CN100487515C

CN100487515C - Wavelength adjustable filter and its application

Info

Publication number: CN100487515C
Application number: CNB2006100254003A
Authority: CN
Inventors: 许震宇
Original assignee: Tongji University
Current assignee: Tongji University
Priority date: 2006-03-31
Filing date: 2006-03-31
Publication date: 2009-05-13
Anticipated expiration: 2026-03-31
Also published as: CN101046553A

Abstract

The wavelength adjustable filter includes a substrate of piezoelectric material, two photonic crystal set on the substrate with air layer in between, and a control circuit connected to the substrate. The substrate as heat expanding material and the photonic crystal, one dimensional, two dimensional or three dimensional, form one structure serving as one temperature sensor with output light wave in frequency reflecting the change in temperature. The present invention has simple structure, relaxed manufacture condition, great adjustable range and other advantages, and may be used in filtering, light and microwave communication, data memory and other fields.

Description

A kind of wavelength adjustable filter and application thereof

Technical field

The invention belongs to optical device, micro electronmechanical field, relate to wave filter.

Background technology

The eighties in 20th century, John S. and Yablonovitch E. have proposed this new material of photonic crystal, utilize its optical band gap characteristic, can make devices such as low-loss catoptron, optical waveguide, no threshold value laser instrument.People's prediction, photonic crystal will be the variation that optical communication and other association areas are brought essence in the near future.

If the optical band gap characteristic by certain mode active adjustment photonic crystal just can obtain adjustable photonic crystal.The application of this class photonic crystal will be more extensive and flexible.The mode of regulating comprises, the electric field by adding, magnetic field, mechanical load, thermal force or by injecting another kind of material (for example liquid crystal material).

The Sungwon Kim of Korea S has designed the adjustable photon crystal structure of a kind of strain in calendar year 2001, (KimS, Gopalan V, Strain-tunable photonic band gap crystals[J], Appl PhysLett, 2001,78 (20): 3015-3017), see also Fig. 1, be to change the arrangement cycle of 2 D photon crystal (because there is detrusion in the substrate of piezoelectric by the change of shapes of substrates, driving photonic crystal makes hexagonal array originally become pseudo-hexagonal array), to change the position and the width of overall optical band gap (reflection broadband), be that a kind of broadband is regulated.

Existing multilayer dielectric interferes membranous type to close wave filter, be that the high index of refraction dielectric film and the low-refraction dielectric film that have near λ/2 or λ/4 optical thicknesses are alternately overlapped to form film (1-D photon crystal), so show stronger selectivity for specific wavelength.This wavelength selectivity mainly depends on the number of plies of dielectric film, the thickness of film, the material of film etc., and its optical property is immutable after film is made.See also Fig. 2, parts 2 wherein are multilayer film (1-D photon crystal).

Summary of the invention

The wave filter that the purpose of this invention is to provide a kind of simple photon crystal structure can be regulated the transmitted light wavelength quickly and accurately, overcomes the above-mentioned shortcoming of prior art.

For achieving the above object, solution of the present invention is:

A kind of wavelength adjustable filter comprises substrate, is immersed in airborne two photonic crystals, and described two photonic crystals are arranged in the substrate, is the air layer as defective between two photonic crystals.

Further, this substrate is a piezoelectric, and is connected with control circuit.

This substrate is a thermal expansion material.

Described photonic crystal comprises 1-D photon crystal, 2 D photon crystal, three-D photon crystal.

This structure as temperature sensor, is promptly judged variation of temperature by the frequency of output light-wave.

The present invention is similar with Kim structurally, but the arrowband regulate, promptly only allow the single-frequency light wave to pass through.

For example, by the substrate of piezoelectric and be immersed in airborne two 1-D photon crystals and constitute.Air between two 1-D photon crystals can be regarded defect layer as.Like this, defect state (the transmission arrowband in the zone of reflections) will appear in the optical band gap.Referring to Fig. 5, it is that the light of 660nm can pass through that wavelength is arranged in 520-870nm reflective band.

After applying voltage, the distortion by substrate can change two distances between the photonic crystal, thus the optical band gap performance of adjustment structure (being the position of transmission arrowband).Referring to Fig. 6, the light wavelength of transmission originally is 660nm, and the transmission light wavelength becomes 710nm now.

This structure has advantages such as adjustable extent is big, simple in structure, size is little, the response time is short, non-destructive.Except being used for filtering, also can be used for fields such as communication, data storage, demonstration and the photoelectron of light wave or microwave be integrated.Compare with the design of Kim from the structure angle, structure of the present invention is more simple and reliable, manufacture process requirement is low, and promptly the manufacturing technology of 1-D photon crystal is simply ripe, with the bonding structure that can finish the design of substrate.

