CN2729756Y - Polymer waveguide electrooptical modulator of vertical laminated - Google Patents

Abstract

The utility model discloses a vertically superposed polymer waveguide electro-optical modulator which comprises a wave limiting waveguide, a multiple mould guided wave waveguide, and a pair of modulating electrodes. The vertically superposed polymer waveguide electro-optical modulator is characterized in that the multiple mould guided wave waveguide and the wave limiting waveguide are vertically superposed, and moreover, a cushioning layer is arranged between the multiple mould guided wave waveguide and the wave limiting waveguide. A covering layer is arranged above the multiple mould guided wave waveguide, and the modulating electrodes are arranged above the covering layer, wherein the wave limiting waveguide, the multiple mould guided wave waveguide, the cushioning layer and the covering layer are all made of polymeric materials. The utility model has the advantage that the polymer waveguide electro-optic modulator adopts multimode lightguide in design, can be effectively applied to short distance multimode waveguide and multimode fibre systems, and has small coupling loss. Due to the adoption of a vertical structure, the packing density is high. The utility model has a large modulation depth, and preliminary experimental results indicate that the modulation depth at 1300 nm is 91 percent which is a very high modulation depth for a multiple mould electro-optic modulator.

Description

The polymer waveguide electrooptic modulator of vertically stacked

One, technical field

The utility model relates to a kind of waveguide modulator, specifically is a kind of polymer waveguide electrooptic modulator of vertically stacked, can be applicable in the short distance transmission in the multimode lightguide and multimode optical fiber systems.

Two, background technology

The research of electric light (EO) polymkeric substance high-speed modulator starts from the nineties, develops very rapidly, and high frequency organic polymer electrooptic modulator not only can be used for traditional optical communication system, remote sensing, and can be used for producing the laser instrument that meets the DWDM wavelength.Concerning the optical-fiber network in future, the integrated development trend that is inevitable, therefore size of devices being required will be more and more harsher.So there is the polymer waveguide modulator of high integration that market application foreground widely will be arranged.

At present, most polymer modulator in the signal transmission of this long distance, for fear of the pulse strenching that causes owing to modal dispersion, must adopt single mode waveguide optical fiber at long-range smooth pricker Communication System Design.So this modulator is based on the electrooptic modulator of monomode optical waveguide, wherein directional coupler electrooptic modulator and M-Z interferometric modulator are topmost two kinds of structures.The directional coupler electrooptic modulator is to make 1 pair of slab waveguide and 1 pair of electrode on the substrate of electrooptical material (as LiNbO3, compound semiconductor, organic polymer), when making alive not, it is the directional coupler with 2 waveguides and 4 ports, two optical waveguide is parallel and distance is very little, the luminous energy of a waveguide is coupled in another waveguide, the Electrode Field effect is to change the propagation characteristic of waveguide and promote the lateral light between two waveguides to be coupled, along with institute's making alive periodically changes, the also variation of generating period of the coupling of light between two waveguides.Therefore light signal just has been subjected to the modulation of control voltage.The M-Z interferometric modulator is to use two wave frequency is identical but interferometer that the phase place difference is interfered, and the variation that impressed voltage is introduced phase place can be converted to the variation of amplitude.In ideal conditions, input optical power transmits in input point mean allocation to two branch, and interferes at output terminal, so this structure is being played the part of an interferometric effect, its output amplitude is relevant with the phase differential of two branched optical cable passages.Two desirable back-to-back phase-modulators under the effect of electric field, can change the phase place for the treatment of modulation transmissions light in two branches outside.Because it is opposite to be added in two branches electric field, so refractive index in two branches and phase change are also opposite, so refractive index in two branches and phase change are also opposite, so light signal just has been subjected to the modulation of control voltage.

Three, summary of the invention

The purpose of this utility model is to adopt new vertical waveguiding structure to make the polymer waveguide electrooptic modulator of vertically stacked, it can be effectively applied in short distance multimode waveguide and the multimode optical fiber systems, depth of modulation and less coupling loss are preferably arranged, and can improve the packing density of device greatly.

