),1 , ... to form a first modulated signal LB1. The modulator MOD1 of the first branch A1 may be controlled based on a first subset of the primary pattern PAT0. The first subset may, for example, be a set of values ​​b k,1 , b (k+1),1 , b (k+2),1 The control unit PG0 may generate a control signal S1 according to the first subset. The control signal S1 is applied to the modulator MOD1 to modulate the optical pulse LB0 of the first branch A1. k,1 , LB0 (k+1),1 , LB0 (k+2),1 For example, the control value b k,1 The control signal S1(t) corresponding to k,1 In this case, the modulator MOD1 is set to the pass state, and the pulse LB0 k,1 Then, pulse LB0 k,1 may propagate to the combiner CMB1. For example, the control value b (k+1),1 The control signal S1(t) corresponding to (k+1),1 In this case, the modulator MOD1 is turned off, and the pulse LB0 (k+1),1 This allows the modulator MOD1 to prevent the propagation of pulse LB0 (k+1),1can be prevented from propagating to the multiplexer CMB1 via the branch A1.

[0073] The modulator MOD2 of the second branch A2 outputs the first-order optical pulse LB0 k,2 , LB0 (k+1),2 , LB0 (k+2),2 , ... to form a second modulated signal LB1. The modulator MOD2 of the second branch A2 may be controlled based on a second subset of the primary pattern PAT0. The second subset may, for example, be based on values ​​b k,2 , b (k+1),2 , b (k+2),2 The control unit PG0 may generate a control signal S2 according to the second subset. The control signal S2 is applied to the modulator MOD2 to modulate the optical pulse LB0 of the second branch A2. k,2 , LB0 (k+1),2 , LB0 (k+2),2 , ... may be allowed and / or prevented from propagating.

[0074] Similarly, the third subset of the primary pattern PAT0 may be, for example, the value b k,3 , b (k+1),3 , b (k+2),3 The third branch A3 may include the optical pulse LB0 k,3 , LB0 (k+1),3 , LB0 (k+2),3 , ... may be modulated according to a third subset of the primary pattern PATO.

[0075] Similarly, the fourth subset of the primary pattern PAT0 may be, for example, the value b k,4 , b (k+1),4 , b (k+2),4 The fourth branch A4 may include the optical pulse LB0 k.4 , LB0 (k+1),4 , LB0 (k+2),4 , ... may be modulated according to a fourth subset of the primary pattern PATO.

[0076] 2(c), the passed pulses propagate to the combiner, and the blocked pulses do not propagate to the combiner, which may combine the passed pulses to form an optical output.

[0077] Light pulse LB0 k,1 is the time t k,1 The light pulse LB0 may reach the modulator MOD1 at k,1 The modulated signal LB1 k,1 is the time t' k,1 The modulated optical signal LB1 may arrive at the multiplexer CMB1 with a slight delay. k,1 is the time t'' k,1 At time t'', the signal LB1 can contribute to the combined output signal LB2 with a slight delay. k,1 is the signal part LB2 at the output OUT2 of the multiplexer CMB1 k,1 Departure time t'' k , 2 is the signal portion LB2 at the output OUT2 of the multiplexer CMB1 k,2 Indicates the departure time of the signal unit LB2. k,1 , LB2 k,2 , LB2 k,3 , LB2 k,4 is the same primary laser pulse LB00 k Signal part LB2 k,1 , LB2 k,2 , LB2 k,3 , LB2 k,4 is the same primary laser pulse LB00 k It may be formed indirectly from

[0078] The modulated optical signal LB1 of the first branch A1 is k,1 , LB1 (k+1),1 , LB1 (k+2),1 The signal section LB1 may include: k,1 is the time t' k,1 The signal may reach the combiner at signal section LB1. (k+1),1 is the time t' (k+1),1 The signal may reach the combiner at signal section LB1. (k+2),1 is the time t' (k+2),1 The shaded area in FIG. 2(c) is the signal portion where the modulator MOD1 cuts off the pulse (LB1 (k+1),1 , LB1 (k+2),1 ), and this interruption is due to the value b of the first subset of the primary pattern PAT0. (k+1),1, b (k+2),1 Signal section LB1 k,1 is the value b of the first subset of the primary pattern PAT0 k,1 may include a pulse passed through the modulator MOD1 according to

[0079] sign d C is the advance interval for controlling the modulator of the first branch A1. P represents the propagation delay from the input of the combiner to the output of the combiner.

[0080] The propagation delay (d2) of the second branch A2 may be different from the propagation delay (d1) of the first branch A1, so that the first pulse LB1 passing through the modulator MOD1 of the first branch A1 k,1 and the second pulse LB1 passed through the modulator MOD2 of the second branch A2. k,2 and the same primary laser pulse LB00 k In the situation formed from the second pulse LB1 k,2 is the first pulse LB1 k,1 The beam reaches the combiner CMB1 slightly later than the beam

[0081] Output pulse (LB2 k,1 , LB2 k,2 , LB2 k,3 , LB2 k,4 ) are the same primary laser pulse LB00 k In the situation formed from the output pulse (LB2 k,1 , LB2 k,2 , LB2 k,3 , LB2 k,4 ) departure time (t'' k,1 , t'' k,2 , t'' k,3 , t'' k,4 ) may be selected to be approximately evenly distributed in time at the output OUT2 of the combiner CMB1.