Description of drawings

Fig. 1 is the adjustable photonic crystal synoptic diagram of two-dimentional strain;

Fig. 2 is that the multilayer dielectric interferes membranous type to close the wave filter synoptic diagram;

Fig. 3 is the perspective view of an embodiment of the present invention;

Fig. 4 is a side schematic view embodiment illustrated in fig. 3;

Fig. 5 is a substrate embodiment illustrated in fig. 3 reflecting spectrum synoptic diagram when not being out of shape;

Fig. 6 is the reflecting spectrum synoptic diagram behind the substrate deformation embodiment illustrated in fig. 3.

Embodiment

Fig. 3 is a kind of embodiment synoptic diagram of the present invention.With substrate is that piezoelectric is an example, comprises piezoelectric substrate 1 and 1-

D photon crystal

2,3 disposed thereon, alternately is made of the transparent material of high low-refraction, and the air layer thickness between two 1-

D photon crystals

2,3 is d.

Two 1-

D photon crystals

2,3 are adhered on the substrate 1, and this substrate 1 is a piezoelectric, and is connected with control circuit.Like this, when the substrate of piezoelectric stretches because of external voltage or can drive photonic crystal on it during compression deformation, change distance between the two, thereby the transmission light frequency is changed.

This structure both can filter out required single-frequency light from the incident light of cline frequency, also can be used as the single-frequency light source, launched single-frequency light continuously.Base material also can change magnetostriction materials (promptly by externally-applied magnetic field the shape of substrate being changed) etc. into.If substrate is thermal expansion material (promptly be heated and can expand, catch a cold and can shrink, plain metal all has this character), then this structure can also be used as temperature sensor, and promptly variation of temperature can be judged by the frequency of output light-wave.

1-

D photon crystal

2,3 in the structure can also replace with two dimension or three-D photon crystal, also can obtain identical effect.

Corresponding to the different base material that is adopted, comprise piezoelectric, magnetostriction materials, mechanical-stretching material, thermal expansion material, the mode of regulating comprises, the electric field by adding, magnetic field, mechanical load, thermal force or by injecting another kind of material (for example liquid crystal material).

Realize preferred mode of the present invention, to be filtered into example

High index of refraction is got 2.5 (refractive indexes of ZnSe), and low-refraction is 1.37 (refractive indexes of MgF2).The refractive index of air layer is 1.

Make that 1-D photon crystal is a film system, be centre wavelength, be taken as 650nm.So the thickness of high refractive index layer is 54.2nm, the thickness of low-index layer is 162.5nm.The cycle of this photonic crystal is a=216.7nm.Making the piezoelectric substrate not be out of shape the space-time thickness of gas is 0.1a, for the light of vertical incidence, the reflecting spectrum of this moment as shown in Figure 5, promptly having only wavelength this moment is that the light-wave transmission of 660nm passes through.

Make substrate deformation (instantaneous finishing) if apply voltage, thereby make the thickness Change Example such as the 0.5a of air layer, then reflecting spectrum as shown in Figure 6.At this moment, the wavelength of transmitted light wave is 710nm.Promptly, just can regulate the wavelength of transmitted light wave, thereby realize the effect of filtering by regulation voltage.

The above-mentioned description to embodiment is can understand and apply the invention for ease of those skilled in the art.The person skilled in the art obviously can easily make various modifications to these embodiment, and needn't pass through performing creative labour being applied in the General Principle of this explanation among other embodiment.Therefore, the invention is not restricted to the embodiment here, those skilled in the art should be within protection scope of the present invention for improvement and modification that the present invention makes according to announcement of the present invention.

Claims

1, a kind of wavelength adjustable filter is characterized in that: comprise substrate, be immersed in airborne two photonic crystals, described two photonic crystals are arranged in the substrate, have air layer between two photonic crystals; This substrate is a piezoelectric, and is connected with control circuit; Described photonic crystal comprises 1-D photon crystal, 2 D photon crystal or three-D photon crystal.

2, a kind of wavelength adjustable filter is characterized in that: comprise substrate, be immersed in airborne two photonic crystals, described two photonic crystals are arranged in the substrate, have air layer between two photonic crystals; This substrate is a thermal expansion material; Described photonic crystal comprises 1-D photon crystal, 2 D photon crystal or three-D photon crystal.

3, the application of wavelength adjustable filter according to claim 2 is characterized in that: this wavelength adjustable filter as temperature sensor, is promptly judged variation of temperature by the frequency of output light-wave.