WO2007117000A1

WO2007117000A1 - Semiconductor laser module for excitation

Info

Publication number: WO2007117000A1
Application number: PCT/JP2007/057843
Authority: WO
Inventors: Shigeki Sakaguchi
Original assignee: Central Glass Company, Limited
Priority date: 2006-04-12
Filing date: 2007-04-09
Publication date: 2007-10-18
Also published as: JP2007287727A

Abstract

Disclosed is a semiconductor laser module for excitation, which is characterized in that at least a photocatalyst body having a photocatalytic activity and a phosphor which absorbs a laser light and generates an excitation light for activating the photocatalyst body are arranged in a package.

Description

Specification

Semiconductor laser module for excitation technology

The present invention relates to a laser package in a pumping semiconductor laser module that has high output and high reliability used in an optical amplifier.

Background of the Invention

In optically pumped optical amplifiers such as optical fiber amplifiers and fiber lasers, semiconductor lasers are often used as pumping light sources. In particular, Er-doped fiber amplifiers (EDFAs), which are indispensable devices for optical network construction, use semiconductor lasers with wavelengths of 980 and 1480 nm as pumping light sources. EDFAs tend to increase in output with the evolution of optical networks and circuits. For this reason, pumping semiconductor lasers have also increased in output, especially in the 980 nm band.

[0003] The EDF A excitation laser used in the optical network is generally a single-mode laser, but the energy density increases as the laser output increases. Opportunities also increase. Optical damage may occur due to adhesion of impurities on the laser chip emission surface. In the laser package, since such impurities are known to be organic substances, the inside of the laser package is sealed with a dry inert gas containing a small amount of oxygen in order to prevent the deposition of impurities. A technique for stopping is disclosed (see Patent Document 1).

[0004] In the present technology, an organic substance is oxidized with oxygen and decomposed into moisture and carbon dioxide gas, and the generated gas component is adsorbed by an adsorbent disposed in a package. In this way, organic impurities can be oxidized with oxygen to prevent the impurities from adhering to the laser light emitting surface.

Patent Document 1: Japanese Patent No. 3452214

Summary of the Invention

[0005] The method described in, for example, Japanese Patent No. 3452214 described above is certainly organic. Although pure products can be decomposed, on the other hand, the presence of oxygen causes the laser chip to be adversely affected by oxidation and so on. Therefore, in order to exhibit such a function while preventing the adverse effects of oxygen, it is necessary to strictly control the oxygen concentration in the sealing gas component.

[0006] In addition, since moisture adversely affects the circuit for driving the laser chip, it is necessary to enclose the laser package with a dry gas. However, even if it is sealed with a dry gas, the moisture in the sealing gas cannot be completely removed, and a trace amount of moisture is contained. In addition, since the knocking material isotropic force also generates hydrogen, if oxygen is contained in the sealing gas, moisture is generated in response. In order to prevent the generation of hydrogen, it was necessary to heat the package itself at a high temperature for a long time to perform dehydrogenation treatment.

As described above, in the conventional technology, the oxygen is added to the sealing gas of the laser package while excluding moisture, while the reaction between oxygen and organic impurities and the package material force are released hydrogen and Moisture is inevitably generated by this reaction. In order to simultaneously remove the adverse effects on the chip and the like due to the presence of oxygen, the removal of organic impurities, and the removal of moisture at the same time, it was necessary to strictly control the component of the package sealing gas. Therefore, there is a problem that the package sealing process becomes complicated.

[0008] According to the present invention, at least a photocatalyst having a photocatalytic action and a phosphor that generates excitation light that absorbs laser light and activates the photocatalyst are incorporated in the package. An excitation semiconductor laser module is provided. This semiconductor laser module is different from the conventional technology in which oxygen is contained in the sealed gas in the package.

Brief Description of Drawings

FIG. 1 is a diagram showing an example of an embodiment of the present invention.

Detailed description

[0010] The present invention can be used not only for communication systems in the field of optical communication but also for application fields of optical transmission such as evaluation and measurement.

According to the present invention, a semiconductor pumping array used for an optical fiber amplifier or an optical fiber laser is used.

In addition, a trace amount of moisture and organic impurities contained in the sealing gas inside the package can be removed, which prevents failures such as optical damage of the laser chip. Therefore, it is possible to manufacture a semiconductor laser module for excitation with high output and high reliability.

FIG. 1 shows an example of an embodiment of the present invention. The laser chip 1 emits laser light from the emission surface when an electric current is supplied from the outside. The laser light is coupled to the output fiber 3 by an optical coupling means such as a lens and is output to the outside. At this time, a part of the laser beam is not necessarily output to the outside (usually about 30%) is scattered inside the package 2.

