JPS59119312A - Hybrid optical integrated device - Google Patents

Abstract

PURPOSE:To reduce the size of a device, to facilitate the assembling operation of elements, and to improve reliability by using a spherical lens which is obtained by forming a reflecting or translucent film on a plane running in the center as an optical circuit element. CONSTITUTION:The reflecting film 3 of the spherical lens 2b of a hybrid optical integrated device for, for example, four-wavelength multiplexing reflects light with wavelength lambda1 selectively, the reflecting film 3 of a spherical lens 2c reflects light with wavelength lambda2, and the reflecting film 3 of a spherical lens 2d reflects light with wavelength lambda3. Then, the light with wavelength lambda1 from a semiconductor laser element 5 is outputted through the spherical lenses 2b and 2a and multiplexed light of wavelengths lambda2-lambda4 admitted to the spherical lens 2a from the outside is passed through the spherical lens 2b and demultiplexed by the spherical lenses 2c and 2d respectively to be photodetected by photodetectors 7a-7c respectively. Consequently, the size of the device is reduced and the productivity and reliability are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hybrid optical integrated device that is miniaturized and has a structure that is easily hermetically sealed.

[Technical background of the invention and its problems]

Optical circuit elements such as demultiplexers and multiplexers for wavelength multi-wavelength optical transmission, as well as optical branching and merging elements used in optical networks that perform passive optical distribution, are information processing devices that effectively utilize optical fibers. This is very important in configuring a transmission system economically.

However, in the past, as an optical circuit element of this yuzu, for example, micro-optics using a focusing rod lens, heating processing of optical fiber into a tapered shape, -7,63=ka7.7
-2, 7th U. 7 (Fiberoptics is known.

However, although these optical circuit elements are called micro optical elements compared to conventional optical lens systems, grisms, etc., they have dimensions of about 5 mm for converging lenses and the like. It is approximately the same size as a VLSI chip for switching electronic circuit ICs.

For this reason, when an optical device (optical circuit) exhibiting functions such as demultiplexing, multiplexing, branching, and merging using such a microscopic optical element is constructed, its size becomes as large as about 2 to 3 Crn. Therefore, it has been extremely difficult to realize a hybrid optical integrated device by hermetically sealing the entire optical device in order to improve its reliability. Moreover, the assembly of such a hybrid optical integrated device is said to be entirely manual labor, and has the problem of extremely low productivity.

On the other hand, in recent years, optical fiber cables have been improved and their prices reduced, and the development of optical network systems to replace electrical systems using conventional coaxial cables is being actively promoted. Even taking these trends into consideration, the development of compact and highly reliable hybrid optical integrated devices has been attracting a great deal of attention.

[Purpose of the invention]

The present invention has been made in consideration of these circumstances, and its purpose is to improve productivity by simplifying the assembly work of elements, and also to reduce the size of the device. The object of the present invention is to provide a highly practical non-hybrid optical integrated device that can sufficiently improve reliability.

[Summary of the invention]

The present invention realizes a hybrid optical integrated device that exhibits a desired optical function by using a spherical lens, which has a reflective film or semi-transparent film made of a dielectric multilayer film or the like on a plane passing through the center, as an optical circuit element. .

〔Effect of the invention〕

Therefore, according to the present invention, a minute optical circuit element with a built-in reflective film or semi-transparent film in a plane passing through the center of a spherical lens constituting a lens system is used, so that an optical device exhibiting a desired function can be made very easily. It can be assembled compactly and can be easily sealed. Moreover, the assembly work can be easily performed, and a highly reliable optical device can be realized with good productivity and at low cost. Furthermore, the numerical aperture of the optical system formed by the ball lens can be made sufficiently large, and great practical effects such as facilitating optical coupling with an optical fiber cable can be achieved.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an embodiment device. This device has 4
This hybrid optical integrated device for wavelength multiplexing includes a ball lens 2 (2a) on a silicon substrate 1.

2b to 2h) are integrated. For example, as shown in FIG. 2, the ball lens 2 has a reflective film or a semi-transparent film 3 made of a dielectric multilayer film, a metal film, etc. formed in a plane passing through its center.

