阅读说明：本技术 一种基于硅基集成磁光环行器的光学全双工收发组件 (Optical full-duplex transmitting and receiving assembly based on silicon-based integrated magneto-optical circulator ) 是由 毕磊 严巍 刘书缘 秦俊 张燕 邓龙江 于 2020-05-08 设计创作，主要内容包括：本发明属于集成光学领域,具体涉及一种基于硅基集成磁光环行器的光学全双工收发组件。本发明中的硅基集成磁光环行器件结构采用硅基集成的马赫-曾德尔干涉结构或硅基集成的微环结构,结合互易与非互易移相对收发信号的相位进行调控,达到分离收发信号的目的。最终本发明大大降低了整体组件的尺寸及制备成本,改善了整体组件对回波信号的耦合性能；有效规避了在分立光学探测组件中存在的装调误差和低信噪比等问题,并提供了硅基集成磁光环行器、激光器、光探测器和激光天线一起集成的更优的技术方案,可以显著提高激光雷达等激光主动探测系统的性能,对降低系统的体积、重量、成本,具有重要意义。(The invention belongs to the field of integrated optics, and particularly relates to an optical full-duplex transceiving component based on a silicon-based integrated magneto-optical circulator. The silicon-based integrated magneto-optical ring device structure adopts a silicon-based integrated Mach-Zehnder interference structure or a silicon-based integrated micro-ring structure, and combines the reciprocal and non-reciprocal movement to regulate and control the phase of transmitting and receiving signals, thereby achieving the purpose of separating the transmitting and receiving signals. Finally, the size and the preparation cost of the whole assembly are greatly reduced, and the coupling performance of the whole assembly to echo signals is improved; the problems of installation and adjustment errors, low signal-to-noise ratio and the like existing in a discrete optical detection assembly are effectively avoided, a better technical scheme that a silicon-based integrated magneto-optical circulator, a laser, a light detector and a laser antenna are integrated together is provided, the performance of laser active detection systems such as a laser radar and the like can be remarkably improved, and the method has important significance for reducing the size, the weight and the cost of the system.)

1. An optics full duplex receiving and dispatching subassembly based on silica-based integrated magneto-optical circulator which characterized in that: the device consists of a laser, a light detector, a laser antenna and a silicon-based integrated magneto-optical circulator;

the silicon-based integrated magneto-optical circulator comprises a silicon-based integrated Mach-Zehnder interference structure or a silicon-based integrated micro-ring structure and a silicon-based integrated magneto-optical waveguide;

the input ports of the laser and the silicon-based integrated magneto-optical circulator are aligned and coupled with the input ports of the laser and the silicon-based integrated magneto-optical circulator through optical fibers, gratings or end faces, and are connected with the input ports of the silicon-based integrated magneto-optical circulator;

the optical detector and the receiving port of the silicon-based integrated magneto-optical circulator are aligned and coupled with the optical detector through an optical fiber, a grating or an end face, and are connected with the receiving port of the silicon-based integrated magneto-optical circulator;

the laser antenna and the transmitting port of the silicon-based integrated magneto-optical circulator are aligned and coupled with the transmitting port of the silicon-based integrated magneto-optical circulator through an optical fiber, a grating or an end face, and the transmitting port of the silicon-based integrated magneto-optical circulator is connected with the transmitting port of the silicon-based integrated magneto-optical circulator; the laser antenna collimates the laser generated by the laser and transmitted by the silicon-based integrated magneto-optical circulator, compresses the divergence angle of the received laser and transmits the laser; simultaneously receiving reflected light of the detected object;

when the silicon-based integrated magneto-optical circulator works, an input port of the silicon-based integrated magneto-optical circulator receives a detection signal generated by a laser and enters a laser antenna through the silicon-based integrated magneto-optical circulator to be transmitted in a single path, the detection signal processed by the laser antenna is reflected by an object to be detected to generate an echo signal, the echo signal is simultaneously received by the laser antenna and returns to the silicon-based integrated magneto-optical circulator through a transmitting port, and then returns to an optical detector externally connected with a receiving port from the other path, so that the purpose of duplexing is achieved.