[0082] The symbol T2 indicates the first pulse LB1 in the combiner. k,1and the rising edge of the second pulse LB1 at the combiner. k,2 This represents the minimum time interval between the rising edge of the output signal (LB2 k ) continuous pulse (LB2 k,1 , LB2 k,2 The minimum time interval (t2) between rising edges of the signals t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16, t17, t18, t19, t20, t21, t22, t23, t24, t25, t26, t27, t28, t29, t29, t28, t29, t29, t20, t21, t21, t22, t23, t24, t25, t26, t27, t28, t29, t29, t29, t20, t21, t22, t23,

[0083] 2(c) is a diagram illustrating an optical output signal LB2 obtained by multiplexing modulated optical signals LB1 from different branches A1, A2, A3, and A4. k is the first primary laser pulse LB00 k The signal sequence LB2 can be composed of modulated and delayed optical pulses derived from k+1 is the second primary laser pulse LB00 k+1 The optical output signal LB2 may comprise a light pulse pattern PAT1 formed according to the primary pattern PAT0.

[0084] The device OPG1 operates to prevent successive pulses of the output signal LB2 from overlapping, thereby preventing interference at the combiner. For example, the minimum time interval g3 between the falling edge of a first pulse and the rising edge of the next pulse may be, for example, 1 ps or more.

[0085] The symbol w2 represents the time width of the pulse of the output signal LB2. The width w2 of the output pulse is, for example, the width w of the primary laser pulse LB00. 00 is approximately equal to

[0086] In FIG. 3, the device OPG1 optionally converts the optical output LB2 into an electrical output V OUT The converter CON1 may include, for example, one or more photodiodes D1A, which may be connected in series with a resistor R1.

[0087] The symbol VCC may represent a bias voltage relative to the reference node N0. The symbol N1 may represent a common node between the photodiode D1A and the resistor R1. The node N1 may represent, for example, a voltage of the electrical output signal V relative to the reference node N0 and / or the bias voltage VCC. OUT can be output.

[0088] Referring to FIG. 4, the device OPG1 optionally includes a first set of branches A 1A , A 2A , A 3A , A 4A and the second set of branches A 1B , A 2B , A 3B , A 4B The first set of modulated signals may be multiplexed in a first multiplexer CMB1A. The first multiplexer CMB1A may output a first output signal LB2A from a first output OUT2A. The second set of modulated signals may be multiplexed in a second multiplexer CMB1B. The second multiplexer CMB1B may output a second output signal LB2B from a second output OUT2A. First laser pulse LB00 k may be split into a first set and a second set. This allows the second output signal LB2B to be accurately synchronized with the first output signal LB2A. The first optical output signal LB2A and the second optical output signal LB2B may be used to drive, for example, two photodiodes D1A and D1B.

[0089] The photodiodes D1A and D1B are connected in antiparallel, for example, and a high-frequency (M f0) AC voltage signal V OUT Output.

[0090] 5(a), an optical pattern generating device OPG1 may include a first light source LS1 that outputs first laser pulses at a first wavelength λ1 and a second light source LS2 that outputs second laser pulses at a different second wavelength λ2. The device OPG1 may include one or more splitters SPL1, a first modulator array MAR1, and a first delay array DAR1 that form a plurality of first modulated delayed signals LB1 from the first laser pulses at the first wavelength λ1. The device OPG1 may include one or more splitters SPL2, a second modulator array MAR2, and a second delay array DAR2 that form a plurality of second modulated delayed signals LB1 at a second wavelength λ2. The device OPG1 may include one or more multiplexers CMB1, CMB2, and CMB3 that combine the modulated delayed signals (LB1) to form a combined output signal (LB2). The optical amplifying device OPG1 may include an optical amplifier AMP3 that optically amplifies the combined signal (LB2) and outputs an amplified optical signal LB3.

[0091] The output signal (LB2) may comprise a first pulse pattern PAT1 consisting of pulses of a first wavelength λ1 and a second pulse pattern PAT2 consisting of pulses of a second wavelength λ2.

[0092] The device OPG1 may output a first pulse pattern PAT1 and a second pulse pattern PAT2 such that the arrival times of the pulses of the first pulse pattern PAT1 and the arrival times of the pulses of the second pulse pattern PAT2 are interlaced at the input of the optical amplifier AMP3. The propagation delays of the different branches of the device OPG1 may be selected such that the pulses of the first pulse pattern PAT1 and the pulses of the second pulse pattern PAT2 are interlaced. The device OPG1 may optionally include an optical delay element D for delaying the second pulse pattern PAT2 relative to the first pulse pattern PAT1 such that the arrival times of the pulses are interlaced. C2 may also be provided.

[0093] The device OPG1 provides an uninterrupted stream of optical pulses to the input of the optical amplifier AMP3, for example to stabilize the operation of the optical amplifier.

