JPH09295355A - End face lens of micro optical element and method for forming end face lens of micro optical element - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To improve the coupling efficiency in a coupling portion for coupling the light emitted from the end portion of a micro optical element with another optical component to effectively couple the emitted light and eliminate the difference in the coupling efficiency. Provided is an end lens capable of increasing the tolerance and a method for forming the end lens. An end surface 1a of a laser light emitting side of an optical element 1 is provided.
In the above, the optical lens structure 5 is formed by solidifying the fluid substance thin film 5a which is raised in the central portion by the fluid substance 7 dropped or attached.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a semiconductor laser device,
An end face lens of a micro optical element suitable for application to a micro optical element such as an optical switch or a planar optical circuit element that needs to effectively couple light propagating in a waveguide with another optical element, and a method for forming the same. Regarding

[0002]

2. Description of the Related Art Normally, the light emitted from or incident on an end surface of an optical element is condensed by a lens or the like and coupled with other optical components such as an optical fiber. At this time, a part of the light is coupled to the waveguide through the end face of the optical element.

For example, as shown in FIGS. 9 and 10, the light b1 emitted from the end face of the active layer a1 of a semiconductor laser device a, which is an example of an optical device, is transformed into a deformed lens c (in the case of the single device of FIG. 9), or The spherical lens d, the Selfoc lens e (the array-like element in FIG. 10), and the like collect light b2 and make it enter the waveguide formed of the optical fiber f which is another optical component.

[0004]

However, the intensity distribution of the light emitted from the optical element a exhibits a Gaussian distribution, and the emitted light spreads as indicated by the symbol b1. Therefore, the central portion of the Gaussian distribution ( Only the strong part) can be bonded. Conversely, the light at both ends of the Gaussian distribution cannot be combined sufficiently. Therefore, since there is light that cannot be coupled, there has been a problem in the past that coupling efficiency is limited. Further, if the lenses are not brought close enough to each other when they are combined, the difference in the coupling efficiency depending on the position of the lenses is considerably large (the tolerance is small). Therefore, conventionally, there is also a problem in that the position of the joint portion is restricted and a free design cannot be performed.

The present invention has been made to solve the above-mentioned conventional problems, and improves the coupling efficiency at the coupling portion for coupling the light emitted from the end portion of the minute optical element with other optical components. An object of the present invention is to provide an end face lens of a micro optical element that can effectively couple incident light and can increase the tolerance by eliminating the difference in coupling efficiency and a method for forming the same.

[0006]

The present invention has the following constitution in order to solve the above problems. According to a first aspect of the present invention, in an optical coupling portion in which light emitted from an end surface of a micro optical element that propagates light in a waveguide is combined with another optical component, the light is dropped or attached to the end surface of the optical element. An end surface lens of a micro optical element, characterized in that an optical lens structure is formed by solidifying a fluid substance thin film in the central portion which is raised by the fluid substance.

According to a second aspect of the present invention, optical element materials are arranged in an array at an optical coupling portion where light emitted from an end face of a micro optical element for propagating light in a waveguide is coupled with other optical components. A groove for regulating the flow of the fluid substance is formed between the adjacent element emission parts on the surface where the emission light side end surfaces of the respective elements are arranged, and the fluidity is provided on the end surface of the optical element. An end face of a micro optical element characterized in that a substance is dropped or adhered to form a thin film of a fluid substance having a raised central portion by its surface tension, and the thin film is solidified to form an optical lens structure on the end face. This is a lens forming method.

The inventor has conducted various researches and developments in order to improve the optical coupling efficiency and the degree of design freedom in the optical coupling portion between the micro optical element and other optical components. as a result,
A fluid substance such as a sol is dropped or attached to the end face of a micro optical element such as a semiconductor laser, so that the central portion is raised due to the surface tension of the fluid substance itself, and the outer shell of the end face becomes thin, It becomes a lens shape. Then, the present invention has been made paying attention to the fact that an optical lens structure can be formed by solidifying the lens-shaped fluid substance.

According to the present invention, the light emitted from the end face of the optical element is converged by the lens in which the fluid thin film is solidified and the divergence angle is reduced. Therefore, as compared with the conventional one in which a lens made of a fluid substance thin film is not formed, the emitted light is converged more than the Gaussian distribution, and the coupling efficiency with other optical components is improved. Further, since it is not necessary to bring the lenses close to each other, the difference in the coupling efficiency depending on the position of the lens becomes small (the tolerance becomes large).

Further, according to a second aspect of the present invention, an array of optical elements or an optical element material before being divided into individual optical elements are arranged in an array, and the end surface on the outgoing light side of each element is arranged. A groove for restricting the flow of the fluid substance material is formed between adjacent element emission parts, so that the dropped or adhered fluid substance is partitioned by each groove by this groove. The fluid substance thin film made of does not become integrated at the end faces adjacent to each other, and can be surely formed in a swelled one in the central part due to the surface tension of each end face of each element.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 and 2 are explanatory views of an end face lens by a lens structure 5 of a semiconductor laser device (an example of a micro optical device 1) according to an embodiment, FIG. 1 shows a single semiconductor laser device, and FIG. An explanatory view of a semiconductor laser device before being made into a chip or in an array is shown.

The semiconductor laser device, which is the optical device 1, generates and propagates laser light in an active layer (corresponding to a waveguide) 3 sandwiched by clad layers, and has an end face 1a of the device 1. The light emitted from is coupled to an optical fiber (an example of another optical component) 4 described later. Incidentally, in the figure, the cladding layers on both sides of the active layer 3 of the semiconductor laser device, the substrate of the outer layers thereof, and the like are well known and are not shown.

End facet 1 of laser beam emitting side of the optical element 1
In a, a fluid substance material is dropped or adhered to form an optical lens structure 5 in which the fluid substance thin film in a raised state in the central portion is solidified.

As the fluid material for forming the optical lens structure 5, various materials can be used as long as they are fluid until they are dropped or attached and are light transmissive materials that are solidified under a certain condition thereafter. The material can be selected and used. Preferably, a ceramic such as SiO ₂ , Al ₂ O ₃ or TiO ₂ by a sol-gel method, a thermosetting or light (ultraviolet) curable resin (organic compound) polyimide, PMMA (polymethylmetaacrylate), etc. Can use silicone (RTV: room temperature curing type etc.).

The optical element 1 is, in an example of a semiconductor laser element, length × width × height of 300 (μm) × 100 (μm) × 20.
It can be made very small with a size of 0 to 1000 (μm).

Next, a method of manufacturing the lens structure 5 will be described with reference to FIGS.
A description will be given based on FIG. As one of methods for forming the fluid substance thin film 5a on the emission side end face 1a of the optical element 1 such as a semiconductor laser device by the fluid substance material 7, an example of a method of dropping the fluid substance material 7 will be described. . In this example, as shown in FIG. 3, the fluid substance material 7 is injected into a well-known microdispenser 6, and the microdispenser 6 is singulated (shown in FIG. 3A) or formed into chips from the dropping side end portion thereof. Front or array (shown in Figure 3 (b))
The fluid material 7 is dropped and applied to the end surface 1a of the optical element 1. At this time, the dropping amount is controlled so that the surface of the droplet rises due to the surface tension so that the fluid substance material 7 dropped at this time has the shape of the thin film 5a shown by the chain double-dashed line in FIG.

Further, as an example of a method of applying (adhering) the fluid substance material when forming the fluid substance thin film 5a, as shown in FIG. 4, the optical element 1 is fixed on the flat plate 8 in an appropriate amount, This flat plate 8 is fixed to at least a vertically movable stage (Z table using a step motor or encoder motor) 9. Then, the flat plate 8 on which the optical element 1 is fixed is lowered so that the end surface 1a of the optical element is just in contact with the liquid surface 7a of the fluid material 7 in the bath 10. As a result, the fluid substance material 7 is adhered and applied to the end surface 1a, and the thin film 5a made of the material 7 has a thick lens shape at the center due to the surface tension. The thin film 5a made of the fluid material 7 applied in this manner
Is cured to have the function of the lens structure 5.

Here, in the case where the optical elements 1 themselves or those arranged in an array before being divided as described above, the lens structure 5 must be formed for each waveguide,
As shown in FIG. 5, a groove 10 recessed with respect to the emission side end face 1 a is formed between the waveguides (active layers) 3 and 3 (middle). Therefore, since the fluid substance material 7 that has been dropped or attached is partitioned by the groove 10 for each of the elements 1 and 1, the thin film 5a made of the material 7 does not become integral at the adjacent end faces, and The element end faces 1a, 1a can be surely formed in a swelled one in the central portion due to the surface tension thereof.

Regarding the lens shape formed on the exit side end face 1a of the optical element 1, if the exit end of the waveguide is deviated from the center of the end face of the optical element 1, the lens shape is adapted to the exit end. Preferably. like this,
A case where a semiconductor laser device as an example of the optical device 1 is divided from a wafer will be described. That is, FIG. 6 (a)
When the active layer 3 is formed near the front surface side of the wafer 11 as seen in a plan view in FIG.
The grooves 10 are formed on both sides of the element by etching, and the elements 1 arranged in an array are cleaved (divided) from the dividing line 12. Then, as seen from the cleavage plane in FIG. 6B, the active layer 3 appears on the emission side end face 1a in a state of being biased to the surface side.
Then, when the fluid substance material 7 is dropped or attached to the end face, the fluid substance material 7 is attached to the active layer 3 in a large amount. For example, as shown in FIG. 6C, the raised portion can be brought closer to the active layer 3 side.

The fluid substance material thin film 5a formed as described above is solidified (gelled). As a result, the optical lens structure 5 can be formed on the exit-side end surface 1a of the optical element 1 without a gap. In this way, the end face 1 of the optical element 1 is formed by the lens structure 5 formed by solidifying the fluid substance thin film 5a.
The light emitted from a is converged and the spread angle is reduced.

Therefore, as shown in FIG. 7, the emitted light is converged more than the Gaussian distribution θ as compared with the conventional product in which the lens made of the fluid substance thin film is not formed, so that the coupling efficiency with other optical components is improved. improves. Further, since it is not necessary to bring the lenses close to each other, the difference in the coupling efficiency depending on the position of the lens becomes small (the tolerance becomes large).

FIG. 8 shows an optical coupling section in comparison with the conventional semiconductor laser array shown in FIG. As shown in FIG. 8, the emitted light 13 from the laser array 1 is converged by the lens structure 5 and is incident on the spherical lens 14 (and the cell hook lens 15) without leakage and is reliably coupled to the optical fiber 4 as a whole. it can.

Further, since the fluid thin film can be formed by a process of dropping or adhering the end face 1a on the emission side of the optical element 1 and only solidifying it, a separate optical lens is separately constructed and attached. It can be formed extremely easily compared to

The optical element is not limited to the semiconductor laser element, but can be applied to a minute optical element such as an optical switch or a planar optical circuit that emits light from the end face of the waveguide.

[0025]

As described above, according to the present invention, it is possible to improve the coupling efficiency in the coupling portion that couples the light emitted from the end portion of the micro optical element with other optical components and effectively couple the emitted light. Tolerance can be increased by eliminating the difference in coupling efficiency.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an end face lens formed of a lens structure of a semiconductor laser device (an example of a micro optical device) according to an embodiment, showing an example of a single semiconductor laser device, FIG. ) Is a front view.

FIG. 2 is an explanatory view of an optical element before being made into a chip or in an array form.

FIG. 3 is an explanatory view illustrating a method for manufacturing a lens structure,
(A) is an example of a single optical element, (b) is an example of an array of optical elements.

FIG. 4 is an explanatory diagram of another example of the method for manufacturing the lens structure.

FIG. 5 is an explanatory diagram of formation of grooves in an array-shaped lens structure.

6A and 6B are explanatory views of dropping or applying of the fluid substance material in FIG. 5, FIG. 6A is a plan view, FIG. 6B is a cleavage plane view, and FIG. 6C is a view showing dropping or application. is there.

FIG. 7 is a diagram illustrating an effect of the end surface lens of the present embodiment.

FIG. 8 shows an example of an optical coupling section of a semiconductor laser array.

FIG. 9 is an explanatory diagram showing an example of an optical coupling section of a conventional semiconductor laser.

FIG. 10 is an explanatory diagram showing another example of the optical coupling section.

[Explanation of symbols]

 1 Optical Element 3 Active Layer 5 Lens Structure 5a Fluid Material Thin Film 7 Fluid Material

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location B29K 101: 10

Claims (2)

[Claims] 1. An optical coupling part in which light emitted from an end face of a micro optical element for propagating light in a waveguide is coupled to another optical component, and a flow dropped or attached to the end face of the optical element. An end face lens of a micro optical element, characterized in that an optical lens structure is formed by solidifying a fluid substance thin film which is raised in the central part by a conductive substance. 2. An optical coupling material in which light emitted from an end face of a micro optical element for propagating light in a waveguide is coupled with another optical component, wherein optical element materials are arranged in an array. In the surface where the emitted light side end face of each element is arranged, a groove for restricting the flow of the fluid substance is formed between the adjacent element emission parts, and the fluid substance is dropped on the end face of the optical element, or A method for forming an end face lens of a micro optical element, which comprises depositing and forming a thin film of a fluent substance having a bulge in a central portion by the surface tension, and solidifying the thin film to form an optical lens structure on the end face.