2. The optical full-duplex transceiver module based on the silicon-based integrated magneto-optical circulator of claim 1, wherein:

the silicon-based integrated magneto-optical circulator adopts a silicon-based integrated Mach-Zehnder interference structure, and two interference arms of the structure perform steering processing on transmission by means of 180-degree bent waveguides, so that the steered waveguides are transmitted in opposite directions; the silicon-based integrated magneto-optical waveguide is respectively designed in the positive and negative transmission directions of the two arms of the silicon-based integrated Mach-Zehnder interference structure, so that the transmission of the light wave in the silicon-based integrated magneto-optical waveguide of one arm is positive, and the transmission in the other arm is reverse; the reciprocity phase difference of two arms of the silicon-based integrated Mach-Zehnder interference structure is odd times of pi/2; the nonreciprocal phase difference of the two arms of the silicon-based integrated Mach-Zehnder interference structure is pi/2 by designing the length of the silicon-based integrated magneto-optical waveguide;

the light splitting and light combining parts of the silicon-based integrated Mach-Zehnder interference structure are respectively composed of two integrated 3dB couplers; in four ports of a silicon-based integrated Mach-Zehnder interference structure, two ports on the same end face are respectively used as an input port of a silicon-based integrated magneto-optical circulator and a receiving port of the silicon-based integrated magneto-optical circulator; and in the other end face, a port isolated from the input port transmission of the silicon-based integrated magneto-optical circulator is hung, and the rest port is used as an emission port of the silicon-based integrated magneto-optical circulator.

3. The optical full-duplex transceiver module based on the silicon-based integrated magneto-optical circulator of claim 1, wherein:

the silicon-based integrated magneto-optical circulator adopts a silicon-based integrated micro-ring structure, the silicon-based integrated micro-ring structure comprises two parallel silicon-based integrated straight waveguides and a silicon-based integrated annular optical waveguide positioned between the two parallel silicon-based integrated straight waveguides, and the silicon-based integrated annular optical waveguide is circular or in a runway shape; the silicon-based integrated magneto-optical waveguide is arranged at the silicon-based integrated annular waveguide part;

in the four ports of the silicon-based integrated micro-ring structure, two ports on the same end surface are respectively used as an input port of the silicon-based integrated magneto-optical circulator and an emission port of the silicon-based integrated magneto-optical circulator; in the other end face, a port which is positioned in the same silicon-based integrated straight waveguide with the transmitting port of the silicon-based integrated magneto-optical circulator is used as a receiving port of the silicon-based integrated magneto-optical circulator, and the rest port is hung up and is not used.

4. The optical full-duplex transceiver module based on the silicon-based integrated magneto-optical circulator of claim 1, wherein: the laser, the optical detector, the laser antenna and the silicon-based integrated magneto-optical circulator are simultaneously integrated on a single chip on the same material substrate to form a completely integrated and interconnected optical detection component.

5. The optical full-duplex transceiver module based on the silicon-based integrated magneto-optical circulator of claim 1, wherein: the laser antenna is a phased array laser antenna to achieve spatial scanning.

Technical Field

The invention belongs to the field of integrated optics, and particularly relates to a laser active detection assembly based on a silicon-based photoelectronic technology.

Background

The silicon-based photoelectronic technology is developed rapidly in recent years, and due to the characteristics of excellent performance and compatibility with fine process characteristics, the silicon-based photoelectronic technology is gradually paid attention to in the fields of laser radar and laser active detection.

In a separate lidar system, the transmitting end and the receiving end typically employ two separate optical windows for lasing and detection. Two significant problems exist with such systems. First, the laser emission path and the laser detection path need to be precisely manually adjusted so that the optical axis of the emitted beam is coaxial or parallel with the optical axis of the receiving telescope. If errors occur in the adjustment, the signal intensity of the system is obviously influenced, and even the situation that the reflected echo cannot be detected occurs. Secondly, the laser detection light path usually has a large spatial detection angle range, so that strong ambient light enters the optical detector, which causes a low signal-to-noise ratio of the system in a strong light environment, and is difficult to realize remote detection.

The magneto-optical circulator can enable the laser detection emitting end and the laser receiving end to share the same antenna aperture, and the principle is that the optical nonreciprocal property of magneto-optical materials is utilized to enable reflected light to return to the optical detector along a light path different from that of the emitted light, so that the problems of installation and adjustment, low signal-to-noise ratio and the like are avoided. However, discrete optical circulators are large in size, costly, and difficult to couple with optical components such as lasers and detectors.

Disclosure of Invention

Aiming at the problems or the defects, in order to develop a miniaturized transmitting-receiving integrated optical detection component and avoid detection errors caused by the problems of manual adjustment, low signal-to-noise ratio and the like, the invention provides a silicon-based integrated magneto-optical circulator-based optical full-duplex transmitting-receiving component, which realizes full-duplex laser detection by the effective coupling of a laser, an optical detector, a laser antenna and a silicon-based integrated magneto-optical circulator and the characteristic of non-reciprocal transmission of a silicon-based integrated magneto-optical circulator.