[0094] The first amplified pulse pattern PAT1 may optionally be separated from the amplified output signal by a spectrally separating component (FIG. 6(a)).

[0095] Referring to FIG. 5(b), the apparatus OPG1 may comprise a polarization rotation component ROT1 for changing the polarization states of the optical pulses.

[0096] The device OPG1 may include one or more splitters SPL1, a first modulator array MAR1, and a first delay array DAR1 that form a plurality of first modulated delayed signals LB1 from the laser pulses. The first modulated delayed signals LB1 may have a first polarization state POL1. The device OPG1 may include one or more splitters SPL2, a second modulator array MAR2, and a second delay array DAR2 that form a plurality of second modulated delayed signals LB1 at a second wavelength λ2. A second pulse pattern PAT2 may be formed by combining the second modulated delayed signals LB1. A polarization rotation component ROT1 may change the polarization state of the pulses in the second pattern PAT2 so that the pulses have a second polarization state (POL2) that is orthogonal to the first polarization state (POL1).

[0097] The first pulse pattern PAT1 and the second pulse pattern PAT2 may be combined to generate a combined signal LB3 consisting of pulses having a first polarization state (POL1) and pulses having a second polarization state (POL2). The pulses of the first pulse pattern PAT1 and the pulses of the second pulse pattern PAT2 may be interlaced.

[0098] Device OPG1 may provide an uninterrupted stream of optical pulses to the input of optical amplifier AMP3, for example to stabilize the operation of the optical amplifier.

[0099] The device (OPG1) amplifies an uninterrupted stream of pulses by an optical amplifier (AMP3), which may include pulses of different wavelengths (λ1, λ2) and / or pulses of different polarization states (POL1, POL2).

[0100] The device (OPG1) may combine pulses of different wavelengths (λ1, λ2) and / or pulses of different polarization states (POL1, POL2) to form an output signal (LB2, LB3) comprising pulses of different wavelengths (λ1, λ2) and / or pulses of different polarization states (POL1, POL2).

[0101] The first amplified pulse pattern PAT1 may optionally be separated from the amplified output signal by a polarization selective component (FIG. 6(b)).

[0102] The device OPG1 may include a demultiplexing section (DIC1) that is a wavelength selection section and / or a polarization selection section that selectively demultiplexes the pulse pattern (PAT1) from the output signals (LB2, LB3).

[0103] 6(a), a first amplified pulse pattern PAT1 may be optionally separated from the amplified output signal by a spectral separation component DIC1. The component DIC1 may have a first output OUT4A of the first pattern PAT1 at a first wavelength λ1. The component DIC1 may have a second output OUT4B of the second pattern PAT2 at a second wavelength λ2.

[0104] 6(b), a first amplified pulse pattern PAT1 may be optionally separated from the amplified output signal by a polarization selection component DIC1. The component DIC1 may have a first output OUT4A of the first pattern PAT1 with a first polarization state POL1. The component DIC1 may have a second output OUT4B of the second pattern PAT2 with a second polarization state POL2.

[0105] Referring to FIG. 6(c), apparatus OPG1 may provide an uninterrupted stream of optical pulses UNIPAT3 to the input of an optical amplifier, for example, to stabilize the operation of the optical amplifier. A stream of pulses may also be referred to, for example, as a sequence or pattern of pulses. The optical pulses of uninterrupted stream UNIPAT3 may have substantially equal energy. Uninterrupted stream UNIPAT3 may include a first optical pulse pattern OPAT1 at a first wavelength λ1 and a second optical pulse pattern OPAT2 at a second wavelength λ2. Uninterrupted stream UNIPAT3 may include the first optical pulse pattern OPAT1 consisting of pulses having a first polarization state (POL1) and the second optical pulse pattern OPAT2 consisting of pulses having a second, orthogonal polarization state (POL2).

[0106] The uninterrupted stream UNIPAT3 may include a first interrupted stream of light pulses (OPAT1) and a second interrupted stream of light pulses (OPAT1). The interrupted stream may have missing pulses, i.e., the time between some consecutive pulses may be significantly longer than the average time between consecutive pulses. The uninterrupted stream has no missing pulses. The time between consecutive pulses of the uninterrupted stream is substantially constant.

[0107] The uninterrupted stream UNIPAT3 may include three or more optical pulse patterns (λ1, λ2, λ3) of different wavelengths, in which at least two optical pulse patterns are interrupted.

[0108] The spectral separation between adjacent wavelengths λ1, λ2 may be, for example, greater than 0.1 nm.

[0109] In one embodiment, a first uninterrupted optical pulse train (UNIPAT1) having a first wavelength λ1 and a second uninterrupted optical pulse train (UNIPAT1) having a different second wavelength λ2 may propagate simultaneously along one branch (e.g., A1) of the device OPG1 to a modulator (MOD1). The modulator (MOD1) may be a Mach-Zehnder modulator that allows either pulses of the first wavelength λ1 or pulses of the second wavelength λ2 to pass through the modulator (MOD1) depending on the state of the modulator. This allows the modulator (MOD1) to form a third uninterrupted optical pulse train (UNIPAT1) from pulses of the first wavelength λ1 and pulses of the second wavelength λ2. The optical pulses of the third uninterrupted optical pulse train may be guided to an optical amplifier for amplification, if desired.

