Integrated photoelectric oscillator

Abstract

The invention discloses an integrated photoelectric oscillator, and relates to the technical field of microwave photons. The optical link comprises an optical link and an electrical link. And the optical link comprises a dual-mode laser, an optical coupler, an optical delay line integrated chip and a photoelectric detector, and integration of the optical link is realized by adopting a photon lead bonding technology. The dual-mode laser serves as a direct modulation light source and a microwave photon filter of the system. In the system, two optical delay lines with different lengths form a double-ring structure to suppress a loop mode. And the photoelectric detector converts a dual-mode optical signal into an electric signal, the electric signal is injected into the electrical loop, is amplified by the amplifier, is shunted by the power divider, and is fed back and modulated on the dual-mode laser, so that a closed loop is formed, and a microwave signal is output. According to the integrated photoelectric oscillator system, the system size and weight of the photoelectric oscillator can be remarkably reduced.

Description

Technical Field

[0001] The invention relates to the field of microwave photon technology, and in particular to an integrated photoelectric oscillator. Background Art

[0002] High-quality microwave signals have important applications in communications, radar systems, and sensing. The optoelectronic oscillator (OEO) system in microwave photonic technology has attracted widespread attention because it can generate microwave signals with low phase noise and high spectral purity. The classic optoelectronic oscillator system is composed of lasers, modulators, long optical fibers, detectors, RF amplifiers, and microwave bandpass filters. The oscillation frequency of the system is determined by the microwave bandpass filter. By using long optical fibers as low-loss energy storage media, the system Q value is effectively improved, and the optoelectronic oscillator can generate high-frequency, low-phase noise, and frequency-tunable high-quality microwave signals.

[0003] Due to the low loss characteristics of optical fiber, OEO systems usually use optical fibers that are several kilometers or even more than ten kilometers long. However, the problem caused by long optical fibers is that the spacing of the optoelectronic oscillation loop mode becomes smaller (the loop mode spacing corresponding to an optical fiber with a length of 10 km is 20kHz), and a very narrow bandwidth (~kHz) filter is required to achieve single-mode oscillation. However, it is still unrealistic to achieve such a narrow bandwidth electrical filter in the high-frequency microwave band. In addition, due to the influence of discrete optoelectronic devices and long optical fibers, the optoelectronic oscillator system is relatively large, which is not conducive to the widespread application of optoelectronic oscillators. Summary of the invention

[0004] In view of the problem of miniaturization of optoelectronic oscillator system, the present invention provides an integrated optoelectronic oscillator system. It adopts a multifunctional integrated chip and a hybrid integration method to realize an integrated optoelectronic oscillator. The integrated optoelectronic oscillator system adopts a dual-loop structure, which is beneficial to suppress the loop mode and improve the quality of the output microwave signal. This solution significantly reduces the volume of the optoelectronic oscillator system, and the integration method is simple and easy to implement.

[0005] The technical solution adopted by the present invention is specifically as follows:

[0006] An integrated optoelectronic oscillator includes an optical link and an electrical link;

[0007] The optical link comprises:

[0008] Dual-mode semiconductor laser: used to generate modulated continuous dual-mode optical signals;

[0009] Coupler I: used to split the dual-mode optical signal into two beams;

[0010] Waveguide delay line: used for delay processing of received dual-mode optical signals;

[0011] Coupler II: used to combine delayed dual-mode optical signals;

[0012] Photoelectric detector: used to beat the combined dual-mode optical signal to obtain a microwave signal;

[0013] The electrical link includes:

[0014] Bias tee I: used to input microwave signal into electrical link;

[0015] Electric amplifier: used to amplify the power of microwave signals;

[0016] Electric coupler: used to split the microwave signal into two paths, obtaining two microwave signals with half the power, one of which is used for feedback loop and the other for output;

[0017] Bias II: used to input a part of the microwave signal separated by the coupler into the modulated dual-mode laser to form a closed optoelectronic oscillation loop;

[0018] The dual-mode laser generates a continuous dual-mode optical signal, which enters coupler I. Coupler I divides the dual-mode optical signal into two paths. The two dual-mode optical signals enter an optical delay line waveguide respectively, and the two dual-mode optical signals are delayed respectively; the delayed dual-mode optical signal enters coupler II, and coupler II combines the two delayed dual-mode optical signals; the combined dual-mode optical signal enters the photodetector to beat the frequency, and a microwave signal is obtained; the microwave signal output by the optical link is input into the electrical link through bias device I, and the microwave signal input into the electrical link is power amplified by the electrical amplifier. The amplified microwave signal is divided into two paths by the electrical coupler, and two microwave signals with half the power are obtained. One microwave signal is fed back to the dual-mode laser of the optical link through bias device II to form a closed photoelectric oscillation loop, and the other is used for output.

[0019] Furthermore, the dual-mode laser is a III-V indium phosphide-based monolithic integrated semiconductor laser.