The optical full-duplex transceiver component based on the silicon-based integrated magneto-optical circulator consists of a laser, an optical detector, a laser antenna and the silicon-based integrated magneto-optical circulator, wherein the silicon-based integrated magneto-optical circulator is a core device of the full-duplex laser detection component.

The silicon-based integrated magneto-optical circulator comprises a silicon-based integrated Mach-Zehnder interference structure or a silicon-based integrated micro-ring structure and a silicon-based integrated magneto-optical waveguide.

Further, for a silicon-based integrated mach-zehnder interference structure: the two interference arms of the structure divert the transmission by means of 180 ° bent waveguides so that the diverted waveguides are transmitted in opposite directions. The silicon-based integrated magneto-optical waveguide is respectively designed in the forward and reverse transmission directions of the two arms of the silicon-based integrated Mach-Zehnder interference structure, so that the transmission of the light wave in the silicon-based integrated magneto-optical waveguide of one arm is forward, and the transmission in the other arm is reverse. The reciprocity phase difference of two arms of the silicon-based integrated Mach-Zehnder interference structure is odd times of pi/2; and the nonreciprocal phase difference of the two arms of the structure is pi/2 by designing the length of the silicon-based integrated magneto-optical waveguide.

The light splitting and light combining parts of the silicon-based integrated Mach-Zehnder interference structure are respectively composed of two integrated 3dB couplers. In four ports of a silicon-based integrated Mach-Zehnder interference structure, two ports on the same end face are respectively used as an input port and a receiving port of a silicon-based integrated magneto-optical circulator; and in the other end face, a port isolated from the input port transmission is hung, and the rest port is used as an emission port of the silicon-based integrated magneto-optical circulator.

Further, for silicon-based integrated micro-ring structures: the structure comprises two silicon-based integrated straight waveguides which are parallel to each other and a silicon-based integrated annular optical waveguide which is positioned between the two silicon-based integrated straight waveguides which are parallel to each other, wherein the silicon-based integrated annular optical waveguide is circular or in a track shape. The silicon-based integrated magneto-optical waveguide is arranged on the silicon-based integrated annular waveguide part.

In the four ports of the silicon-based integrated micro-ring structure, two ports on the same end surface are respectively used as an input port of the silicon-based integrated magneto-optical circulator and an emission port of the silicon-based integrated magneto-optical circulator; in the other end face, a port which is positioned in the same silicon-based integrated straight waveguide with the transmitting port of the silicon-based integrated magneto-optical circulator is used as a receiving port of the silicon-based integrated magneto-optical circulator, and the rest port is hung up and is not used.

The input ports of the laser and the silicon-based integrated magneto-optical circulator are aligned and coupled with the input ports of the laser and the silicon-based integrated magneto-optical circulator through optical fibers, gratings or end faces, and are connected with the input ports of the silicon-based integrated magneto-optical circulator; the output power and the output wavelength of the laser depend on the specific application environment, and a discrete laser or a waveguide integrated laser can be selected and used.

The optical detector and the receiving port of the silicon-based integrated magneto-optical circulator are aligned and coupled with the optical detector through an optical fiber, a grating or an end face, and are connected with the receiving port of the silicon-based integrated magneto-optical circulator; the detection range and detection intensity of the optical detector depend on the laser source and the application environment, and a discrete optical detector or a waveguide integrated optical detector can be selected.

The laser antenna and the transmitting port of the silicon-based integrated magneto-optical circulator are aligned and coupled with the transmitting port of the silicon-based integrated magneto-optical circulator through an optical fiber, a grating or an end face, and the transmitting port of the silicon-based integrated magneto-optical circulator is connected with the transmitting port of the silicon-based integrated magneto-optical circulator; the laser antenna collimates the laser generated by the laser and transmitted to the laser through the silicon-based integrated magneto-optical circulator, and compresses the divergence angle of the laser to obtain better directivity and transmit the laser; and needs to receive weak reflected light of the detected object. The laser antenna may be formed by an integrated optical waveguide, an array of optical waveguides or a grating.

When the optical full-duplex transceiving component based on the silicon-based integrated magneto-optical circulator works, an input port of the silicon-based integrated magneto-optical circulator receives a detection signal generated by a laser and enters a laser antenna through the silicon-based integrated magneto-optical circulator to carry out single-path transmission, the detection signal processed by the laser antenna is reflected by an object to be detected to generate an echo signal, the echo signal is received by the laser antenna and returns to the silicon-based integrated magneto-optical circulator through a transmission port of the silicon-based integrated magneto-optical circulator, and then returns to an optical detector connected with a receiving port of the silicon-based integrated magneto-optical circulator from the other path, so that the duplex purpose is achieved.