[0110] A first uninterrupted optical pulse series (UNIPAT1) having a first wavelength λ1 and a second uninterrupted optical pulse series (UNIPAT1) having a different second wavelength λ2 may be propagated simultaneously along each branch (A1, A2, A3, A4) of the device OPG1 to a modulator (MOD1), thereby obtaining an uninterrupted modulated optical pulse series (UNIPAT1) from each branch (A1, A2, A3, A4) of the device OPG1.

[0111] As shown in FIG. 7(a), a Mach-Zehnder modulator MZI (e.g., MOD1) has a first input IN1 for inputting an optical pulse of a first wavelength λ1. M and a first output OUT1 that outputs a modulated signal including pulses of a first wavelength λ1. M and

[0112] The Mach-Zehnder modulator MZI includes a first arm ARM1 and a second arm ARM2. At least one of the arms ARM1 and ARM2 may include a modulation element E1. By applying a control signal S1 to the modulation element E1, the state of the Mach-Zehnder modulator MZI can be changed from a pass state to a block state and / or from a block state to a pass state for pulses of a first wavelength λ1.

[0113] Referring to FIG. 7(b), the first input IN1M The Mach-Zehnder modulator MZI can receive a first pulse having a first wavelength λ1 and a second pulse having a second wavelength λ1. The Mach-Zehnder modulator MZI outputs either the first pulse or the second pulse to a first output OUT1. M The Mach-Zehnder modulator MZI may output an uninterrupted stream of pulses from the first pulse and the second pulse.

[0114] As shown in Fig. 7(c), the Mach-Zehnder modulator MZI has a first input IN1 to which a first pulse of a first wavelength λ1 is input and a second pulse of a second wavelength λ2 is input. Depending on the state of the Mach-Zehnder modulator MZI, the Mach-Zehnder modulator MZI outputs either the first pulse or the second pulse to a first output OUT1. M The Mach-Zehnder modulator MZI may output an uninterrupted stream of pulses from the first pulse and the second pulse.

[0115] The Mach-Zehnder modulator MZI outputs a second output OUT2 that outputs a complementary pulse pattern consisting of a first pulse and a second pulse. M The second output OUT2 may be provided. M is the first output OUT1 M The output signal may be a second output signal that is complementary to the first output signal output by the output signal generator.

[0116] The symbol COU1 can represent an optical coupler to the Mach-Zehnder modulator MZI. M may represent the second input of the Mach-Zehnder modulator MZI.

[0117] As shown in Figure 8(a), each modulator may receive pulses at a first wavelength λ1 and a second wavelength λ2, allowing each arm of device OPG1 to output an uninterrupted stream of pulses at wavelengths λ1 and λ2.

[0118] The device OPG1 may comprise a polarization rotation component ROT1 for changing the polarization state of the signal modulated by the second modulator array MAR2.

[0119] The device OPG1 may output an uninterrupted stream of interlaced pulses having different wavelengths λ1, λ2 and / or different polarization states (POL1, POL2) that are orthogonal to each other.

[0120] Each pulse may be amplified by an optical amplifier AMP3 if necessary.

[0121] The device OPG1 may include a demultiplexing unit DIC1 that demultiplexes the first pulse pattern PAT1 from the multiplexed optical signal. The demultiplexing unit DIC1 may be a wavelength selection unit or a polarization selection unit.

[0122] Referring to FIG. 8(d), the device OPG1 may optionally include a first optical amplifier (AMP31) that amplifies pulses having a first polarization state (POL1) and a second optical amplifier (AMP32) that amplifies pulses having a second polarization state (POL2).

[0123] Referring to FIG. 9, device OPG1 can output multi-level optical pulses. The modulators (MOD1, MOD2, MOD3, MOD4) may output levels other than a present pulse (logic level 1) and a missing pulse (logic level 0). For example, each modulator may have three or more states that output one or more intermediate signal levels in addition to a zero level (0) and a full level (1). For example, each modulator may output a half-level optical pulse (50%) in addition to a missing (blocked) pulse and a full level pulse (100%).

[0124] The optical pattern generator OPG1 can output optical signals LB2, LB3 including two or more optical pulse patterns PAT1, PAT2 at different wavelengths λ1, λ2. The optical pulse patterns PAT1, PAT2 may be interlaced to provide a substantially continuous envelope for the generated optical waveform.

[0125] By forming the optical signals LB2, LB3 from pulses of two or more different wavelengths l1, l2, it is possible to avoid interference effects when successive pulses overlap. The device OPG1 may be operated such that the wavelengths λ1, λ2 of the successive pulses of the output signal are different.

[0126] By forming the optical signals LB2, LB3 from pulses of different polarization states (POL1, POL2), interference effects can be avoided when successive pulses partially overlap. The device OPG1 may be operated such that successive pulses of the output signal have mutually different polarization states (POL1, POL2). The output signals LB2, LB3 may comprise a first pulse and a second pulse, the first pulse partially overlapping the second pulse, the first pulse having a first polarization state POL1 and the second pulse having a second polarization state POL2 that is orthogonal to the first polarization state.