In this case, the semi-transparent film 3 is defined as the reflective film 3 in a broad sense, and the film that exhibits the functions of splitting, combining, splitting, and converging light will be described.

Therefore, the reflective film 3 provided on the equatorial plane, which is a plane that passes through the center of the spherical lens 3, reflects the light that passes through the spherical lens 2 and receives the lens action, as shown in FIG. 2(b) K. For example, it exhibits semi-transmissive and semi-reflective effects. This semi-transmission/semi-reflection is performed, for example, wavelength selectively.

Among these ball lenses 2, the ball lenses 2a, 2b, 2c, and 2d forming the main ball lens system are formed with, for example, rectangular holding holes 4m, 4b, which are drilled with high precision on the silicon substrate 1 by photolithography. 4c, 4d
mounted and fixed with adhesive. the ball lens 2a;
2b, 2c+2d are, for example, 500 μm in diameter 1 reflective film 3
The diameter is 250 μm, and the holding holes 4a to 4d for holding this are set to have openings of 310 μm and a depth of approximately 70 μm.

The ball lens 2a is positioned so that its reflective film reflects input and output light from above toward the ball lens 2b,
Moreover, the ball lens 2b + 2c r2d has its reflective film 3
are positioned so as to horizontally reflect the light passing through the main spherical lens system.

The reflective film 3 provided on the ball lens 2b reflects only the light of wavelength λl, and in the lateral direction of the ball lens>b is a surface-emitting semiconductor laser element 5 that outputs laser light of wavelength λ1. It is provided. This semiconductor laser element 5 modulates an oscillated laser beam under the control of a drive circuit 6 integrated on the substrate 1. The laser beam is reflected by a ball lens 2e provided on the element 5. reflected through the membrane 3,
It is introduced into the ball lens 2b. Oka, this ball lens 2e
For example, the size is about 300 μm in diameter, and the other @ spherical lenses 2f and 2g.

2h is similarly configured. As a result, the laser beam of wavelength λl from the semiconductor laser element 5 is sent out from the ball lens 2b via the ball lens 2a.

Further, photodetectors 7a and 7b are provided in the lateral direction of the ball lenses 2c and 2d, respectively, and a photodetector 7c is provided on the end side of the ball lens 2d. These 7 Oto detectors 7a.

7b and 7c are ball lenses 2f provided thereon.

2g and 2h, the light branched by the ball lenses 2c and 2d, each of which has the same wavelengths λ2, λ3, and λ4, is received, and the received light signals are integrated on the substrate 1. They are detected by detection circuits 8a+8b and 8c, respectively. In other words, the reflective film 3 of the spherical lens 2b receives light with a wavelength λ1, the reflective film 3 of the spherical lens 2C receives light with a wavelength λ2, and the reflective film 3 of the spherical lens 2d receives light with a wavelength λ3.
It is designed to selectively reflect the light of each wavelength. The light of wavelength λ] from the semiconductor laser element 5 is outputted from the ball lens 2b via the ball lens 2a, and the light of wavelength λ2, λ3 introduced into the ball lens 2a from the outside.
, λ4 passes through a ball lens 2b, is demultiplexed by ball lenses 2c and 2d, and is received and detected by photodetectors 7a, 7b, and 7c, respectively.

This device exhibiting such a function uses ball lenses 2a and 2b.
, 2c, 2d, and other conditions, 3.
Hybrid integration can be achieved with the size of five cabinets. Moreover, the spherical lens 2a l that constitutes the main spherical lens system
2b l 2c + 2d itself has a reflective film 3 on its equatorial plane and exhibits a demultiplexing/combining effect, so its optical system becomes extremely simple, realizing complex optical circuit functions with a small number of parts. be able to. In addition, the numerical aperture of the optical system can be increased due to the spherical lens action,
Facilitates optical coupling with optical fibers. In addition, since this device is small as mentioned above, it is easy to keep it airtight (the g-axis property can be sufficiently improved, and the device can be manufactured by effectively utilizing electric circuit integration technology). It has great practical effects, such as being able to.