The purpose of this utility model is achieved in that a kind of polymer waveguide electrooptic modulator of vertically stacked, it comprises wave-limiting waveguide, the waveguide of multimode guided wave and a pair of modulator electrode, it is characterized in that waveguide of multimode guided wave and wave-limiting waveguide vertically stacked, and be provided with cushion between the two, be provided with overlayer above the waveguide of multimode guided wave, modulator electrode is located at tectal top.

When smooth wave-limiting waveguide is designed to very high loss (being about 26dB/cm), this just can make the luminous energy that is coupled out from the guided wave waveguide effectively be sponged.

The Mode Coupling equation can be expressed as:

$\frac{{\mathrm{dA}}_{\mathrm{jm}}}{\mathrm{dz}}={\mathrm{i\β}}_{\mathrm{jm}}{A}_{\mathrm{jm}}+k_{\mathrm{jm},j^{\′}{m}^{\′}}{B}_{j^{\′}{m}^{\′}},$

$\frac{{\mathrm{dB}}_{j^{\′}{m}^{\′}}}{\mathrm{dz}}=i{\mathrm{\β}}_{j^{\′}{m}^{\′}}{B}_{j^{\′}{m}^{\′}}+k_{j^{\′}{m}^{\′},\mathrm{jm}}{A}_{\mathrm{jm}}-{\mathrm{\α}}_{j^{\′}{m}^{\′}}{B}_{j^{\′}{m}^{\′}},$

The A here _Jm(j.m) pattern that corresponding is in the guided wave waveguide, and B _{J ' m '}Corresponding is in the wave-limiting waveguide (j ', m ') pattern.Coupling constant between guided wave waveguide and the wave-limiting waveguide can be expressed as:

$k_{j^{\&prime;}{m}^{\&prime;},\mathrm{jm}}=\frac{{\mathrm{\&omega;\&Delta;<figure-callout\; id="2"\; label="n"\; filenames="Y20042006241000081.png"\; state="\{\{state\}\}">n</figure-callout>}}^2}{4}\underset{A}{\&Integral;}{E}_{\mathrm{jm}}^a\left(y\right)E_{j^{\&prime;}{m}^{\&prime;}}^b\left(y\right)\mathrm{dy},$

The pattern of transmitting in the guided wave waveguide (j, m) and the coupling coefficient between the pattern of in wave-limiting waveguide, transmitting (j ' m ') can be expressed as:

$D_{\mathrm{jm},j^{\&prime;}{m}^{\&prime;}}=\frac{k_{j^{\&prime;}{m}^{\&prime;},\mathrm{<figure-callout\; id="2"\; label="jm"\; filenames="Y20042006241000081.png"\; state="\{\{state\}\}">jm</figure-callout>}}^2}{{\mathrm{\&psi;}}_{\mathrm{jm},j^{\&prime;}{m}^{\&prime;}}^2}(1-e^{-a_{j^{\&prime;}m}\&prime;L})\&CenterDot;{\sin }^2\left({\mathrm{\&psi;}}_{\mathrm{jm},j^{\&prime;}{m}^{\&prime;}}L\right),$

The α here _{J ' m '}It is the loss factor of pattern (j ' m ').

The pattern that the pattern of transmitting from wave-limiting waveguide (j ' m ') is transmitted in the guided wave waveguide (j, degeneration factor m) can be expressed as:

${\mathrm{\&eta;}}_{j^{\&prime;}{m}^{\&prime;},\mathrm{jm}}^{\mathrm{\&alpha;}}=\frac{k_{j^{\&prime;}{m}^{\&prime;},\mathrm{<figure-callout\; id="2"\; label="jm"\; filenames="Y20042006241000081.png"\; state="\{\{state\}\}">jm</figure-callout>}}^2}{{\mathrm{\&psi;}}_{\mathrm{jm},j^{\&prime;}{m}^{\&prime;}}^2}{e}^{-{\mathrm{\&alpha;}}_{j^{\&prime;}{m}^{\&prime;}}L}\&CenterDot;s{\mathrm{in}}^2\left({\mathrm{\&psi;}}_{\mathrm{jm},j^{\&prime;}{m}^{\&prime;}}L\right),$

It is pointed out that if α _{J ' m '}Enough high, and the pattern that the pattern of transmitting from wave-limiting waveguide (j ' m ') is transmitted in the guided wave waveguide (j, degeneration factor m) is very little, has so just realized unidirectional couplings.