[0127] The device (OPG1) forms output signals (LB2, LB3) comprising pulses of different wavelengths (λ1, λ2) and / or different polarization states (POL1, POL2), which may consist of successive pulses that partially overlap each other.

[0128] 10, the driver unit DRV1 of the generator OPG1 may, for example, include a plurality of voltage sources SUP11, SUP12, ..., SUP46 that output control voltages for the modulators MOD1, MOD2, MOD3, MOD4. The voltage sources SUP11, SUP12, ..., SUP46 may, for example, be low-noise voltage sources.

[0129] The control voltage output by the driver DRV1 may have two or more levels.

[0130] The driver unit DRV1 may include two or more voltage sources SUP11, SUP12 that output two different control voltage levels for each modulator to put the modulator into a pass state or a block state.

[0131] The driver DRV1 may include three or more voltage sources SUP11, SUP12 that output three or more control voltage levels to each modulator to form multi-level optical pulses.

[0132] The number of different voltage levels may be, for example, 3 or more. Figure 10 shows a driver DRV1 for outputting six voltage levels to four modulators.

[0133] Driver unit DRV1 may have a first array of switches SW11, SW12, ..., SW16 that connect a first output of driver unit DRV1 to one of voltage sources SUP11, SUP12, SUP13, SUP14, SUP15, SUP16. Switches SW11, SW12, SW13, SW14, SW15, SW16 may be connected to a first output via a first conductor WIR1 to output a first control voltage S1 for first modulator MOD1. The first control voltage S1 may be applied to a control input of first modulator MOD1 via conductor WIR1.

[0134] The switches SW11, SW12, SW13, SW14, SW15, and SW16 can galvanically connect one voltage source SUP11, SUP12, SUP13, SUP14, SUP15, or SUP16 to the first modulator (MOD1).

[0135] Driver unit DRV1 may include a second array of switches SW21, SW22, ..., SW26 that connect a second output of driver unit DRV1 to one of voltage sources SUP21, SUP22, ..., SUP26. Each switch may be connected to the second output via a second conductor WIR2 to provide a second control voltage S2 for the second modulator MOD2. A second control voltage S1 may be applied to a control input of the second modulator MOD2 via conductor WIR2.

[0136] The driver DRV1 may include a third array of switches SW31, SW32, ..., SW36 that connect a third output of the driver DRV1 to one of the voltage sources SUP31, SUP32, ..., SUP36. Each switch may be connected to the third output via a third conductor WIR3 to output a third control voltage S4 for the third modulator MOD3. The third control voltage S4 may be applied to a control input of the third modulator MOD3 via the conductor WIR3.

[0137] Driver unit DRV1 may include a fourth array of switches SW41, SW42, ..., SW46 that connect a fourth output of driver unit DRV1 to one of voltage sources SUP41, SUP42, ..., SUP46. Each switch may be connected to the fourth output via a fourth conductor WIR4 to output a fourth control voltage S4 for the fourth modulator MOD4. The fourth control voltage S4 may be applied to a control input of the fourth modulator MOD4 via the conductor WIR4.

[0138] Each switch can be implemented by, for example, a transistor. The driver DRV1 may include a switch control unit that controls the operations of the switches SW11, SW12, and SW46 in accordance with signals b1, b2, b3, and b4 that indicate the value of the primary pattern PAT0. The driver DRV1 may form control signals S1, S2, S3, and S4 for the modulators MOD1, MOD2, MOD3, and MOD4 in accordance with the signals b1, b2, b3, and b4, and the generated optical pulse pattern OPAT1 may correspond to the primary pattern PAT0.

[0139] By connecting the control voltage output by the switch to a voltage source, a stable control voltage for the modulator can be output.

[0140] In one embodiment, driver DRV1 may optionally include multiple dummy loads DUM1 that output a substantially constant load to each of voltage sources SUP11...SUP46. Switches SW11, SW12, and SW46 can connect voltage sources SUP11...SUP46 to either the dummy load 46 or modulators MOD1, MOD2, MOD3, and MOD4, respectively, to stabilize the operation of voltage sources SUP11...SUP46.

[0141] In one embodiment, the voltage sources SUP11...SUP46 may be adjustable and / or controllable. The generator OPG1 may optionally include a controller V_CNT1 that controls the voltage levels of the voltage sources SUP11...SUP46 based on a feedback signal indicative of the pulse energy of the modulated pulses to stabilize the operation of the modulator. The driver DRV1 may also include a controller V_CNT1 that controls the voltage levels of the voltage sources SUP11...SUP46.