The light scattered inside the package 2 is absorbed by the phosphor 5, and the phosphor 5 generates fluorescence having a wavelength that activates a photocatalyst different from the laser light wavelength. The generated fluorescence is absorbed by the photocatalyst 4, and organic impurities present in a trace amount in the package sealing gas are decomposed by the photocatalytic reaction. The reaction product is adsorbed by the adsorbent and removed from the sealing gas.

Example 1

Hereinafter, the present invention will be described with reference to examples. However, the present invention is not limited to the examples.

[0015] Based on FIG. Laser chip 1 was a GaAs laser chip with an oscillation wavelength of 980 nm. The phosphor 5, using Yb (Itsuterubiu beam) and Tm (thulium) trace (total of about 0.8 wt ^_0/0) the added yttrium oxide-based ceramics are infrared visible conversion phosphor. For the photocatalyst 4, a WO—TiO-based catalyst that can generate a catalytic function even by irradiation with visible light was used. The concentration of WO was about 3% by weight. Phosphor and light

3 2 3

The catalyst body was in the shape of a chip having a size of about 3 mm square and a thickness of about 0.5 mm. The knocker was a mini-DIL type, and the chip-like photocatalyst and phosphor were fixed inside the package lid with an inorganic adhesive. After the laser chip assembly was accommodated inside the package, the lid was fixed to the package body by welding.

[0016] The laser light of 980 nm scattered inside the package is absorbed by a coordinated multiphoton absorption process by Yb and Tm ions contained in the phosphor, and the phosphor generates fluorescence around 470 nm. Since photocatalyst 4 contains a WO component, it is around 500 nm.

Three

In this wavelength range, the photocatalytic function is exhibited. The catalyst function is expressed by the following reaction. [0017] TiO + hv → TiO * (e— + h +)

twenty two

WO + xe— + xH + → H WO

3 x 3

2H 0 + 4h ⁺ → O + 4H +

twenty two

[0018] By the above reaction, moisture contained in the sealing gas inside the package is decomposed to generate oxygen. Due to the generated oxygen, a trace amount of organic impurities contained in the sealing gas is decomposed into oxygen and becomes moisture and carbon dioxide. That is, even if a dry gas containing no oxygen is used as the sealing gas, there is an advantage that a trace amount of remaining water can be removed and at the same time organic impurities can be removed.

[0019] The mini-DIL type laser module manufactured as described above was kept in a thermostatic chamber set at a temperature of 70 ° C and continuously operated by supplying current so that the fiber output became 200 mW. Even after 5000 hours, the output remained within 1% of the fluctuation, and no reduction in output was observed. As a result, a semiconductor laser module for excitation having high output and high reliability was obtained by using the present invention.

[0020] As described above, it is not necessary to contain oxygen in the sealing gas. Therefore, strict control of the components is not necessary, and a very small amount of water and oxygen contained in the sealing gas is generated. There is an advantage that moisture and organic impurities contained in the sealing gas can be removed simultaneously. Hydrogen and carbon dioxide gas can be removed from the sealing gas by adsorbing them by installing an adsorbent as necessary. Further, in this embodiment, the force using Yb and Tm-added ceramics as the phosphor is not limited to this, and any composition that emits light that activates the photocatalyst can be used.

Example 2

[0021] An example using an infrared photostimulable phosphor as a phosphor will be described below. Infrared photostimulable phosphor is Ca S (calcium sulphate) with Eu (Yuguchi Pium), Sm (Samarium), Nd (Neodymium) added in small amounts (total 1.2% by weight). Was used. The size was about 3 mm square and the thickness was about 0.5 mm, and it was fixed to the back of the knocker lid. A mini-DIL type laser module was produced in the same manner as in Example 1 except that the infrared photostimulable phosphor was irradiated with ultraviolet rays prior to welding the lid to the package body.

[0022] The laser module was tested in the same manner as in Example 1. Shown to work stably

Claims

The scope of the claims

[1] Excitation characterized in that at least a photocatalyst having a photocatalytic action and a phosphor generating excitation light that absorbs laser light and activates the photocatalyst are contained in the package! Semiconductor laser module.

[2] The semiconductor laser module for excitation according to claim 1, wherein the phosphor is an infrared-visible conversion phosphor or an infrared photostimulable phosphor.

[3] The photocatalyst is a TiO photocatalyst containing at least WO as a component.

3 2

The pumping semiconductor laser module according to claim 1 or 2.