Further, in order to improve the transmission efficiency of the entire assembly, further coupling optimization can be performed on each connection port, and it is also necessary to further improve the merit value of the magneto-optical waveguide, increase the radius of the curved waveguide, and the like, so that the loss of the entire assembly is minimized. If the coupling loss is completely eliminated, the laser, the optical detector, the laser antenna and the silicon-based integrated magneto-optical circulator need to be simultaneously and monolithically integrated on the same material substrate to form a completely integrated interconnected optical detection component. In addition, in order to obtain a larger detection range, a phased array laser antenna can be used as the laser antenna for the purpose of spatial scanning.

The silicon-based integrated magneto-optical circulator structure adopts a silicon-based integrated Mach-Zehnder interference structure or a silicon-based integrated micro-ring structure, and combines the reciprocal and non-reciprocal movement to regulate and control the phase of transmitting and receiving signals, thereby achieving the purpose of separating the transmitting and receiving signals. The optical full-duplex transceiving architecture based on the silicon-based integrated magneto-optical circulator greatly reduces the size and the preparation cost of the whole assembly, and improves the coupling performance of the whole assembly to echo signals; the problems of installation and adjustment errors, low signal-to-noise ratio and the like existing in a discrete optical detection assembly are effectively avoided, a better technical scheme that a silicon-based integrated magneto-optical circulator, a laser, a light detector and a laser antenna are integrated together is provided, the performance of laser active detection systems such as a laser radar and the like can be remarkably improved, and the method has important significance for reducing the size, the weight and the cost of the system.

Drawings

FIG. 1 is a schematic overall structure diagram of an embodiment of the present invention;

fig. 2 is a schematic cross-sectional view of a magneto-optical waveguide in the silicon-based integrated magneto-optical circulator according to the embodiment of the invention;

fig. 3 is a schematic diagram of the component in the y-direction of the electric field in the section TM zeroth order mode of the magneto-optical waveguide in the silicon-based integrated magneto-optical circulator according to the embodiment of the present invention;

fig. 4 is a schematic diagram of transmission lines of the probe signal and the echo signal according to an embodiment of the present invention.

Reference numerals: the optical fiber laser comprises a 1-laser, a 2-optical detector, a 3-laser antenna, a 4-silicon-based integrated magneto-optical circulator, a 5-silicon-based integrated magneto-optical waveguide, a 6-3dB coupler, a 7-silicon-based optical waveguide and an 8-silicon dioxide substrate.

Detailed Description

As described in the background section, in a discrete laser detection device, two independent optical windows are usually used for laser emission and detection at the emitting end and the receiving end, and such a system has problems of setup error and low signal-to-noise ratio. Meanwhile, the integral discrete component has large size and high cost and is difficult to couple with optical elements such as a laser, a detector, a transmitting antenna and the like.

The optical full-duplex transceiving component based on the silicon-based integrated magneto-optical circulator can obviously improve the detection performance and reduce the volume, the weight and the cost of the system.

The technical scheme adopted by the invention for solving the technical problems is as follows: a silicon-based integrated magneto-optical circulator is introduced into a traditional optical transceiving component, and a laser, a light detector and a laser antenna are coupled with the silicon-based integrated magneto-optical circulator respectively, so that a novel transceiving integrated laser detection component based on the silicon-based integrated magneto-optical circulator is formed. The silicon-based integrated magneto-optical circuit device adopted in the structure is prepared by photoetching and processing a silicon-based integrated optical waveguide structure and depositing magneto-optical materials.

The invention is further illustrated below with reference to examples and figures.

An optical full-duplex transceiving component based on a silicon-based integrated magneto-optical circulator is disclosed, wherein the preparation method of the silicon-based integrated magneto-optical circulator comprises the following steps:

step 1, photoetching and etching a semiconductor (including but not limited to silicon and silicon nitride materials) substrate to obtain a single-mode integrated optical waveguide and a Mach-Zehnder interference structure or a micro-ring structure, and carrying out phase control on output and received signals by combining reciprocal and non-reciprocal phase shifting.

And 2, growing a low-refractive-index cladding layer by sputtering and other methods to clad the whole device. And acts as a barrier layer for the deposition of magneto-optical materials including, but not limited to, silicon oxide materials.

And 3, obtaining a window for depositing the magneto-optical material at the upper surface of the designed magneto-optical waveguide through secondary photoetching, wherein the width of the window is larger than that of the optical waveguide. Under an external strong magnetic field horizontally perpendicular to the magneto-optical waveguide, the magneto-optical material can cause a TM polarization mode in the waveguide to generate nonreciprocal phase shift. In a silicon-based integrated Mach-Zehnder interference structure, the length of the magneto-optical waveguide should be such that the difference between the nonreciprocal phases of the forward and reverse transmitted light is pi/2.