[0142] Referring to FIG. 11, the generator OPG1 may include one or more optical amplifiers AMP1, AMP2, AMP31, and AMP32 that optically amplify optical pulses. The optical amplifiers AMP1, AMP2, AMP31, and AMP32 are, for example, semiconductor optical amplifiers and / or fiber amplifiers. Examples of the fiber amplifiers include erbium-doped fiber amplifiers and ytterbium-doped fiber amplifiers. The one or more optical amplifiers AMP1 may be arranged, for example, between the splitter SPL1 and the modulators (MAR1 and MAR2), between the modulators (MAR1 and MAR2) and the delay lines (DAR1 and DAR2), between the delay lines (DAR1 and DAR2) and the multiplexer CMB1, and / or after the multiplexer CMB1. The amplification of the one or more optical amplifiers may be adjustable.

[0143] The generator OPG1 may include one or more detectors MON1 for monitoring the pulse energy of the optical pulses. For example, a detector MON1 may monitor the pulse energy of the optical pulses propagating through each branch of the generator OPG1. The detector MON1 may output a feedback signal indicative of the detected pulse energy. The generator OPG1 may control the operation of a driver, a modulator, and / or an amplifier based on the feedback signal obtained from the detector MON1 to stabilize the operation of the generator OPG1.

[0144] In one embodiment, each branch of the generator OPG1 may include an optical pulse energy sensor (MON1), an intensity modulator, and an optical amplifier. By separating the pulse energy sensor (MON1) and the intensity modulator by a distance that provides a sufficient time delay for the feedback signal from the sensor and controlling the transmittance of the modulator in the same branch as the optical amplifier, fluctuations in pulse energy can be effectively reduced or eliminated. Fluctuations in pulse energy can be caused, for example, by changing the time interval between pulses.

[0145] In one aspect, the transmittance of an intensity modulator in the same branch as the optical amplifier may be adjusted based on the known response of the amplifier to the optical pulse pattern. The transmittance of the intensity modulator may be controlled in advance (predictively) based on the known shape of the optical pulse pattern and the known response of the amplifier to the optical pulse pattern.

[0146] The generator OPG1 may include one or more diffractive splitters SPL1 and one or more diffractive multiplexers that generate a plurality of optical pulse patterns of different wavelengths λ1, λ2, ..., λ8. The generator OPG1 may also include a spectrally selective splitter unit DIC1 that separates one or more pulse patterns from the optical signal of the generator OPG1, as needed.

[0147] To suppress or avoid interference between overlapping optical pulses, the spectral spacing between adjacent different wavelengths λ 1 , λ 2 , . . . , λ 8 may be, for example, greater than 0.1 nm.

[0148] The generator OPG1 may optionally include a temperature control system to maintain one or more functional parts of the generator at a constant operating temperature.

[0149] In an embodiment, the optical output of the generator may be used to drive a Josephson junction voltage standard. The Josephson junction voltage standard may be located within a cryostat. The optical output may be connected to the cryostat using, for example, an optical fiber. The optical output may be converted into a high-frequency electrical waveform inside the cryostat using, for example, one or more photodiodes. The operating temperature of the Josephson junction voltage standard may be, for example, 4.2 K or less. Coupling the optical output to the cryostat has little effect on the operating temperature of the Josephson junction voltage standard. A voltage calibration device may include the generator and the Josephson junction voltage standard.

[0150] In one embodiment, the device may be operated such that the smallest difference between the propagation delays (e.g., d2 - d1) of the first branch and the other branches is substantially less than 1 / (M·f0). This small difference can, for example, cause a (small) change in the pulse repetition frequency of the optical output. This small difference can result in micro-stepping the temporal position of the optical pulses of the output.

[0151] In one embodiment, the primary laser pulses may have a broad spectral linewidth. The demultiplexer may be a spectral splitter and / or the combiner may be a spectral combiner. The optical pulses propagating in the different branches may have different wavelengths.

[0152] In one embodiment, the optical output from the multiplexer may be amplified using an optical amplifier. The apparatus OPG1 may comprise an optical amplifier. The optical output may be connected to the optical amplifier.

[0153] In one embodiment, the light output from the multiplexer may be converted into supercontinuum light. The device OPG1 may include a conversion unit that converts the light output from the multiplexer into supercontinuum light.

[0154] In one embodiment, the first laser pulse LB00 may be a supercontinuum laser pulse. The light source LS1 may be, for example, a supercontinuum light source.

[0155] In one embodiment, the generator OPG1 comprises: forming a first uninterrupted optical pulse train including pulses of different wavelengths; forming a second uninterrupted optical pulse train comprising pulses of different wavelengths; Rotating the polarization of the second uninterrupted optical pulse sequence; - combining the first interruption-free optical pulse sequence and the polarization-rotated second interruption-free optical pulse sequence to form a combined interruption-free optical pulse sequence; The first optical output signal may be formed by splitting the combined uninterrupted optical pulse sequence.

[0156] The uninterrupted sequence can be formed, for example, using a Mach-Zehnder modulator.

[0157] The optical pulses of the uninterrupted series may optionally be amplified at one or more locations. The first uninterrupted optical pulse series may be optically amplified before combining. The second uninterrupted amplified optical pulse series may be optically amplified before combining. The combined uninterrupted optical pulse series may be optically amplified after combining.

[0158] The generator OPG1 may convert the first optical output signal into a first electrical signal.

