JPH0339913A - Light wavelength converting device - Google Patents

Abstract

PURPOSE:To couple laser light directly and optically without interposing an optical system such as a lens in a light wavelength converting element from a semiconductor laser chip while protecting the active layer end surface of a semiconductor laser and an optical waveguide end surface by making the active layer end surface of the semiconductor laser and the optical waveguide end surface abut on each other across a gap provided on the active layer end surface and optical waveguide end surface. CONSTITUTION:Laser light which is excited and oscillated in the active layer 7 is emitted from the end surface of the active layer 7 and made incident on the optical waveguide 9 through the gap 10 provided between the active layer 7 and optical waveguide 9. At this time, the end surface of the active layer 7 and the end surface of the optical waveguide 9 is not in contact with nowhere and are protected. Thus, the light wavelength converting device consists of the semiconductor laser and the optical waveguide which has a light wavelength converting function based upon nonlinear optical effect and the active layer end surface of the semiconductor laser and the optical waveguide end surface are made to abut on each other across the gap provided on the active layer end surface of the semiconductor laser or the optical waveguide end surface to enable direct optical coupling while protecting the active layer end surface and optical waveguide end surface.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an optical wavelength conversion device that converts the wavelength of semiconductor laser light using a nonlinear optical effect.

2. Description of the Related Art Conventional optical wavelength conversion devices have a structure in which laser light emitted from a semiconductor laser is focused through a lens and then input into an optical waveguide (for example, see Japanese Patent Laid-Open No. 18934/1983). .

An example of the conventional optical wavelength conversion device mentioned above will be described below with reference to the drawings.

FIG. 5 is a diagram showing the configuration of a conventional optical wavelength conversion device. In FIG. 5, 1 is a semiconductor laser. 2 is a collimator lens, and 3 is a condenser lens. 4 is an optical wavelength conversion element, for example, LiNb0. An optical waveguide 5 is provided on a substrate (see Japanese Unexamined Patent Publication No. 61-72222, etc.).

The operation of the optical wavelength conversion device configured as described above will be described below.

First, a laser beam emitted from a semiconductor laser 1 is turned into a parallel beam by a collimator lens 2.

Furthermore, this parallel beam is converged by a condensing lens 3,
The light enters an optical waveguide 5 provided in the optical wavelength conversion element 4. The wavelength of this incident light is converted by the nonlinear optical effect of the optical waveguide 5.

Problems to be Solved by the Invention However, in the above configuration, the laser light emitted from the semiconductor laser 1 once passes through the semiconductor laser 1 and the optical waveguide 5.
Since the light enters the optical waveguide 5 after propagating through the space between the light and the light, losses such as vignetting and reflection due to the lenses present in the middle occur. Further, the collimator lens 2 and the condensing lens 3 have drawbacks such as increasing costs.

In order to overcome this drawback, it has been considered to butt the semiconductor laser chip and the optical waveguide together for direct optical coupling, but with this method, the laser end face and the optical waveguide end face may come into contact and be damaged during indirect adjustment between the end faces. There remains the problem that this occurs.

In view of the above problems, the present invention provides an optical wavelength conversion device that does not use an optical system between the semiconductor laser and the optical wavelength conversion element and can protect the laser end face and the optical waveguide end face.

In order to solve the two-pronged problem, the optical wavelength conversion device of the present invention is an optical wavelength conversion device consisting of a semiconductor laser and an optical waveguide having an optical wavelength conversion function based on a nonlinear optical effect. , the end face of the active layer of the semiconductor laser and the end face of the optical waveguide are brought into contact with each other with a gap provided between the end face of the active layer of the semiconductor laser or the end face of the optical waveguide.

Further, the active layer of the semiconductor laser and the optical waveguide may be arranged in parallel with a gap of less than the wavelength.

Operation According to the present invention, the active layer end face of the semiconductor laser and the optical waveguide end face are butted against each other with a gap in between, so that they do not come into contact with each other and can be directly optically coupled in a protected state.

Therefore, an optical system between the semiconductor laser and the optical waveguide becomes unnecessary, and the end face can also be protected.

Furthermore, when the active layer of the semiconductor laser and the optical waveguide are arranged in parallel with a gap of less than the wavelength, the electromagnetic field distribution of the laser light in the active layer of the semiconductor laser will spread across the gap between the active layer and the optical waveguide. The laser light propagates from the active layer to the optical waveguide by leaking beyond the active layer and into the optical waveguide. That is, the electromagnetic field distribution in the active layer has a distribution that decreases exponentially with distance even in the medium outside the active layer, and on the other hand, laser light traveling in an optical waveguide also has a unique electromagnetic field distribution. Therefore, if these electromagnetic field distributions can be phase-matched and the medium between the active layer and the optical waveguide is thinner than the wavelength, light leaks from the active layer to the optical waveguide. arise. Therefore, an optical system between the semiconductor laser and the optical wavelength conversion element is not required. In addition, the end faces do not come into contact with each other, making it possible to protect them.