Electrode by design is controlled the phase-matching condition that is coupled between guided wave waveguide and the wave-limiting waveguide.Two ducting layers of the utility model vertically are provided with, and two ducting layers in the existing coplane device are realized in same layer, so packing density of the present invention (number of unit space internal modulator) can exceed much than the waveguide device of existing coplanar structure.

The utility model compared with prior art, its remarkable advantage is: 1, polymer waveguide electrooptic modulator described in the utility model has adopted multimode lightguide in design, make it can be effectively applied to have less coupling loss in short distance multimode waveguide and the multimode optical fiber systems.2, adopted vertical stratification, so the packing density height.3, depth of modulation is preferably arranged, preliminary experimental result shows that the depth of modulation at the 1300nm place is 91%, and for the multimode electrooptic modulator, this is a very high depth of modulation.

Four, description of drawings

Fig. 1 is a structural representation of the present utility model.

Fig. 2 is the dynamic response of the utility model at the 1330nm place.

Wherein top curve is the modulation signal of 10KHz.

Five, embodiment

The polymer waveguide electrooptic modulator of the vertically stacked that the utility model designs and produces, it comprises wave-limiting waveguide 1, the waveguide 2 of multimode guided wave and modulator electrode 3.Wherein, multimode guided wave waveguide 2 is arranged on the top of wave-limiting waveguide 1, and modulator electrode 3 is arranged on the top of multimode guided wave waveguide 2; Between waveguide 2 of multimode guided wave and wave-limiting waveguide 1, be provided with cushion 4, between modulator electrode 3 and multimode guided wave waveguide 2, be provided with overlayer 5.The structure of whole modulator is the vertical symmetry shape.

The lithographic printing of in VLSI (very large scale integrated circuit) is made, using that modulator described in the utility model, its manufacture craft flow process follow conventional lines.Concrete method for making is:

Chromium that one deck 130 are thick and the thick gold of one deck 2000 at first are deposited on the silicon wafer as bottom electrode.The chromium layer is in order to strengthen the adhesion between gold layer and the bottom cover layer.Then the thick covering polymeric material of spin coating last layer 2.2 μ m is done under-clad layer, and its refractive index is 1.51 under the TM of 1330nm place polarization.

The core layer polymer material that spin coating last layer 5.1 μ m are thick is as the plane wave-limiting waveguide again, and its refractive index is 1.57 under the TM of 1330nm place polarization.

Next the polymeric material that spin coating last layer 2.7 μ m are thick is as cushion, and the refractive index of this polymkeric substance is 1.54 under the wavelength 1330nm TM of place polarization.

Next the core layer polymer material that spin coating last layer 5.1 μ m are thick is as core layer again.

At the thick gold of deposited on top one deck 2000 of this core layer, it plays the effect of polarized electrode.

Above-mentioned sample is polarized under 113 ℃ temperature, and this temperature is the glass transition temperature of core layer polymer material, directly contacts polarization under the DC voltage of 800V.Nonlinear factor γ ₃₃Be measured as 12pm/V.

After directly contact polarizes, this layer top electrodes removed with the wet etching method, formed the guided wave waveguide.

Again the ultraviolet photoresist that spin coating last layer 2.6 μ m are thick is as top cover layer, and its refractive index is 1.49 at the TM of 1330nm place polarization.

At last after photoetching and this twice process of wet etching, in top deposit pair of electrodes again, the modulator electrode of Here it is electrooptic modulator.

Claims (2)

1, a kind of polymer waveguide electrooptic modulator of vertically stacked, it comprises wave-limiting waveguide (1), multimode guided wave waveguide (2) and modulator electrode (3), it is characterized in that multimode guided wave waveguide (2) and wave-limiting waveguide (1) are vertically stacked, and be provided with cushion (4) between the two, be provided with overlayer (5) in the top of multimode guided wave waveguide (2), modulator electrode (3) is located at the top of overlayer (5).

2, the polymer waveguide electrooptic modulator of vertically stacked according to claim 1 is characterized in that wave-limiting waveguide (1), multimode guided wave waveguide (2), cushion (4) and overlayer (5) are to be made by polymeric material.

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