阅读说明：本技术 基于片上集成波导与半导体纳米线的复合结构单纵模激光器 (Composite structure single longitudinal mode laser based on-chip integrated waveguide and semiconductor nanowire ) 是由 童利民 鲍庆洋 郭欣 李维嘉 许培臻 于 2019-11-15 设计创作，主要内容包括：本发明公开了一种基于片上集成波导与半导体纳米线的复合结构单纵模激光器。包括半导体纳米线和片上集成波导,弯曲波导的两端依次连接耦合波导、输出光栅、输出光纤,两个耦合波导和半导体纳米线紧贴布置,形成马赫-曾德尔干涉结构形式的单纵模激光器；自由空间光入射到复合结构单纵模激光器上将半导体纳米线泵浦至激光阈值以上,经过半导体纳米线和弯曲波导组成的两干涉臂向两侧输出光信号,最后经输出光栅垂直输出到输出光纤。本发明具有低功耗、小型化、方向输出比率可调节、性能稳定、制备简便、结构简单、易于集成等特点,能实现两端输出比率10％至90％的光强调节。(The invention discloses a composite structure single longitudinal mode laser based on an on-chip integrated waveguide and a semiconductor nanowire. The optical fiber coupling device comprises a semiconductor nanowire and an on-chip integrated waveguide, wherein two ends of the curved waveguide are sequentially connected with a coupling waveguide, an output grating and an output optical fiber, and the two coupling waveguides and the semiconductor nanowire are arranged in a close fit manner to form a single longitudinal mode laser in a Mach-Zehnder interference structure form; free space light is incident on the single longitudinal mode laser with the composite structure to pump the semiconductor nanowire to be above a laser threshold value, light signals are output to two sides through two interference arms formed by the semiconductor nanowire and the bent waveguide, and finally the light signals are vertically output to an output optical fiber through an output grating. The invention has the characteristics of low power consumption, miniaturization, adjustable directional output ratio, stable performance, simple and convenient preparation, simple structure, easy integration and the like, and can realize the light intensity adjustment of the output ratio of 10 to 90 percent at two ends.)

1. A composite structure single longitudinal mode laser based on-chip integrated waveguide and semiconductor nanowire is characterized in that: the optical waveguide comprises a semiconductor nanowire (7) and an on-chip integrated waveguide, wherein the on-chip integrated waveguide comprises two optical output structures, two coupling waveguides (3), an oxide layer (4), a substrate layer (5) and a bent waveguide (6); the coupling waveguide (3), the bending waveguide (6) and the semiconductor nanowire (7) are arranged on an oxidation layer (4) together, a substrate layer (5) is arranged below the oxidation layer (4), the coupling waveguide (3) is connected to two ends of the bending waveguide (6), each coupling waveguide (3) is connected with an optical output structure, each optical output structure comprises an output grating (1) and an output optical fiber (2) which are sequentially connected from the end part of the coupling waveguide (3), and the two coupling waveguides (3) and the semiconductor nanowire (7) are arranged in a close fit manner to form a single longitudinal mode laser in a Mach-Zehnder interference structure form; free space light is incident on the single longitudinal mode laser with the composite structure to pump the semiconductor nanowire (7) to be above a laser threshold value, light signals are output to two sides through two interference arms formed by the semiconductor nanowire (7) and the bent waveguide (6), and finally the light signals are vertically output to the output optical fiber (2) through the output grating (1).

2. The single longitudinal mode laser with a composite structure based on the on-chip integrated waveguide and the semiconductor nanowire as claimed in claim 1, wherein: the coupling waveguide (3) is mainly composed of a straight line section positioned in the middle and arc sections arranged at two ends of the straight line section, the straight line section and the semiconductor nanowire (7) are arranged in a clinging mode, and the bending direction of the coupling waveguide (3) is opposite to that of the bending waveguide (6).

3. The single longitudinal mode laser with a composite structure based on the on-chip integrated waveguide and the semiconductor nanowire as claimed in claim 1, wherein: the output light intensity at the output optical fiber (2) is adjusted by adjusting the coupling waveguides (3) with different straight-line section lengths, and the proportion distribution of the output light intensity at the two output optical fibers (2) is adjusted by designing different lengths and length proportions of the straight-line sections of the coupling waveguides (3) at the two ends of the integrated waveguide on the chip.

4. The single longitudinal mode laser with a composite structure based on the on-chip integrated waveguide and the semiconductor nanowire as claimed in claim 1, wherein: the output grating (1) is arranged on the oxide layer (4) and connected with the output end of the coupling waveguide (3), and the end part of the output optical fiber (2) is vertically connected to the output end of the output grating (1).

5. The single longitudinal mode laser with a composite structure based on the on-chip integrated waveguide and the semiconductor nanowire as claimed in claim 1, wherein: the oxide layer (4) is made of silicon dioxide.

6. The single longitudinal mode laser with a composite structure based on the on-chip integrated waveguide and the semiconductor nanowire as claimed in claim 1, wherein: the substrate layer (5) is made of silicon.

7. The single longitudinal mode laser with a composite structure based on the on-chip integrated waveguide and the semiconductor nanowire as claimed in claim 1, wherein: the bent waveguide (6) adopts SiN waveguide or Si and SiO₂And SiC and the like, which are strip waveguides bent into omega shapes.

8. The single longitudinal mode laser with a composite structure based on the on-chip integrated waveguide and the semiconductor nanowire as claimed in claim 1, wherein: the semiconductor nanowire (7) is made of CdS nanowire or ZnO, CdSe, CdTe and other semiconductor nanowires.

