JP2005037730A - Optical oscillation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical oscillation device using low-cost members, in which the number of alignment processes is reduced. <P>SOLUTION: The optical oscillation device has; an optical semiconductor element 1; a first lens 2 for collimating an oscillated laser light; a non-reciprocal optical element 3 on which the laser light transmitted through the first lens 2 is incident; a second lens 4 for concentrating the laser light transmitted through the non-reciprocal optical element 3 to an optical fiber 5; and a tilting table 11 in which a groove for guiding fixing positions of the first lens 2 and the second lens 4 is formed. In the optical oscillation device, the groove extents to the direction of the optical axis 6 of the laser light, and is inclined with respect to the direction of the optical axis 6, in a plane containing the optical axis 6 and the groove. A groove forming surface 15 is inclined in the extending direction of the groove, with respect to the facing bottom surface 16. The bottom surface 16 of the table is formed parallel to the optical axis. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical oscillation device mainly used in a high-speed and large-capacity optical communication system, and more particularly to an optical oscillation device suitable as a light source for a metro access network.

  An optical oscillation device used for high-speed and large-capacity optical communication has, for example, an optical configuration as shown in FIG. That is, the optical semiconductor element 1 that is a laser oscillation element, the first lens 2 that collimates the laser light, the nonreciprocal light element 3 such as an optical isolator, and the second lens 4 that is focused on the optical fiber. It is arranged along the axis 6. Such a laser oscillation device is called an LD (laser diode), an LD module, a semiconductor laser module, or simply an optical oscillation device.

  The reason why the light beam 7 is collimated by the first lens 2 in the LD is to efficiently transmit the laser beam to the nonreciprocal light element 3 such as an optical isolator. The nonreciprocal light element 3 such as the optical isolator By blocking the light, the stability of the signal of the oscillating optical semiconductor element 1 is ensured.

  Since the condensing angle for condensing on the core of the optical fiber 5 depends on the core diameter and refractive index of the optical fiber, and the spread angle of the laser light oscillated in the optical semiconductor element 1 depends on the size of the light emission spot. The first lens 2 and the second lens 4 must have different condensing distances. This means that a normal spherical lens having a different diameter must be used.

  Conventionally, as schematically shown in FIG. 3, the height of each component is adjusted by the bases 8 and 9 on the base material 10 in consideration of the difference in the size of the lens. However, when this method is used, optical path alignment of the optical system in consideration of the difference in height between the pedestals 8 and 9 has to be performed, which not only makes alignment difficult, but also reduces productivity.

  Patent Document 1 discloses an example of an optical module in which two spherical lenses are arranged on the same substrate. However, this technique is based on the accuracy obtained when anisotropic etching is performed using a semiconductor material such as Si or InP as a substrate, and it is not easy to obtain the accuracy by machining. In addition, in the production method using anisotropic etching, it is not easy to reduce costs unless the production quantity is more than a certain value.

  Further, in order to align the respective parts on the same axis of the optical system, a method is generally used in which a cylindrical lens is used and the shapes of the first lens and the second lens are arranged with at least the outer diameters aligned. However, this lens is very expensive, which increases the production cost of the entire optical component. In addition, such a cylindrical lens has a limitation in manufacturing characteristics, and the characteristics of the laser oscillation device are limited.

JP 2002-341189 A

  In light of these conventional problems, it is desirable to realize an optical oscillation device that uses a low-cost spherical lens and that uses a support structure for an optical component that can be easily aligned.

  That is, an object of the present invention is to provide an optical oscillation device that uses a low-cost member and can reduce the number of alignment steps.

  The optical oscillation device of the present invention includes a laser oscillation element, a first lens that collimates the oscillated laser light, a nonreciprocal light element that receives laser light that has passed through the first lens, and the nonreciprocal light element. An optical oscillation device comprising: a second lens for condensing the laser light that has passed through the optical fiber; and a pedestal formed with a groove that guides a fixed position of the first lens and the second lens. The first and second lenses are spherical lenses, and the groove extends in the optical axis direction of the laser light and is inclined from the optical axis direction in a plane including the optical axis and the groove. And

  The surface on which the groove of the pedestal is formed may be inclined in the extending direction of the groove with respect to the opposing bottom surface.

  The bottom surface may be formed in parallel with the optical axis.

  The cross-sectional shape of the groove is preferably V-shaped.

  And the cross-sectional shape of the said groove | channel may be a rectangle.