[0020] Furthermore, the dual-mode laser is used as a direct-modulation light source and microwave photon filter of the optoelectronic oscillator system, the beat frequency signal of the dual-mode optical signal is used as an oscillation seed source of the system, and the mode spacing (Δf) of the dual-mode optical signal determines the oscillation frequency (f osc ).

[0021] f osc =Δf=|f1-f2|

[0022] Among them, f1-f2 are the frequencies corresponding to the two modes respectively.

[0023] Furthermore, the coupler I, optical delay line and coupler II are all integrated into a chip based on silicon nitride low-loss material, with a specific structure as follows: a 1x2 port combiner I splits and connects two waveguide delay lines of different lengths, which are then combined by a 1x2 port coupler II.

[0024] Furthermore, two waveguide delay lines with different lengths constitute two optoelectronic closed loops with different lengths, thereby suppressing the loop mode.

[0025] Furthermore, the dual-mode laser, the coupler and the waveguide delay line integrated chip, and the photodetector are integrated by photon wire bonding.

[0026] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0027] (1) The present invention realizes an integrated optoelectronic oscillator system by adopting a multifunctional integrated chip and a hybrid integration solution, thereby reducing the volume and weight of the optoelectronic oscillator system.

[0028] (2) The present invention uses a dual-path optical delay line chip as the energy storage medium of the system, which is beneficial to reducing the volume of the system. The two optical waveguide delay lines of the dual-path optical delay line chip have different lengths and different loop mode spacings, which is beneficial to suppressing the loop mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the structure of an integrated optoelectronic oscillator according to an embodiment of the present invention. DETAILED DESCRIPTION

[0030] Below, the present invention is further described in conjunction with the accompanying drawings.

[0031] To facilitate understanding of the present application, the technical solution of the present disclosure will be described in more detail below in conjunction with the accompanying drawings. However, it should be understood that this embodiment is only used to fully describe the present disclosure and is not all embodiments of the present disclosure.

[0032] This embodiment proposes an integrated optoelectronic oscillator. The integrated optoelectronic oscillator is realized by adopting a multifunctional integrated chip and a hybrid integration solution. The integrated optoelectronic oscillator includes an optical link and an electrical link. The structural diagram is shown in FIG. Figure 1 As shown, the optical link includes:

[0033] Dual-mode laser: used to generate modulated continuous dual-mode optical signals;

[0034] Coupler I: used to split the dual-mode optical signal into two beams;

[0035] Waveguide delay line: used for delaying the dual-mode optical signal;

[0036] Coupler II: used for combining the delayed dual-mode optical signals;

[0037] Photoelectric detector: used to beat the combined dual-mode optical signal to obtain a microwave signal;

[0038] The electrical link includes:

[0039] Bias device I: used to input the microwave signal output by the detector into the electrical link;

[0040] Electric amplifier: used to amplify the power of microwave signals output by the detector;

[0041] Electric coupler: used to split the microwave signal into two paths, so as to obtain two microwave signals with half the power, one of which is used for feedback loop and the other for output;

[0042] Bias device II: It is used to input a part of the microwave signal separated by the coupler into the modulated dual-mode laser to form a closed optoelectronic oscillation loop.

[0043] The dual-mode laser generates a continuous dual-mode optical signal, which enters coupler I. Coupler I divides the dual-mode optical signal into two paths. The two dual-mode optical signals enter an optical delay line waveguide respectively, and the two dual-mode optical signals are delayed separately. The delayed dual-mode optical signal enters coupler II, and coupler II combines the two delayed dual-mode optical signals. The combined dual-mode optical signal enters the photodetector to beat the frequency and obtain a microwave signal. The microwave signal output by the optical link is input into the electrical link through bias device 1. The microwave signal input into the electrical link is power amplified by the electrical amplifier. The amplified microwave signal is divided into two paths by the electrical coupler to obtain two microwave signals with half the power. One microwave signal is fed back to the dual-mode laser of the optical link through bias device II to form a closed photoelectric oscillation loop, and the other is used for output.

[0044] Preferably, the dual-mode laser, coupler I, waveguide delay line and coupler II integrated chip, and the photodetector are integrated by photon wire bonding.

[0045] Preferably, the dual-mode semiconductor laser may be a III-V indium phosphide-based monolithic integrated semiconductor laser, and the dual-mode semiconductor laser outputs a dual-mode optical signal when driven by a direct current signal.

[0046] In the embodiment, the dual-mode semiconductor laser serves as the direct-modulation light source and microwave photon filter of the optoelectronic oscillator system, and the beat frequency signal of the dual-mode optical signal serves as the oscillation seed source of the system, determining the oscillation frequency of the optoelectronic oscillator system.

[0047] In the embodiment, a dual-loop structure is adopted, the length of the optical delay line waveguide of each loop is different, and the mode spacings corresponding to the two loops are different, which is conducive to suppressing side mode signals.

