JPS5859401A - Optical waveguide polarizer - Google Patents

Abstract

PURPOSE:To obtain a polarizer which is a thin film and has the flat wavelength characteristics, by providing a minute conductive grating, which has a pitch shorter than the used wavelength, on the end face of an optical fiber or an optical waveguide. CONSTITUTION:A conductive grating 4 is provided across a core 2 and a clad 3. The width and the pitch of the grating are set to values sufficiently shorter than the used wavelength. A gold grating pattern which is produced by the electron beam lithography and has 0.4mum pitch, 0.15mum width, and 1,500Angstrom thickness has about 1/10 extinction ratio from the wavelength of visible rays to 1.3mum, and a grating pattern where the similar grating pattern is produced on this grating pattern after forming an insulating film consisting of SiO2 or the like has 1/100 extinction ratio. Conductive gratings 4 are formed in incidence ends 8 and 9 so that directions of gratings are orthogonal to each other, and light sources are provided in incidence ends 8 and 9 independently of each other, and their outputs are changed, thereby controlling the direction of polarization of the light emitted from an exit end 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention company, Optical Communication Maryo, relates to waveguide polarizers used in various optical functional devices.

For measuring the polarization characteristics of optical fibers or optical circuits, or for applications using polarization systems, A stretched and oriented plastic film containing a cochroic dye was used.

However, the prism (2) is expensive, has a block shape, has a considerable optical thickness, and uses lenses when constructing the optical system. It is complicated, and because it is assembled using pliers, it is susceptible to vibration and is difficult to use. Regarding ■, it is film-like and has a thickness of 810 mm.
For example, when it is installed between the fiber and the 7-iper, it causes a loss due to this distance, and in the near-infrared region used in optical communication, it has a polarization effect. There are no drawbacks.

In order to eliminate these drawbacks, the present invention W14 realizes an optical circuit having a thin film polarized 'yt'lL element with flat wavelength characteristics. The present invention will be explained in detail below with reference to the drawings.

115th! 1I shows an example of an optical fiber having a fine conductive grid on the end surface of the tube, where 1Fi is an optical fiber, J is a core, J is a 2-rad part of a beam, and 3 is a conductive grid. The width and pitch of the conductive grating must be sufficiently small compared to the wavelength used, that is, O1 reference μm for visible range, /, 3μ for Jμm*.
It is necessary that it is no more than a joke.

For example, fabricated by electron beam phosphorography (jimourning pitch O0, width o, itμm, thickness/10
The gold lattice pattern of 0X has an extinction ratio of about 3° from the visible to the It had an extinction ratio of 1 at 0.

The grid can be made of common metals such as gold, chrome, aluminum, and silver.

To make such an optical fiber, for example, several tII optical fibers cut into several lengths are bundled together, the end faces are polished, and the whole is subjected to holographic exposure using electron beam lithography, X-ray phosphorography, or ultraviolet radar. It is better to use photolithography.

If a similar polarizing plate is required on the end face of a long fiber, it may be manufactured directly, but the polarizing plate can be attached by a method such as electrical discharge welding from a short 7-eye to a long 7-eye A. It may be fused with.

Figure λ shows an example of a multiplexing circuit among the planar circuits on the t-i plane of the polarizing element. is the substrate, 6 is the optical path section, 7 is the output end,
1. This is the entrance end. At the incident end L and RI, conductive grids are formed such that the directions of the grids are perpendicular to each other. In this case, if source tubes are provided independently at the input ends r and v and their outputs are changed, the direction of the polarization of the light coming out from the output end 7 can be adjusted.

In the optical circuit according to the present invention, the surface having a polarizer is
Even when connecting to a light source or other optical fiber or optical circuit, since the polarizer layer is extremely thin, normal end-face direct connection is possible, and optical systems such as lenses are unnecessary.

As mentioned above, since the polarizing plate of the optical circuit according to the present invention is extremely thin, it has the advantage that it can be easily connected to a light source, or to other optical devices or optical circuits, and can be used for various optical communication elements. , useful as parts for optical foot measurement.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an optical fiber having a fine conductive grating on a T-face according to the present invention, and FIG. 1 is a perspective view of a waveguide polarizer of the present invention. l...yt, 7aipa, co-core, J...cladding, ≠...conductive lattice,! ... Substrate, 6... Optical path, 7... Outgoing end, L, R... Incoming end.

Claims (1)

[Claims] 1. A waveguide polarizer characterized in that a fine conductive lattice tube with a pitch smaller than the wavelength used is provided on the end face of an optical 7-eyeper or optical waveguide.