Embodiments Hereinafter, optical wavelength conversion devices according to embodiments of the present invention will be described with reference to the drawings.

1 and 2 show the configuration of an optical wavelength conversion device in a first embodiment of the present invention. 6 is a semiconductor laser chip, and 7 is its active layer. Reference numeral 8 denotes an optical wavelength conversion element, which is made of, for example, LiNbo and has an optical waveguide 9 provided on a substrate. 10 is a gap, and the tip of the active layer 7 or the optical waveguide 9 is removed by J.
It is formed by depositing a thin film on other parts.

The operation of the optical wavelength conversion device configured as described above will be explained. First, the laser light excited and oscillated within the active layer 7 is emitted from the end face of the active layer 7.

The light enters the optical waveguide 9 through a gap 10 provided between the active layer 7 and the optical waveguide 9. At this time, the end face of the active layer 7 and the end face of the optical waveguide 9 are protected without contacting anywhere.

As described above, according to this embodiment, in an optical wavelength conversion device including a semiconductor laser and an optical waveguide having an optical wavelength conversion function based on a nonlinear optical effect, the active layer end face of the semiconductor laser and the optical waveguide end face are connected to each other. By sandwiching and abutting the end faces of the active layer of the semiconductor laser or the end face of the optical waveguide, direct optical coupling can be achieved while protecting the end faces of the active layer and the end face of the optical waveguide.

Next, regarding the optical wavelength conversion device of the second embodiment of the present invention,
This will be explained with reference to FIGS. 3 and 4.

In FIGS. 3 and 4, the same numbers as those in FIGS. 1 and 2 indicate the same components. A semiconductor laser chip 6 has an active layer and an optical waveguide 9 placed on an optical wavelength conversion element 8 with a gap therebetween. They are arranged so that they are parallel to each other. That is, as shown in FIG. 4, 11 and 12 are cladding layers provided on both sides of the active layer 7 of the semiconductor laser chip 6, and the thickness of the cladding layer 12 between the active layer 7 and the optical waveguide 9 is as follows. It has a thickness of about the wavelength of semiconductor laser light (for example, about 0.8 μm), and separates the active layer 7 from the optical waveguide 9 .

According to the above configuration, the laser beam excited within the semiconductor laser chip 6 is repeatedly reflected at both end faces of the active layer 7, but at this time, the laser beam that has seeped into the cladding layer 12 is as thin as the wavelength. Therefore, the laser light propagates further to the optical waveguide 9 below, and as a result, the laser light is transmitted from the semiconductor laser chip 6 to the optical wavelength conversion element 8.

As described above, according to this embodiment, the semiconductor laser chip 6
By providing the cladding layer 12 with a thickness equal to or less than the wavelength and in contact with the optical wavelength conversion element 8, laser light is transmitted from the semiconductor laser chip 6 to the optical wavelength conversion element 8.

Effects of the Invention As described above, the present invention provides an optical wavelength conversion device comprising a semiconductor laser and an optical waveguide having an optical wavelength conversion function based on a nonlinear optical effect. By butting the active layer end face of the semiconductor laser or the optical waveguide end face across a gap, an optical system such as a lens is inserted from the semiconductor laser chip to the optical wavelength conversion element while protecting the active layer end face and the optical waveguide end face. Laser light can be directly optically coupled without any interference.

In addition, by arranging the active layer of the semiconductor laser and the optical waveguide in parallel with a gap equal to or smaller than the wavelength, laser light can be transmitted from the semiconductor laser chip to the optical wavelength conversion element without intervening optical systems such as lenses. can be set.

[Brief explanation of drawings]

1 and 2 are front views and exploded perspective views of an optical wavelength conversion device according to a first embodiment of the present invention, and FIGS. 3 and 4 are front views of an optical wavelength conversion device according to a second embodiment of the present invention. The figure and an enlarged front view of main parts, and FIG. 5 are configuration diagrams of a conventional optical wavelength conversion device. 6...Semiconductor laser chip, 7...11 active layers, 8...Optical wavelength conversion element, 9...
・Optical waveguide, 10... Gap, 11.12...
...Clad layer.

Claims (2)

[Claims] (1) In an optical wavelength conversion device comprising a semiconductor laser and an optical waveguide having an optical wavelength conversion function based on a nonlinear optical effect, the semiconductor laser An optical wavelength conversion device characterized in that an end face of the active layer and an end face of the optical waveguide are brought into contact with each other. (2) In an optical wavelength conversion device consisting of a semiconductor laser and an optical waveguide having an optical wavelength conversion function based on a nonlinear optical effect, the active layer of the semiconductor laser and the optical waveguide are arranged in parallel with a gap of less than the wavelength. An optical wavelength conversion device characterized by: