CN-113720581-B - Optical probe, method for manufacturing the same, optical probe array, and optical probe card

CN113720581BCN 113720581 BCN113720581 BCN 113720581BCN-113720581-B

Abstract

Provided are an optical probe, an optical probe array, an optical probe card, and a method for manufacturing an optical probe, each of which has a single transmission mode and can efficiently measure an optical device. The optical probe (10) is provided with a first region (11) and a second region (12) which are connected in such a manner that optical waveguides having a single transmission mode are continuous. A first region (11) continuous to a tip surface (100) opposite to an optical device (20) includes a region in which the mode field diameter at the tip surface (100) is maximum and gradually narrows toward a region boundary (13) between the first region (11) and a second region (12). The tip surface (100) is curved, and the radius of curvature of the tip surface (100) is set so that the direction of travel of an optical signal (L) incident from the tip surface (100) is approximately parallel to the central axis direction of the optical waveguide.

Inventors

OKUTA MICHITAKA
YUKI SAITO
Fukushi Mikiya
Yuan Zixiang

Assignees

日本麦可罗尼克斯股份有限公司

Dates

Publication Date: 20260512
Application Date: 20210520
Priority Date: 20200520

Claims (9)

1. An optical probe for transmitting and receiving an optical signal to and from an optical device, the optical probe being for measuring characteristics of the optical device in a state of being formed on a wafer, the optical probe being characterized in that, The optical waveguide includes a core portion and a cladding portion disposed on an outer periphery of the core portion, the first region continuous to a tip end surface facing the optical device includes a region in which a mode field diameter at the tip end surface is maximum and gradually narrows toward a region boundary between the first region and the second region, The tip surface is curved, the radius of curvature of the tip surface is set so that the traveling direction of the optical signal incident from the tip surface is approximately parallel to the central axis direction of the optical waveguide immediately after the optical signal passes through the tip surface, Assuming that a radius of curvature of the tip end face is R, a numerical aperture of the tip end face is NA, a mode field diameter of the tip end face, that is, a first MF diameter is Ce, a radiation angle of the optical signal incident to the tip end face is 2αm, a refractive index of the core portion at an incident point of the optical signal to the tip end face is nr, a central half angle at the incident point of the tip end face is ω, a refractive angle of the optical signal at the incident point is (ω+β), and the tip end face is flat, a numerical aperture sin (α0) of the tip end face satisfies the following relationship: R=Ce/sin(ω) NA=sin(αm) αm=sin -1 {nr×sin(ω+β)}-ω β=sin -1 {sin(α0)/nr}。
2. The optical probe of claim 1, wherein the probe comprises a probe body, At the region boundary, the mode field diameter of the first region is identical to the mode field diameter of the second region.
3. The optical probe of claim 1, wherein the probe comprises a probe body, The working distance WD between the optical device and the top end surface, the mode field diameter of the top end surface, namely, the first MF diameter Ce, and the radiation angle 2αm of the optical signal incident to the top end surface satisfy the following relation that WD is less than or equal to Ce/tan (αm).
4. The optical probe of claim 1, wherein the probe comprises a probe body, The curvature radius R of the top end surface and the cladding diameter Dr of the optical probe meet the following relation that R is more than or equal to Dr/2.
5. The optical probe of claim 1, wherein the probe comprises a probe body, The surface of the cladding portion is covered with a resin film.
6. The optical probe of claim 1, wherein the probe comprises a probe body, The first region has a structure in which a distal end portion continuous to the distal end face is joined to a joining portion joined to the second region, The mode field diameter of the tip portion is fixed, The die field diameter of the connecting portion is equal to or smaller than the die field diameter of the distal end portion at a joint surface with the distal end portion, and the connecting portion has a region in which the die field diameter gradually narrows from the joint surface in the center axis direction, The length of the distal end portion along the central axis direction is set so that the optical signal incident from the distal end surface passes through the joint surface in parallel with the central axis direction.
7. An optical probe array comprising a plurality of optical probes according to any one of claims 1 to 6 arranged.
8. An optical probe card, comprising: The optical probe according to claim 1 to 6, and An optical probe head holding the optical probe.
9. A method for manufacturing an optical probe for measuring characteristics of an optical device in a state of being formed on a wafer, the optical probe including an optical waveguide including a core portion and a cladding portion disposed on an outer periphery of the core portion, a transmission mode of the optical waveguide being a single mode, the method comprising: preparing an optical fiber having a region in which a mode field diameter gradually narrows from one end in a central axis direction; Grinding the one end into a conical shape to form a conical shape region, and The conical top is taken as an axis to process the top end surface of the conical shape area into a convex curved surface, Wherein a radius of curvature of the distal end surface is set so that a traveling direction of an optical signal incident on the distal end surface is approximately parallel to a central axis direction of the optical waveguide immediately after the optical signal passes through the distal end surface, Assuming that a radius of curvature of the tip end face is R, a numerical aperture of the tip end face is NA, a mode field diameter of the tip end face, that is, a first MF diameter is Ce, a radiation angle of the optical signal incident to the tip end face is 2αm, a refractive index of the core portion at an incident point of the optical signal to the tip end face is nr, a central half angle at the incident point of the tip end face is ω, a refractive angle of the optical signal at the incident point is (ω+β), and the tip end face is flat, a numerical aperture sin (α0) of the tip end face satisfies the following relationship: R=Ce/sin(ω) NA=sin(αm) αm=sin -1 {nr×sin(ω+β)}-ω β=sin -1 {sin(α0)/nr}。

Description

Optical probe, method for manufacturing the same, optical probe array, and optical probe card Technical Field The present invention relates to an optical probe, an optical probe array, an optical probe card, and a method for manufacturing an optical probe, which are used for measurement of an optical device. Background Optical devices in which input and output signals are optical signals are formed on a wafer using silicon photonics techniques. In order to measure characteristics of an optical device in a state of being formed on a wafer, an optical probe is used. In this case, in order to reduce the loss of an optical signal transmitted between the optical device to be measured and the optical probe, the optical device and the optical probe are aligned and the mode field is matched. Prior art literature Patent literature Patent document 1 U.S. patent application publication No. 2006/0008226A1 specification Patent document 2 Japanese patent application laid-open No. 62-31136 Disclosure of Invention Problems to be solved by the invention In the case of optical signal transmission in a single mode, the size of the optical signal terminal of the optical device, the core diameter of the optical probe, and the mode field diameter are in the order of several μm. Therefore, the tolerance of errors in the alignment of the optical signal terminals of the optical device with the tip end surfaces of the optical probes is low, and it is difficult to accurately align the optical device with the optical probes. As a result, in measurement of the optical device, there are cases where measurement time becomes long due to time required for alignment or connection loss increases due to inaccurate alignment. As described above, when an optical signal is transmitted in a single mode, there is a problem that an optical device cannot be efficiently measured. In view of the above, an object of the present invention is to provide an optical probe, an optical probe array, an optical probe card, and a method of manufacturing an optical probe, each of which has a single transmission mode and can efficiently measure an optical device. Solution for solving the problem According to one aspect of the present invention, there is provided an optical probe including a first region and a second region, the first region and the second region being connected so that an optical waveguide having a single mode transmission mode is continuous. The first region continuous to the top end face opposite to the optical device includes a region where the mode field diameter at the top end face is maximum gradually narrowing toward a region boundary of the first region and the second region. The tip surface is curved, and the radius of curvature of the tip surface is set so that the traveling direction of the optical signal incident from the tip surface is approximately parallel to the central axis direction of the optical waveguide. ADVANTAGEOUS EFFECTS OF INVENTION According to the present invention, an optical probe array, an optical probe card, and a method for manufacturing an optical probe, each of which has a single transmission mode and can efficiently measure an optical device, can be provided. Drawings Fig. 1 is a schematic cross-sectional view showing the structure of an optical probe according to a first embodiment. Fig. 2 is a schematic view for explaining the refraction angle at the tip end surface of the optical probe according to the first embodiment. Fig. 3 is a schematic diagram for explaining the maximum working distance. Fig. 4 is a graph showing the relationship between the radius of curvature of the tip surface of the optical probe and the numerical aperture. Fig. 5 is a graph showing a relationship between a radius of curvature of a tip surface of an optical probe and a spot radius of an optical signal. Fig. 6 is a graph showing a relationship between positional deviation and connection loss. Fig. 7 is a graph showing the relationship between the radius of curvature of the tip surface of the optical probe and the spot length. Fig. 8A is a schematic view (first) for explaining a method of manufacturing an optical probe according to the first embodiment. Fig. 8B is a schematic diagram (second) for explaining a method of manufacturing an optical probe according to the first embodiment. Fig. 9A is a schematic diagram showing a structure of an optical probe array according to the first embodiment. Fig. 9B is a schematic top view showing an example of an optical waveguide of an optical device. Fig. 10 is a schematic diagram showing the structure of an optical fiber of a comparative example. Fig. 11 is a schematic diagram showing a configuration of a measurement system using the optical probe according to the first embodiment. Fig. 12 is a schematic diagram showing a configuration of a measurement system according to a modification of the first embodiment. Fig. 13 is a schematic view showing a structure of an optical probe according to a