AN ATHERMAL ARRAYED WAVEGUIDE GRATING

Abstract

An athermal arrayed waveguide grating includes a silicon-based substrate and an athermal arrayed waveguide disposed on the silicon-based substrate. The athermal arrayed waveguide includes a cladding layer and a waveguide chip layer, the waveguide chip layer is disposed on the cladding layer and has a refractive index greater than that of the cladding layer; the waveguide core layer includes multilayer structures having a periodic configuration, the multilayer structure includes two layers of silica material and a negative temperature coefficient material disposed between the two layers of silica material; the negative temperature coefficient material is used to compensate for a dimensional deformation of the silicon-based substrate after being heated. The present invention simplifies the structure of the athermal arrayed waveguide grating, sets the negative temperature coefficient material in the waveguide core layer structure, and makes the final temperature coefficient of refractive index of the waveguide structure is a negative number.

Claims

1. An athermal arrayed waveguide grating, characterized in that including: a silicon-based substrate; and the following structure disposed on the silicon-based substrate: at least one input waveguide for inputting optical signal; a first free transmission region, composed of a first planar waveguide and coupled with the output end of the input waveguide; an athermal arrayed waveguide, coupled with the output end of the first free transmission region; a second free transmission region, composed of a second planar waveguide and coupled with the output end of the athermal arrayed waveguide; at least one output waveguide for outputting optical signal, coupled with the output end of the second free transmission region; the athermal arrayed waveguide comprises a cladding layer and a waveguide core layer, the waveguide core layer is disposed in the cladding layer and has a refractive index greater than that of the cladding layer; the waveguide core layer comprises multilayer structures having a periodic configuration, the multilayer structure comprises two layers of silica material and a negative temperature coefficient material disposed between the two layers of silica material; the negative temperature coefficient material is used to compensate for a dimensional deformation of the silicon-based substrate after being heated, so as to reduce the temperature drift coefficient of the athermal arrayed waveguide grating.

2. The athermal arrayed waveguide grating to claim 1, characterized in that the negative temperature coefficient material is titanium dioxide.

3. The athermal arrayed waveguide grating to claim 2, characterized in that in the multilayer structure, the thickness of the silica material is 0.5-1 μm, and the thickness of the titanium dioxide is 0.05-0.1 μm.

4. The athermal arrayed waveguide grating to claim 1, characterized in that the effective refractive index of the multilayer structure is 1.5-1.6.

5. The athermal arrayed waveguide grating to claim 1, characterized in that the effective temperature coefficient of refractive index of the multilayer structure is −2e.sup.−6-−4e.sup.−6/k.

6. The athermal arrayed waveguide grating to claim 1, characterized in that the thickness of the negative temperature coefficient material is related to the optimal effective refractive index of the waveguide core layer.

7. The athermal arrayed waveguide grating to claim 1, characterized in that the thickness of the negative temperature coefficient material is related to the optimal effective temperature coefficient of refractive index of the waveguide core layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a structural diagram depicting the athermal arrayed waveguide grating in embodiment 1 of the present invention, where, 10-multilayer structures, 11-silica material, 12-negative temperature coefficient material, 30-silica cladding layer.

[0027] FIG. 2 is a structural diagram depicting the athermal arrayed waveguide grating in embodiment 2 of the present invention, where, 101-input waveguide, 102-output waveguide, 103-first free transmission region, 104-second free transmission, 105-athermal arrayed waveguide, 140-silicon-based substrate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Specific embodiments of the present invention are described in further detail in combination with the related drawings and embodiments below. However, in addition to the descriptions given below, the present invention can be applied to other embodiments, and the scope of the present invention is not limited by such, rather by the scope of the claims.

Embodiment 1

[0029] Referring to FIG. 1, which shows an athermal arrayed waveguide, including a silica cladding layer (30) and a waveguide core layer disposed in the cladding layer (30), the waveguide core layer comprises multilayer structure (10), which comprises two layers of silica material (11) and negative temperature coefficient material (12) disposed between the two layers of silica material; the negative temperature coefficient material (12) is used to compensate for a dimensional deformation of the silicon-based substrate (140) after being heated, so as to reduce the temperature drift coefficient of the athermal arrayed waveguide grating.

[0030] In this embodiment, the refractive index of the waveguide core layer is greater than that of the silica cladding layer (30).

[0031] In the embodiment, the negative temperature coefficient material (12) is titanium dioxide.

[0032] In the embodiment, in the multilayer structure (10), the thickness of the silica material (11) is 0.5-1 μm, and the thickness of the titanium dioxide (12) is 0.05-0.1 μm. The thickness of the negative temperature coefficient material (12) is related to the optimal effective refractive index of the waveguide core layer. For example, when the thickness of the silica material (11) is 1 μm, the thickness of the titanium dioxide (12) is 0.1, and the thickness of the multilayer structure (10) is 4.2 μm: the effective refractive index of the silica material (11) is 1.476, and of which the effective temperature coefficient of refractive index is 7.6e.sup.−6/k; the effective refractive index of the titanium dioxide (12) is 2.614, and of which the effective temperature coefficient of refractive index is −1.2e.sup.−4/k; the effective refractive index of the multilayer structure (10) is 1.5795, and of which the effective temperature coefficient of refractive index is −4e.sup.−6/k.

[0033] In other embodiments, the effective refractive index of the multilayer structure (10) is 1.5-1.6.

[0034] In other embodiments, the optimal effective temperature coefficient of refractive index of the waveguide core layer is −2e.sup.−6-−4e.sup.−6/k.

[0035] A two-period multilayer structure (10) is shown in the embodiment depicted in FIG. 1, but the number and thickness of the multilayer structure (10) in the present invention is not limited to this embodiment.

Embodiment 2

[0036] Referring to FIG. 2, the present invention also shows an athermal arrayed waveguide grating device, which includes a silicon-based substrate (140), and the following structure disposed on the silicon-based substrate (140): [0037] one input waveguide (101) for inputting optical signal; [0038] a first free transmission region (103), composed of a first planar waveguide and coupled with the output end of the input waveguide (101); [0039] the athermal arrayed waveguide (105) shown in the embodiment 1, coupled with the output end of the first free transmission region (103); [0040] a second free transmission region (104), composed of a second planar waveguide and coupled with the output end of the athermal arrayed waveguide (105); [0041] and at least one output waveguide (102) for outputting optical signal, coupled with the output end of the second free transmission region (104).

[0042] The temperature drift coefficient of the central wavelength of the grating device with the waveguide structure above is calculated as −0.0014 nm/deg, while the temperature drift coefficient of the central wavelength of the arrayed waveguide grating with silicon-based silica substrate is calculated as 0.012 nm/deg, which is reduced by one order of magnitude.

[0043] The present invention makes the waveguide get a negative temperature characteristic by improving the design of the waveguide structure, so as to eliminate the influence caused by the thermal expansion coefficient of silicon-based materials in the grating device, greatly reduce the overall temperature drift coefficient of the arrayed waveguide grating device, and improve the performance of the device.

[0044] The technical features of the above embodiments can be combined arbitrarily, in order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction between the combination of these technical features, they shall be considered to be within the scope of this specification.

[0045] The present invention only described several above embodiments, which are described more specific and detailed, but it cannot be understood as a limitation on the scope of the present invention. It should be pointed out that for ordinary technical personnel in the art, without departing from the concept of the present invention, a number of deformation and improvements can be made, which belong to the scope of the present invention. Therefore, the scope of the present invention shall be subject to the recorded claims.