And 4, growing (including but not limited to a pulse laser deposition technology and a wafer bonding technology) magneto-optical material (including but not limited to cerium-doped yttrium iron garnet) at the window.

And 5, designing a reciprocal and non-reciprocal phase shifting relation, so that the forward output signal and the reverse receiving signal are coupled into different waveguides, and realizing the separation of the transmitting and receiving signals.

The device structure of the embodiment is shown in figure 1, and comprises a 1-laser, a 2-photodetector, a 3-laser antenna, a 4-silicon-based integrated magneto-optical circulator, a 5-silicon-based integrated magneto-optical waveguide, a 6-3dB coupler, a 7-silicon-based optical waveguide and an 8-silicon dioxide substrate. The silicon-based integrated magneto-optical circulator is based on a Mach-Zehnder interference structure, the laser and the optical detector are respectively coupled with an input port and a receiving port of the silicon-based integrated magneto-optical circulator, and the laser antenna is coupled with an emitting port of the silicon-based integrated magneto-optical circulator (including but not limited to end face coupling and grating coupling technologies).

And a signal emitted from the laser enters the laser antenna through the silicon-based integrated magneto-optical circulator to be emitted. The laser antenna transmits the received laser (detection signal) with the compressed divergence angle, the detection signal is reflected by the object to be detected to generate an echo signal, the echo signal is received by the laser antenna and returns to the transmitting port of the silicon-based integrated magneto-optical circulator so as to be coupled into the silicon-based integrated magneto-optical circulator again, and the echo signal is transmitted to the receiving port along a path different from a transmitting optical path and enters the optical detector. The silicon-based integrated magneto-optical circulator realizes the separation of front and rear transmission signals by utilizing the optical nonreciprocal property of magneto-optical materials.

Fig. 2 shows a cross-sectional structure diagram of a magneto-optical waveguide in a silicon-based integrated magneto-optical circulator, in which a waveguide core layer is made of a semiconductor material (including, but not limited to, silicon and silicon nitride materials). In this embodiment: as a silicon waveguide, the thickness is 220nm and the width is 500 nm; the silicon nitride waveguide had a thickness of 400nm and a width of 1000 nm. The outside is made of silicon oxide (SiO)₂) As a low-index cladding, the thicknesses of Yttrium Iron Garnet (YIG) and cerium-doped yttrium iron garnet (Ce: YIG) of the upper cladding were 50nm and 100nm, respectively.

In silicon-based integrated optical waveguides, the propagation of light is confined to one transmission mode, the fundamental mode of the TM-mode₀Mode(s). The electric field distribution pattern of this mode is shown in fig. 3 and mainly appears as a component in the y direction.

Fig. 4 shows a transmission spectrum diagram of a probe signal and an echo signal of the optical full-duplex transceiving module based on the silicon-based integrated magneto-optical circulator of the present embodiment. During testing, an external magnetic field is applied in the horizontal direction perpendicular to the magneto-optical waveguide in the silicon-based integrated magneto-optical circulator, so that the magneto-optical film reaches magnetic saturation in the in-plane direction. The laser signal at the input port is a continuous spectrum with the wavelength from 1510nm to 1620nm, the optical power is set to 8dBm, and the laser signal is input into the silicon-based integrated magneto-optical circulator through an optical fiber by an end face coupling method. At the transmit port, the light waves are re-coupled into another fiber back into the photodetector to simulate the signal entering the laser antenna. The detection data is the wavelength and the corresponding light intensity, and the wavelength detection interval is set to be 2 pm.

The same laser and the same optical detector are used for respectively testing two paths of signals from the transmitting port to the input port and from the transmitting port to the receiving port so as to simulate the situation when the assembly receives echo signals. The transmission line can be seen near 1565nm wave band, the end face coupling loss is removed, compared with the transmission intensity of the silicon-based integrated straight waveguide, the signal transmission from the input port to the transmitting port is basically consistent with the signal transmission from the transmitting port to the receiving port, and the insertion loss of the silicon-based integrated magneto-optical circulator is about 4 dB. While the signal strength returning from the transmit port to the input port is additionally suppressed by 20 dB.

So far, the embodiment of the invention simulates and tests the optical transceiving component based on the silicon-based integrated magneto-optical circulator, and achieves crosstalk isolation between transceiving signals of 20dB and insertion loss of 4dB, thereby realizing the optical full-duplex transceiving component with better performance.