[0159] In one embodiment, the generator OPG1 comprises: forming a first uninterrupted amplified optical pulse series including pulses of different wavelengths; The first uninterrupted amplified optical pulse sequence may be split to form a first optical output signal. The uninterrupted sequence can be formed, for example, using a Mach-Zehnder modulator.

[0160] The generator OPG1 may convert the first optical output signal into a first electrical signal.

[0161] In one embodiment, the generator OPG1 comprises: forming a first uninterrupted optical pulse train including pulses of different wavelengths; forming a second uninterrupted optical pulse train comprising pulses of different wavelengths; combining the first and second uninterrupted optical pulse sequences to form a combined uninterrupted optical pulse sequence; The first optical output signal may be formed by splitting the combined uninterrupted optical pulse sequence. The first and second uninterrupted sequences may be formed using, for example, a Mach-Zehnder modulator.

[0162] The wavelength of the second uninterrupted optical pulse sequence may be different from the wavelength of the first uninterrupted optical pulse sequence. To reduce or avoid interference between overlapping optical pulses, the wavelength of the second uninterrupted optical pulse sequence may be different from the wavelength of the first uninterrupted optical pulse sequence. For example, the combined uninterrupted optical pulse sequence may include pulses of four or more different wavelengths.

[0163] The optical pulses may optionally be amplified at one or more locations. The first uninterrupted optical pulse series may be optically amplified before combining. The second uninterrupted optical pulse series may be optically amplified before combining. The combined uninterrupted optical pulse series may be optically amplified after combining.

[0164] The generator OPG1 may convert the first optical output signal into a first electrical signal.

[0165] In one embodiment, the generator OPG1 comprises: forming a first uninterrupted optical pulse train including pulses of different wavelengths; dispersing the first uninterrupted series of optical pulses to form a first optical output signal; converting the first optical output signal into a first electrical signal; forming a second uninterrupted optical pulse train comprising pulses of different wavelengths; dispersing the second uninterrupted series of optical pulses to form a second optical output signal; converting the second optical output signal into a second electrical signal; The first electrical signal and the second electrical signal may be combined to form a combined electrical signal.

[0166] The first and second uninterrupted sequences may be formed using, for example, a Mach-Zehnder modulator.

[0167] It will be apparent to those skilled in the art that modifications and variations of the systems, products, apparatus and methods according to the present invention may be used. The figures are schematic. With reference to the accompanying drawings, the specific embodiments described above are for illustrative purposes only and do not limit the scope of the present invention as defined by the appended claims.

Claims

1. An optical pattern generator (OPG1), comprising: ・Primary laser pulse (LB00 ｋ a light source (LS1) that outputs The primary laser pulse (LB00 ｋ ) into multiple branches (A1, A2, A3) to generate multiple first-order optical pulses (LB0 ｋ，１ , LB0 ｋ，２ , LB0 ｋ，３ a splitter (SPL1) that outputs A modulated optical signal (LB1) from each of the branches (A1, A2, A3) ｋ，１ , LB1 ｋ，２ , LB1 ｋ，３ ) are combined to produce an output signal (LB2 ｋ one or more combiners (CMB1) forming a a control unit (PG0) that outputs control signals (S1, S2, S3) for controlling the optical modulators (MOD1, MOD2, MOD3) of the branches (A1, A2, A3) according to a primary pattern (PAT0); The first branch (A1) derives a first modulated optical signal (LB1) from the primary optical pulse (LB0k,1) of the first branch (A1). ｋ，１ a first optical modulator (MOD1) forming a The second branch (A2) receives the first-order optical pulse (LB0 ｋ，２ ) to the second modulated optical signal (LB1 ｋ，２ a second optical modulator (MOD2) forming a The third branch (A3) receives the first-order optical pulse (LB0 ｋ，３ ) to the third modulated optical signal (LB1 ｋ，３ a third optical modulator (MOD3) forming a The propagation delay (d ２ ) is the propagation delay (d １ ) Unlike The propagation delay (d ３ ) is the propagation delay (d １ ) and the propagation delay (d ２ ) Unlike The device (OPG1) is arranged to form an uninterrupted stream (UNIPAT3) of return-to-zero (RZ) optical pulses, the uninterrupted stream (UNIPAT3) being of different wavelengths (λ １ , λ ２ ) and / or pulses of different polarization states (POL1, POL2), the pulses of said uninterrupted stream (UNIPATT3) have substantially equal energy; the time between successive pulses of said uninterrupted stream is substantially constant; The device (OPG1) is configured to form the uninterrupted stream (UNIPAT3) from a first uninterrupted stream of light pulses (PAT1) and a second uninterrupted stream of light pulses (PAT2).

2. 2. The device (OPG1) according to claim 1, further comprising an optical amplifier (AMP3) for optically amplifying said uninterrupted stream (UNIPAT1).

3. The light source (LS1) emits light of a first wavelength (λ １ ) and the primary laser pulse (LB00 ｋ ), and the device (OPG1) outputs a different second wavelength (λ ２ ) and the second laser pulse (LB00 ｋ 3. The device (OPG1) according to claim 1 or 2, further comprising a second light source (LS2) outputting a second light source (LS3).

4. Pulses of different wavelengths (λ １ , λ ２ ) and / or pulses (POL1, POL2) of different polarization states are multiplexed to generate pulses of different wavelengths (λ １ , λ ２ 4. The device (OPG1) according to claim 1, wherein the device (OPG1) generates an output signal (LB2, LB3) comprising pulses of different polarization states (POL1, POL2) and / or pulses of different polarization states (POL1, POL2).

5. The device (OPG1) described in any one of claims 1 to 4 further comprises a demultiplexing unit (DIC1) which is a wavelength selection unit and / or a polarization selection unit that selectively demultiplexes a pulse pattern (PAT1) from the output signal (LB2, LB3).

6. forming a first uninterrupted amplified optical pulse train comprising pulses of different wavelengths; - separating the first uninterrupted amplified series of optical pulses to form a first optical output signal; The device according to any one of claims 1 to 5.

7. forming a first uninterrupted series of optical pulses comprising pulses of different wavelengths; forming a second uninterrupted series of optical pulses comprising pulses of different wavelengths; - combining the first uninterrupted optical pulse sequence and the second uninterrupted optical pulse sequence to form a combined uninterrupted optical pulse sequence; - separating the combined uninterrupted optical pulse sequence to form a first optical output signal; The device according to any one of claims 1 to 6.

8. forming a first uninterrupted series of optical pulses comprising pulses of different wavelengths; forming a second uninterrupted series of optical pulses comprising pulses of different wavelengths; changing the polarization state of the second uninterrupted optical pulse sequence to an orthogonal state with respect to the first uninterrupted optical pulse sequence; - forming a combined uninterrupted optical pulse sequence by combining the first uninterrupted optical pulse sequence and the polarization-rotated second uninterrupted optical pulse sequence; - separating the combined uninterrupted optical pulse sequence to form a first optical output signal; The device according to any one of claims 1 to 7.

9. Apparatus according to any one of claims 6 to 8, adapted to convert the first optical output signal into a first electrical signal.

10. forming a first uninterrupted series of optical pulses; - dispersing said first uninterrupted series of optical pulses to form a first optical output signal; forming a second uninterrupted series of optical pulses; - separating the first uninterrupted series of optical pulses to form a second optical output signal; - combining the first optical output signal and the second optical output signal to form a combined optical output signal; An apparatus according to any one of claims 1 to 9.

11. 11. The apparatus of claim 10, wherein the combined optical output signal is converted into an electrical signal.

12. forming a first uninterrupted series of amplified optical pulses; - separating the first uninterrupted amplified optical pulse series to form a first optical output signal; converting the first optical output signal into a first electrical signal; forming a second uninterrupted series of amplified optical pulses; - separating the second uninterrupted amplified optical pulse series to form a second optical output signal; converting the second optical output signal into a second electrical signal; - combining the first electrical signal and the second electrical signal to form a combined electrical signal; The device according to any one of claims 1 to 5.

13. 13. The apparatus according to any one of claims 1 to 12, further comprising a cryostat, in which the optical output signal is converted into an electrical signal.

14. ・Primary laser pulse (LB00 ｋ ) and The primary laser pulse (LB00 ｋ ) into multiple branches (A1, A2, A3) to generate multiple first-order optical pulses (LB0 ｋ，１ , LB0 ｋ，２ , LB0 ｋ，３ ) and A modulated optical signal (LB1) from each of the branches (A1, A2, A3) ｋ，１ , LB1 ｋ，２ , LB1 ｋ，３ ) are combined to produce an output signal (LB2 ｋ ) and outputting control signals (S1, S2, S3) for controlling the optical modulators (MOD1, MOD2, MOD3) of said branches (A1, A2, A3) according to a primary pattern (PAT0), The first branch (A1) receives the first-order optical pulse (LB0 ｋ，１ ) to the first modulated optical signal (LB1 ｋ，１ a first optical modulator (MOD1) forming a The second branch (A2) receives the first-order optical pulse (LB0 ｋ，２ ) to the second modulated optical signal (LB1 ｋ，２ a second optical modulator (MOD2) forming a The third branch (A3) receives the first-order optical pulse (LB0 ｋ，３ ) to the third modulated optical signal (LB1 ｋ，３ a third optical modulator (MOD3) forming a The propagation delay (d ２ ) is the propagation delay (d １ ) Unlike The propagation delay (d ３ ) is the propagation delay (d １ ) and the propagation delay (d ２ ) Unlike The output signal (LB2 ｋ ) comprises an uninterrupted stream (UNIPAT3) of return-to-zero (RZ) optical pulses, said uninterrupted stream (UNIPAT3) being at different wavelengths (λ １ , λ ２ ) and / or pulses of different polarization states (POL1, POL2), the pulses of said uninterrupted stream (UNIPATT3) have substantially equal energy; the time between successive pulses of said uninterrupted stream (UNIPATT3) is substantially constant; A method, wherein said uninterrupted stream (UNIPAT3) is formed from a first intermittent train of optical pulses (PAT1) and a second intermittent train of optical pulses (PAT2).

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