By the way, the above-mentioned ball lens 2 having the reflective film 3 provided on the equatorial plane is manufactured, for example, as follows. FIG. 3 shows an example of this. First, two lens media 11.1
Prepare 2. Then, a dielectric multilayer film 13 that functions as a desired optical circuit element is formed on one surface of one lens medium 11. Then, this dielectric multilayer film 13 is patterned using a lithography technique or the like to form each reflective film 3f of a predetermined size. And lens medium t-1
The other lens medium 12 is bonded to the surface on which the reflective film 3 is formed, with the reflective film 9 in between, to form a block body 14.

This block body 14 is diced along the broken line in the figure to obtain a plurality of key-vic bodies 15 with the reflective film 3 at the center. These cubic bodies 15
The zero dimension is made slightly larger than the desired diameter of the ball lens. Thereafter, these cubic bodies 15 are put into a rotating polishing drum and rotary polished to obtain a spherical lens 2 as a sphere. Similarly, this rotating polishing drum is used for manufacturing ball bearings, etc., and as a result, extremely high dimensional accuracy can be obtained. Therefore, the small radius of curvature,
Furthermore, it becomes possible to form a ball lens 2 that can form a focusing optical system with a large difference in refractive index. However, this ball lens 2
In order to position the reflective film 3 on the equatorial plane of the plane, it is necessary to correctly determine the dimensions of each part of the Ki-Vic body 15.

To make the ball lens 2, for example, a dielectric multilayer film is formed on the cut surface of a lens medium rod that is cut in half, and then this is recombined, and this rod is cut to obtain a chip that becomes the base of the ball lens. , this chip may be manufactured by machining it into a spherical surface.

In this way, it is possible to obtain a ball lens 2 of microscopic size with a reflective film 3 on the equatorial plane, and to easily assemble this on the substrate 1 to realize a hybrid optical integrated device. In other words, it is extremely difficult to miniaturize a conventional rectangular parallelepiped optical member on which a reflective film is formed.

Moreover, when assembling these with dimensions on the order of several hundred micrometers, it is difficult to use the surface of the rectangular parallelepiped as a reference surface for angle adjustment, and it is likely to cause deviation with respect to the oblique incident optical axis. In this regard, in the ball lens according to this device, since the reflective film 3 exists on a plane including the center, there is no beam deviation, and even if it is miniaturized, the film conditions are such that it can maintain its high-precision function. can be maintained. In history, functions such as demultiplexing and multiplexing while shouldering optical lens system functions? :! A, the dimensions of the device component parts can be easily unified, and the assembly process can be simplified.

Further, the angle of each ball lens 20 can be adjusted using a light beam, and highly accurate positioning can be performed only by rotating the ball lens 2.

Furthermore, as shown in the embodiment, the ball lens 2 can be optically arranged in a plane on a substrate such as silicon to realize the desired circuit function, which is extremely efficient in terms of productivity. I can say that there is.

As described above, according to the present device, it is possible to very effectively satisfy the various demands that have been desired in the past, and to provide an ultra-small and highly reliable hybrid optical integrated device.

By the way, when the radius of the spherical lens 2 is R1 and its refractive index is n, the focal length f of the spherical lens 2 is expressed as follows.

f=□・R...(1) 2(n-1) The main Gaussian surface passes through the center of the sphere as shown in FIG. (dH=R) On the other hand, when the unique spot size of the optical beam waveguide and the ωo1 confocal parameter are set to b, the following relationship holds true.

However, λ is the wavelength of light. It is known that the safe area of the light beam in this case is 0(d("4f...(3)). Also, d is the center-to-center distance between the two spherical lenses. A lens system with d=4f is called a concentric system, and a lens system with d=2f is called a confocal system. .

However, if the above concentric lens system is realized using the spherical lens 2, the light guided by this system will become a parallel beam in the paraxial ray region within the spherical lens, as shown in Figure 5. Become. Therefore, the above-mentioned light is reflected by the reflective film 3 provided on the equatorial plane of the above-mentioned ball lens 2. Demultiplexing/combining/
Very convenient when dividing or merging streams. However, the numerical aperture is, for example, refractive index n=1.447, wavelength λ-1
, 3μm, NA-0.07, angle approximately ±
There is a problem that the angle is small at 4°. Moreover, the spherical lens is d=
4f, and it is necessary to slightly modify the above-mentioned distance d when taking into consideration errors in the dimensions of the ball lens and the mounting position. If the lock is d) 4f, beam divergence will occur even if the number of ball lenses is five, so the above correction is usually performed as (d=4 f-ε). Therefore, although ideally such a concentric system could be formed to realize the hybrid optical integrated device, it is actually preferable to form a confocal system as shown below. .

That is, when a confocal lens system is constructed using a spherical lens, the light beam is stable in the paraxial ray region in the range of d=2f±ε, as shown in FIG. Divergent beams and convergent beams are alternately generated between each spherical lens. Therefore, in this case, it is necessary to devise a way to couple the above-mentioned alternately occurring diverging beams and converging beams with the light source and the photodetector, but this is relatively easy to realize. Moreover, the numerical aperture NA of such a confocal lens system is as large as 0.25 or more, and optical coupling with an optical fiber having a numerical aperture NA of about 0.2 can be easily performed. Furthermore, the length of the lens system can be reduced to approximately half that of the concentric system described above, thereby making it more compact. Also, the distance d between the spherical lenses is (
Since an error of about ε(0,05·R) can be tolerated, beam shape deviation does not pose a major problem.

Therefore, considering the following two points, it is possible to construct a confocal lens system using FM number of ball lenses 2 as shown in FIG. Multiplexing, demultiplexing, merging, branching, etc. of the light beams may be performed by using the optical system.

In addition, in FIG. 7, 2111-j is a semiconductor laser element with a wavelength λl, 22 is a semiconductor laser element with a wavelength λ4, 23°24,
'25 indicates light-receiving elements provided on each side of the rectangular parallelepiped block. Then, -E is detected by the light receiving element 23.
The light having the wavelength λ1 is monitored, and the light receiving elements 24 and 25
The lights with wavelengths λ2 and λ3 are detected with a deviation.

The device board on which these optical circuit elements are integrated is mounted in the same JfA package 26 as the semiconductor IC chip as shown in FIG. The optical connector 27 is configured to be connected to an optical fiber cable via an optical connector 27.

As described above, the present invention can realize a hybrid optical integrated device that performs the required functions with a very compact shape, and has great practical effects.

However, the present invention is not limited to the above embodiments. For example, the number of ball lenses to be incorporated into the device, the functions of their reflective films, etc. can be determined depending on the specifications. Although a diffraction grating or the like can be considered as a device for single-wave splitting or multiplexing, it can be said that it is more advantageous to use a multilayer film of the current-visitor body in view of dimensional constraints. In short, the present invention can be implemented with various modifications without departing from the gist thereof, and its application technology range is extremely wide.

[Brief explanation of the drawing]

FIG. 1 is a plan configuration diagram of an embodiment of the device of the present invention, and FIG. 2 (
a) and (b) are diagrams showing the configuration of the ball lens, Figure 3 is a diagram showing the manufacturing process of the ball lens, and Figures 4 to 6 are diagrams each showing the optical system constituted by the ball lens. FIG. 7 is a block diagram of the main parts of the present device which constitutes a confocal lens system, and FIG. 8 is an external view of the present device. 2 (2m, 2b to 2h)... Ball lens, 3... Reflective film (including semi-transparent film), 5... Semiconductor laser element, 7
a, 7b, 7c... optical detectors.

Claims (2)

[Claims] (1) A no-brid optical integrated device characterized in that a ball lens formed by forming a reflective film or a semi-transparent film on a plane passing through the center is used as the optical circuit element 7. (2) The hybrid optical integrated device 0 according to claim 1, wherein the reflective film or the semi-transparent film is made of a dielectric multilayer film.