Method for generating supercontinuum from communication band to middle infrared based on silicon nitride waveguide

Abstract

The invention discloses a method for generating supercontinuum from the communication band to the middle infrared based on a silicon nitride waveguide. The method comprises the steps of step 1, using an ultrashort pulse light source to emit the light which has a frequency of 8-12MHz, and a central wavelength of 1.4-2.2 micrometer, step 2, conducting lens coupling of ultrashort femtosecond pulses which is then infused into a ridge / groove hybrid reverse silicon nitride waveguide with a flat light dispersion, wherein the structure of the silicon nitride waveguide comprises a silica oxide layer arranged on a silicon plate, the grooves containing a single silica ridge is formed on the surface of the silica. The silicon nitride waveguide applies the structure of the ridge / groove hybrid to make the effect area of the light field small, and achieve a big non-linear coefficient of the waveguide. After high peak power femtosecond optical pulses are introduced into the waveguide, non-linear processes of self phase modulation, cross phase modulation, four-wave mixing, soliton frequency shift, dispersive wave generation and the like occur, and finally the supercontinuum from the communication band to the middle infrared is formed.

Description

Technical field

[0001] The invention relates to the technical field of integrated photonic communication and sensing on an optical chip, in particular to a method for generating a supercontinuum spectrum from the optical communication waveband to the mid-infrared waveband. Background technique

[0002] Supercontinuum spectrum refers to the spectrum in which the light intensity changes continuously with the frequency in a wide frequency range. It is a kind of complex that the spectrum broadens sharply (the broadening can reach tens to thousands of nanometers) when high-intensity pulses pass through nonlinear materials. The nonlinear phenomenon. Because supercontinuum spectroscopy has wide and important applications in many scientific fields such as pulse compression, optical communication, optical coherence tomography, spectral analysis and optical sensing, ultrashort pulse generation and optical frequency combs, it has been an international research hotspot in recent years. . [...

Examples

Embodiment 1

[0034] This embodiment provides a supercontinuum generation method capable of realizing near-infrared to mid-infrared band.

[0035] Such as figure 1 As shown, the silicon nitride waveguide structure in this embodiment includes a silicon dioxide oxide layer 102 disposed on a silicon wafer 101. The silicon dioxide oxide layer 102 is etched on the surface to form a trench 103 containing a single silicon dioxide ridge. The trench 103 on both sides of the ridge silicon dioxide is filled with silicon nitride, and finally a layer of silicon nitride inverted structure 104 is covered on the entire surface of the structure. Its dispersion characteristics and mode field distribution are as follows figure 2 Shown.

[0036] Reference image 3 In specific implementation, the femtosecond laser 301 emits ultrashort optical pulses with a center wavelength of 1.804 microns, a full width at half maximum and a peak power of 50 femtoseconds and 10 kilowatts, respectively, which are composed of a half-...

Embodiment 2

[0040] Such as Figure 5 Shown, based on the non-linear effect in the dispersion flat high non-linear reverse silicon nitride waveguide to achieve supercontinuum, the input optical power changes on the supercontinuum performance example, the femtosecond laser 301 emits a center wavelength of 1.804 microns, half value Ultrashort optical pulses with full width and peak power of 50 femtoseconds and 10 kilowatts respectively, after passing through the polarization control system composed of half-wave plate 302 and polarization beam splitter 303, they are further coupled and injected into ridges / grooves with flat dispersion through lens 304 Slot hybrid inverted silicon nitride waveguide 305, due to the high peak power of the femtosecond pulse, combined with the large nonlinear coefficient of silicon nitride waveguide 305, self-phase modulation, cross-phase modulation, and four-wave mixing occur inside it A series of non-linear processes such as soliton frequency shift and dispersive ...

Technical field

[0001] The invention relates to the technical field of integrated photonic communication and sensing on an optical chip, in particular to a method for generating a supercontinuum spectrum from the optical communication waveband to the mid-infrared waveband. Background technique

[0002] Supercontinuum spectrum refers to the spectrum in which the light intensity changes continuously with the frequency in a wide frequency range. It is a kind of complex that the spectrum broadens sharply (the broadening can reach tens to thousands of nanometers) when high-intensity pulses pass through nonlinear materials. The nonlinear phenomenon. Because supercontinuum spectroscopy has wide and important applications in many scientific fields such as pulse compression, optical communication, optical coherence tomography, spectral analysis and optical sensing, ultrashort pulse generation and optical frequency combs, it has been an international research hotspot in recent years. . [...

Examples

Embodiment 1

[0034] This embodiment provides a supercontinuum generation method capable of realizing near-infrared to mid-infrared band.

[0035] Such as figure 1 As shown, the silicon nitride waveguide structure in this embodiment includes a silicon dioxide oxide layer 102 disposed on a silicon wafer 101. The silicon dioxide oxide layer 102 is etched on the surface to form a trench 103 containing a single silicon dioxide ridge. The trench 103 on both sides of the ridge silicon dioxide is filled with silicon nitride, and finally a layer of silicon nitride inverted structure 104 is covered on the entire surface of the structure. Its dispersion characteristics and mode field distribution are as follows figure 2 Shown.

[0036] Reference image 3 In specific implementation, the femtosecond laser 301 emits ultrashort optical pulses with a center wavelength of 1.804 microns, a full width at half maximum and a peak power of 50 femtoseconds and 10 kilowatts, respectively, which are composed of a half-...

Embodiment 2

[0040] Such as Figure 5 Shown, based on the non-linear effect in the dispersion flat high non-linear reverse silicon nitride waveguide to achieve supercontinuum, the input optical power changes on the supercontinuum performance example, the femtosecond laser 301 emits a center wavelength of 1.804 microns, half value Ultrashort optical pulses with full width and peak power of 50 femtoseconds and 10 kilowatts respectively, after passing through the polarization control system composed of half-wave plate 302 and polarization beam splitter 303, they are further coupled and injected into ridges / grooves with flat dispersion through lens 304 Slot hybrid inverted silicon nitride waveguide 305, due to the high peak power of the femtosecond pulse, combined with the large nonlinear coefficient of silicon nitride waveguide 305, self-phase modulation, cross-phase modulation, and four-wave mixing occur inside it A series of non-linear processes such as soliton frequency shift and dispersive ...

Images