[0048] In the embodiment, the coupler I, the optical delay line and the coupler II are integrated chips based on low-loss materials such as silicon nitride, and the specific structure is that the 1x2 port coupler I splits and connects two waveguide delay lines of different lengths, and then the 1x2 port coupler II combines the beams;

[0049] Preferably, the electrical link is integrated on a printed circuit board.

[0050] An integrated optoelectronic oscillator is realized by adopting a multifunctional integrated chip and a hybrid integrated solution, and the integrated optoelectronic oscillator includes an optical link and an electrical link. The optical link includes a dual-mode laser, an optical coupler, an optical delay line integrated chip, and a photodetector, and the integration of the optical link is realized by using photon wire bonding technology. The dual-mode laser serves as a direct-modulated light source and a microwave photon filter of the system. Two optical delay lines of different lengths in the system form a dual-loop structure to suppress the loop mode. The electrical link of the integrated optoelectronic oscillator includes a bias device, an electrical amplifier, an electrical coupler, and a power divider, and the electrical devices are integrated on a printed circuit board. The dual-wavelength optical signal output by the dual-mode laser is divided into two paths through an optical coupler I, and then enters two delay lines respectively and then beam-combined into a photodetector. The photodetector converts the dual-mode optical signal into an electrical signal, which is injected into the electrical loop. After being amplified by the amplifier, the power divider divides the path and then feedback-modulated on the dual-mode laser to form a closed loop, and outputs a microwave signal. The integrated optoelectronic oscillator system of the present invention can significantly reduce the system volume and weight of the optoelectronic oscillator.

[0051] The above-described embodiments illustrate the preferred embodiments of the present invention, and the above-described embodiments are used to understand the method and core concept of the present application, but are not used to limit the present invention. Without departing from the principles of the present invention, modifications or substitutions made to the present invention by ordinary technicians in the field are deemed to be within the scope of protection of the present invention.

Claims

1. An integrated optoelectronic oscillator, comprising an optical link and an electrical link; characterized in that: The optical link comprises: Dual-mode semiconductor laser: used to generate modulated continuous dual-mode optical signals; Coupler I: used to split the dual-mode optical signal into two beams; Waveguide delay line: used for delay processing of received dual-mode optical signals; Coupler II: used to combine delayed dual-mode optical signals; Photoelectric detector: used to beat the combined dual-mode optical signal to obtain a microwave signal; The electrical link includes: Bias tee I: used to input microwave signals into the electrical link; Electric amplifier: used to amplify the power of microwave signals; Electric coupler: used to split the microwave signal into two paths, obtaining two microwave signals with half the power, one of which is used for feedback loop and the other for output; Bias II: used to input a part of the microwave signal separated by the coupler into the modulated dual-mode laser to form a closed optoelectronic oscillation loop; The dual-mode laser generates a continuous dual-mode optical signal, which enters coupler I. Coupler I divides the dual-mode optical signal into two paths. The two dual-mode optical signals enter an optical delay line waveguide respectively, and the two dual-mode optical signals are delayed respectively; the delayed dual-mode optical signal enters coupler II, and coupler II combines the two delayed dual-mode optical signals; the combined dual-mode optical signal enters the photodetector to beat the frequency, and a microwave signal is obtained; the microwave signal output by the optical link is input into the electrical link through bias device I, and the microwave signal input into the electrical link is power amplified by the electrical amplifier. The amplified microwave signal is divided into two paths by the electrical coupler, and two microwave signals with half the power are obtained. One microwave signal is fed back to the dual-mode laser of the optical link through bias device II to form a closed photoelectric oscillation loop, and the other is used for output.

2. An integrated optoelectronic oscillator according to claim 1, characterized in that: The dual-mode laser is a III-V indium phosphide-based monolithic integrated semiconductor laser.

3. The integrated optoelectronic oscillator according to claim 1, characterized in that: The dual-mode laser is used as a direct-modulation light source and microwave photon filter of the optoelectronic oscillator system, the beat frequency signal of the dual-mode optical signal is used as the oscillation seed source of the system, and the mode spacing Δf of the dual-mode optical signal determines the oscillation frequency f of the optoelectronic oscillator system. osc ; f osc =Δf=|f1-f2| Among them, f1-f2 are the frequencies corresponding to the two modes respectively.

4. The integrated optoelectronic oscillator according to claim 1, characterized in that: The coupler I, optical delay line and coupler II are all integrated in a chip based on silicon nitride low-loss material. The specific structure is as follows: the 1x2 port combiner I splits and connects two waveguide delay lines of different lengths, and then the 1x2 port coupler II combines the beams.

5. The integrated optoelectronic oscillator according to claim 4, characterized in that: Two waveguide delay lines with different lengths form two optoelectronic closed loops with different lengths, suppressing the loop mode.

6. The integrated optoelectronic oscillator according to claim 4, characterized in that: Among them, dual-mode lasers, couplers, waveguide delay line integrated chips, and photodetectors are integrated by photonic wire bonding.

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