9. The single longitudinal mode laser with a composite structure based on the on-chip integrated waveguide and the semiconductor nanowire as claimed in claim 1, wherein: the free space light is a pumping light source and is pulse laser or continuous laser.

10. The single longitudinal mode laser with a composite structure based on the on-chip integrated waveguide and the semiconductor nanowire as claimed in claim 1, wherein: firstly, preparing an on-chip integrated waveguide, then placing a single semiconductor nanowire on an oxide layer (4), carrying out micro-nano scale movement operation on the single semiconductor nanowire, and uniformly contacting two coupling waveguides (3) of the on-chip integrated waveguide to form a Mach-Zehnder interference structure, and preparing to obtain the composite structure single longitudinal mode laser.

Technical Field

The invention relates to the technical field of micro-optical elements, optical communication, photonic integrated circuits and the like, in particular to a composite structure single longitudinal mode laser based on-chip integrated waveguides and semiconductor nanowires.

Background

In the last decade, on-chip micro-nano photonics devices have been widely used in the fields of communication, sensing, quantum computing, etc., and on-chip micro-nano photonics has employed complementary metal oxide semiconductor technology to process a large number of optical devices and optical chips. However, on-chip light sources remain one of the challenges to be addressed. On the other hand, the semiconductor nanowire growing from top to bottom is widely applied to the micro-nano scale laser device. The nanowire lasers are capable of covering a broad spectrum from the ultraviolet band to the near infrared band. The coupling efficiency and repeatability of existing on-chip integrated lasers are low and can generally only be operated in a multi-longitudinal mode, while a single longitudinal mode is crucial for practical application of the on-chip integrated laser.

Disclosure of Invention

In order to solve the problems in the background art, the invention aims to provide a composite structure single longitudinal mode laser based on an on-chip integrated waveguide and a semiconductor nanowire, aiming at the defects of the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the optical waveguide comprises a semiconductor nanowire and an on-chip integrated waveguide, wherein the on-chip integrated waveguide comprises two optical output structures, two coupling waveguides, an oxidation layer, a substrate layer and a bent waveguide; the coupling waveguide, the bent waveguide and the semiconductor nanowire are all arranged on an oxidation layer, a substrate layer is arranged below the oxidation layer, the two ends of the bent waveguide are connected with the coupling waveguide, each coupling waveguide is connected with an optical output structure, each optical output structure comprises an output grating and an output optical fiber which are sequentially connected from the end part of the coupling waveguide, and the two coupling waveguides and the semiconductor nanowire are arranged in a close fit manner to form a single longitudinal mode laser in a Mach-Zehnder interference structure form; free space light is incident on the single longitudinal mode laser with the composite structure to pump the semiconductor nanowire to be above a laser threshold value, light signals are output to two sides through two interference arms formed by the semiconductor nanowire and the bent waveguide, and finally the light signals are vertically output to an output optical fiber through an output grating.

The coupling waveguide is mainly composed of a straight line section positioned in the middle and arc sections arranged at two ends of the straight line section, the straight line section and the semiconductor nanowire are arranged in a close fit mode, and the bending direction of the coupling waveguide is opposite to that of the bending waveguide.

The output light intensity at the output optical fiber is adjusted by adjusting the coupling waveguides with different straight-line segment lengths, and the proportion distribution of the output light intensity at the two output optical fibers is adjusted by designing different lengths and length proportions of the coupling waveguide straight-line segments at the two ends of the on-chip integrated waveguide.

The output grating is arranged on the oxide layer and connected with the output end of the coupling waveguide, and the end part of the output optical fiber is vertically connected with the output end of the output grating.

The oxide layer is silicon dioxide.

The substrate layer is made of silicon.

The bent waveguide adopts an SiN waveguide and is a strip waveguide bent into an omega shape.

The semiconductor nanowire is a CdS nanowire.

The free space light is a pumping light source and is pulse laser.

Drawings

FIG. 1 is a schematic diagram of the structural principle of the present invention;

FIG. 2 is a schematic diagram of a CdS nanowire and SiN bending coupling waveguide composite structure with the same length;

FIG. 3 is a schematic diagram of a curved coupled waveguide structure of the present invention;

FIG. 4 is a microscope image of the same length bend coupled waveguide composite structure of the present invention under pump light excitation;

FIG. 5 is a graph of the laser spectrum of the present invention as the pump intensity increases;

FIG. 6 is a graph of laser threshold before and after coupling of CdS nanowires of the present invention;

FIG. 7 is a schematic view of a composite structure of a different length bend coupled waveguide of the present invention;

FIG. 8 is a microscope image of the composite structure of the present invention with different length bending coupling waveguide excited by pump light.

In the figure: the optical fiber coupling structure comprises an output grating 1, an output optical fiber 2, a coupling waveguide 3, an oxide layer 4, a substrate layer 5, a bent waveguide 6 and a semiconductor nanowire 7.

In the specific implementation, the on-chip integrated waveguide is prepared, then the single semiconductor nanowire is placed on the oxide layer, the single semiconductor nanowire is subjected to movement operation on the micro-nano scale and is in homogeneous contact with the two coupling waveguides of the on-chip integrated waveguide to form a Mach-Zehnder interference structure, and the composite structure single longitudinal mode laser is prepared.

The invention has the beneficial effects that:

the invention has the characteristics of single longitudinal mode, low power consumption, miniaturization, adjustable directional output ratio, stable performance, simple and convenient preparation, simple structure, easy integration and the like. At present, through experimental implementation, the scheme of the invention obtains single-mode laser output with the wavelength of 519nm and the full width at half maximum of 0.1 nm.

Meanwhile, the invention can realize the adjustment of the directional output ratio of 10 to 90 percent through the coupling waveguides with different lengths.