  Since the optical oscillation device of the present invention uses a low-cost member and an optical system support structure that can be easily aligned, according to the present invention, it is possible to provide a low-cost and high-productivity optical oscillation device. I can do it.

  The best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a schematic view showing a light oscillation device of the present invention. In the present invention, the first lens 2 that collimates the laser light output from the optical semiconductor element 1 that is a laser oscillation element, and the second that condenses the laser light transmitted through the nonreciprocal light element 3 onto the optical fiber 5. A spherical lens is used as the lens 4. Since the maximum efficiency can be obtained by matching the optical axis 6 of the laser beam incident on the spherical lens with the center of the lens, the first lens 2 and the second lens 4 must be of the same size. The height of the fixed position is different.

  Therefore, in the present invention, an inclined pedestal 11 in which a groove extending in the direction of the optical axis 6 of the laser beam oscillated from the optical semiconductor element 1 is provided on the upper groove forming surface 15 is used. The groove is provided with an inclination that compensates for the deviation of the optical axis 6 from the center of the lens when the optical axis 6 is parallel and the first lens 2 and the second lens 4 are disposed in the groove. As a result, even when spherical lenses having different sizes are used, the optical axes can be aligned with the centers of the first lens 2 and the second lens 4 without tilting the optical axes. Further, the nonreciprocal light element 3 is disposed between the first lens 2 and the second lens 4 on the upper surface of the inclined pedestal 11, and the optical semiconductor element 1 is disposed on the optical semiconductor element fixing surface 17 on the extension line of the groove of the inclined pedestal 11. Place.

  The inclined pedestal 11 will be further described. First, the bottom surface 16 of the inclined pedestal 11 is leveled and this surface is used as a reference surface. Next, the height of the light emitting part of the optical semiconductor element 1 is determined so that the optical axis 6 has a predetermined height from the reference plane. Next, an inclination angle from the optical axis with respect to the groove is determined based on the diameters of the first lens 2 and the second lens 4 and the distance between the lenses. Further, based on the height of the optical axis of the two lenses, the height of the light emitting portion of the optical semiconductor element 1, and the distance from the optical semiconductor element 1 to the first lens 2, the cross-sectional shape of the groove and the end of the groove from the optical semiconductor The distance to element 1 is determined. Further, a fixed surface is provided on the upper surface of the inclined pedestal 11 so that the optical axis 6 coincides with the approximate center of the optical surface of the nonreciprocal light element 3. In this way, the optical semiconductor element 1, the first lens 2, the nonreciprocal light element 3, and the second lens 4 are integrated using the inclined pedestal 11. In addition, about the alignment of the optical fiber 5, the alignment mechanism by a well-known technique is used.

  Next, the first embodiment of the present invention will be described in more detail. The configuration of the optical oscillation device of the first embodiment is as shown in FIG. A Si substrate wafer was used for the inclined pedestal 11 serving as the base of the optical member. First, a part of one side of the Si substrate is polished at an angle of 5.03 deg (grain size # 6000), and a rectangular groove is formed with a depth of 0.5 mm by dicing. In order to remove the chipping generated at this time, the surface is further polished (# 6000) after cutting. Cutting is performed so that the width of the groove is 0.03 mm (± 0.005 mm).

  After that, a notch for fixing the nonreciprocal element is produced at a design nonreciprocal element position in a direction perpendicular to the groove with a width of 0.85 mm and a depth of 1 mm. In this way, the inclined pedestal 11 is produced. The inclination angle of the manufactured groove is obtained by theoretical calculation from the relationship between the size difference between the first lens 2 and the second lens 4 and the ideal position.

  Regarding the lens to be used, TaF3R0.3 (NA = 0.35) manufactured by HOYA Co., Ltd. is used for the first lens 2, and TaF3R1.0 (NA = 0.1) manufactured by HOYA Co., Ltd. is used for the second lens 4. However, each part should have a non-reflective coating.

  As the non-reciprocal light element, an element configured by sandwiching a GdBiIG garnet thick film manufactured by NEC Tokin Co., Ltd. with Cupo (registered trademark) manufactured by HOYA Co., Ltd. as a polarizer is used. At this time, a magnetized material having a square hysteresis characteristic, which is usually called a latching type, is used for the garnet thick film to be used, which eliminates the need for a magnet and can greatly contribute to miniaturization.

  After the optical semiconductor element 1 and the nonreciprocal light element 3 are fixed to the inclined pedestal 11, the first lens 2 and the second lens 4 are arranged, and alignment work is performed along the groove. For fixing, a UV curable adhesive is used and instant bonding is performed at an optimum position while monitoring the laser beam.

