JPH01140124A - Optical device - Google Patents

Abstract

PURPOSE:To permit selection of a specified wavelength and to permit also transformation from TE mode to TM mode optionally by prepg. a relief type diffraction grating having periodicity on the surface of an optical waveguide, coating liquid crystals thereon, depositing Al vapor, and interposing the product between glass plates. CONSTITUTION:An optical waveguide 1 is formed by an ion exchange process on the surface of a glass substrate 3 having a rear surface deposited with Al vapor. A photoresist is coated on the front surface, and a diffraction grating pattern of the resist is formed by the interferential exposure after baking the coated photoresist. The formed diffraction grating pattern is masked, and relief type diffraction grating having each specified period and depth is formed on the surface of the optical waveguide by dry etching. Nematic liquid crystals are poured on the surface of the relief type diffraction grating after providing spacers, then the surface is interposed between glass plates 5 having surfaces deposited with Al vapor. By this constitution, an optical waveguide permitting selective transmission of light having a specified wavelength, permitting also optional transformation from TE mode to TM mode is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical device, and particularly to wavelength selection and TE-T
The present invention relates to an optical device characterized in that M-move selection is performed simultaneously.

[Conventional technology]

Conventionally, an example of selecting between TE mode and 7M mode by loading calcite on an ion-exchange glass waveguide is as follows.
Applied Optics, Vol. 13 (1,974), pp. 1753-1754 (^ppHed Optics voJ, 13 (1974) p.
p1753-ρρ1754)6
[Problems to be Solved by the Invention] In the above prior art, the TE-TM mode selectivity is determined by the relative position between the optical axis of the anisotropic optical crystal and the optical waveguide direction, and the TE-TM mode selectivity is could not be switched arbitrarily. Furthermore, it was difficult to manufacture a combination with an element having wavelength selectivity.

An object of the present invention is to solve the problems of the above-mentioned prior art and provide an optical device that has wavelength selectivity and can arbitrarily select the TE-7M mode.

[Means for solving problems]

The above object is achieved by providing a periodic component on the surface of the optical waveguide and forming a material exhibiting an anisotropic optical effect, such as liquid crystal, on the surface.

[Effect]

For example, a relief-type diffraction grating having a period on the order of submicrons is fabricated on the surface of the optical waveguide, and by applying liquid crystal thereon, the liquid crystal is oriented as shown in FIG. 2(a). Furthermore, when this liquid crystal is sandwiched between glasses and an electric field is applied, the orientation changes as shown in FIG. 3(b). The liquid crystal is
e nep with optical anisotropy as shown in Figure 4.
nO is the refractive index for each direction, ne>
No. Therefore, the refractive index of the leading waveguide nx@no<n
By setting s(ne e, when an electric field is applied, TE
Modes are selectively guided, and the 7M mode is guided into the liquid crystal and scattered. Conversely, when no electric field is applied, the 7M mode is selectively guided, and the TE mode is guided and scattered in the liquid crystal.

In this way, it has wavelength selectivity and furthermore the TE-7M
It is possible to fabricate an optical waveguide whose mode can be arbitrarily selected.

〔Example〕

A first embodiment of the present invention will be described below with reference to FIG.

An optical waveguide 1 (refractive index 1.526) is formed by an ion exchange method on the surface of a glass substrate 3 (refractive index 1.512 for light with a wavelength of 633 Nm) whose back surface is not deposited with AQ. Next, a photoresist is applied to the surface, and after baking, a diffraction grating pattern of the resist is formed by interference exposure method. Using this as a mask, a relief type diffraction grating having a period of 0.2 μm and a depth of 0.1 μm is formed on the surface of the leading waveguide by dry etching. Next, after providing a spacer of 3 to 5 μm and pouring nematic liquid crystal 2 (nII=1.629.no=1.501) onto the surface of the relief type diffraction grating, the surface was covered with a glass plate 5 without AQ deposition. As a result, we were able to create an optical waveguide that selectively transmits light with a wavelength of ~0.6 μm and can also arbitrarily switch the TE-7M mode.The selected wavelength is 1 diffraction. A second embodiment of the present invention will be described with reference to FIG. 2, which allows arbitrary selection of the zeroth order by changing the period of the grating. The second embodiment differs from the first embodiment in that a step is provided in a part of the glass substrate 3, and a semiconductor laser is fitted into the step in a hybrid manner. The semiconductor laser has an active M9. After laminating the upper cladding layer 10, p(IIIffi pole 12 and N
This is a Fabry-Perot type laser in which side electrodes 13 are provided at the top and bottom.

By passing the light from the semiconductor laser through the waveguide, a specific wavelength determined by the period of the diffraction grating is selected. Furthermore, by applying an electric field to the waveguide section, the TE mode is set. 7M mode is selected and output from the right side of the waveguide. In this way, TE-
The 7M mode can be selected arbitrarily, and the wavelength purity is excellent. We were able to obtain a hybrid semiconductor laser.

Next, a third embodiment of the present invention will be explained with reference to FIG.

The third example differs from the first example in that an upper waveguide (refractive index 1.650) is provided below the glass plate 5 (refractive index 1.512). As a result, when 7M mode light enters from the left end of the optical waveguide 1, the light will be emitted from the right end of the optical waveguide 1 if no electric field is applied, and will be emitted from the right end of the upper optical waveguide 14 if an electric field is applied. . In this way, it was possible to produce an optical switch that can change the light emission position in the depth direction of the substrate depending on the presence or absence of an electric field.

〔Effect of the invention〕

According to the present invention, the present invention has wavelength selectivity;

A leading waveguide capable of arbitrarily switching the T E-'r M mode can be easily produced.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a first embodiment of the invention, FIG. 2 is a diagram showing a second embodiment of the invention, FIGS. 3 and 4 are detailed explanatory diagrams of the invention, Figure 5 is. It is a figure which shows the 3rd Example of this invention. DESCRIPTION OF SYMBOLS 1... Optical waveguide, 2... Liquid crystal, 3... Glass substrate, 4... Lower electrode, 5... Glass plate, 6... Upper electrode, 7... Power supply, 8...・Switch, 9... Active layer, 1o... Upper cladding layer, 11... Lower cladding layer, 12... I) side @ pole, ]3... P-side electrode, 1
4... Upper waveguide.

Claims (1)

[Claims] 1. A waveguide region for guiding light is formed in a first portion having periodic irregularities and in contact with the first portion, and has an anisotropic optical effect. an optical device comprising: a second portion; 2. In the optical device according to claim 1,
An optical device characterized in that the second portion is formed of liquid crystal.