  The optical oscillation device thus fabricated has a characteristic comparable to that of a conventional cylindrical lens product of 0.27 dB except for AR coating reflection of each component, insertion loss of nonreciprocal light elements, and alignment error. It is done.

  A light oscillation device according to a second embodiment of the present invention will be described with reference to FIG. A Si substrate was used for the inclined pedestal 11 serving as a base. First, a part of one side of the Si substrate is polished at an angle of 5.03 deg (# 6000), and a V groove is formed with a depth of 0.4 mm by dicing. As a dicing blade for forming the V-groove, a resin bonding blade ground so as to have a V-shaped cross section is used. The V-shaped dimension depends on the size of the lens used. Further, in order to remove the chipping generated at this time, the surface is further polished (# 6000) after cutting. Cutting is performed so that the width of the groove is 0.03 mm (± 0.005 mm). Thereafter, a notch for fixing the nonreciprocal light element is formed at a design nonreciprocal element position in a direction orthogonal to the groove with a width of 0.85 mm and a depth of 1 mm. In this way, the inclined pedestal 11 is produced. The inclination angle of the manufactured groove is obtained by theoretical calculation from the relationship between the size difference between the first lens 2 and the second lens 4 and the ideal position.

  Regarding the lens to be used, TaF3R0.3 (NA = 0.35) manufactured by HOYA Co., Ltd. is used for the first lens 2, and TaF3R1.0 (NA = 0.1) manufactured by HOYA Co., Ltd. is used for the second lens 4. However, each part should have a non-reflective coating.

  The non-reciprocal light element 3 is formed by sandwiching a GdBiIG garnet thick film manufactured by NEC TOKIN Co., Ltd. with a cupo (registered trademark) manufactured by HOYA Co., Ltd. as a polarizer. At this time, a magnetized material having a square hysteresis characteristic, which is usually called a latching type, is used for the garnet thick film to be used, which eliminates the need for a magnet and can greatly contribute to miniaturization.

  After the optical semiconductor element 1 and the nonreciprocal light element 3 are fixed to the inclined pedestal 11, the first lens 2 and the second lens 4 are arranged, and alignment work is performed along the groove. For fixing, a UV curable adhesive is used and instant bonding is performed at an optimum position while monitoring the laser beam. The optical oscillation device manufactured in this way has a characteristic comparable to that of a conventional cylindrical lens product of 0.27 dB except for AR coating reflection of each component, insertion loss of nonreciprocal light element, and alignment error. .

  In the above embodiment, an inclined pedestal with a groove formed on the upper surface is used, but a groove is formed on the upper surface of a parallel plate pedestal, and this pedestal is placed on a wedge-shaped plate and used in an inclined manner. May be.

  From the above results, the optical oscillation device of the present invention has no problem in characteristics and can be manufactured by simple alignment with a simple optical system. Therefore, according to the present invention, it is possible to provide an optical oscillation device that is inexpensive and has high productivity.

The schematic diagram which shows the optical oscillation apparatus of this invention. The optical block diagram of an optical oscillation apparatus. The schematic diagram which shows the conventional optical oscillation apparatus.

Explanation of symbols

1 optical semiconductor element 2 first lens
3 Non-reciprocal light element 4 Second lens
5 Optical fiber 6 Optical axis 7 Luminous flux 8, 9 Base 10 Base material 11 Inclined base 15 Groove forming surface 16 Bottom surface 17 Optical semiconductor element fixing surface

Claims (5)

  A laser oscillation element; a first lens that collimates the oscillated laser light; a nonreciprocal light element that receives the laser light that has passed through the first lens; and a laser beam that has passed through the nonreciprocal light element as an optical fiber. A light oscillation device comprising: a second lens for condensing light; and a pedestal on which a groove for guiding the fixed position of the first lens and the second lens is formed. The first and second lenses are spherical lenses. The groove extends in the optical axis direction of the laser beam and is inclined from the optical axis direction in a plane including the optical axis and the groove.   2. The optical oscillation device according to claim 1, wherein a surface of the pedestal on which the groove is formed is inclined with respect to an opposing bottom surface in an extending direction of the groove.   The optical oscillation device according to claim 1, wherein the bottom surface is formed in parallel with the optical axis.   4. The optical oscillation device according to claim 1, wherein a cross-sectional shape of the groove is V-shaped.   4. The optical oscillation device according to claim 1, wherein the groove has a rectangular cross-sectional shape.

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