Testing method and testing device

1. A testing method for testing a jointed condition of a first ferrule holding an edge of an optical waveguide and a second ferrule holding an edge of an optical fiber, comprising:

dipping the first ferrule and the second ferrule that are jointed to each other into coolant so that the optical waveguide and the optical fiber are optically connected;

heating the coolant;

cooling the coolant after the heating;

inputting a light to one of the optical waveguide and the optical fiber after cooling the coolant, and detecting a light output from the other.

2. The testing method as claimed in claim 1 , wherein the heating is performed before dipping the first ferrule and the second ferrule into the coolant.

3. The testing method as claimed in claim 1 , further comprising;

inputting a light from one of the optical waveguide and the optical fiber, and detecting the light output from the other, before cooling the coolant.

4. The testing method as claimed in claim 1 , wherein, in the dipping of the first ferrule and the second ferrule into the coolant, an inputting circuit for inputting a light to the optical waveguide and the optical fiber is dipped into the coolant.

5. A testing device for testing a jointed condition of a first ferrule holding an edge of an optical waveguide and a second ferrule holding an edge of an optical fiber, comprising;

a tank configured to house the first ferrule and the second ferrule which are jointed to each other so that the optical waveguide and the optical fiber are optically connected to each other;

a first storage tank configured to store heated coolant;

a second storage tank configured to store cooled coolant;

a first sender configured to send the coolant heated by the first storage tank, to the tank; and

a second sender configured to send the coolant cooled by the second storage tank, to the tank; and

a detector configured to detect a light output from one of the optical waveguide and the optical fiber,

wherein the first sender sends the heated coolant to the tank so that the first ferrule and the second ferrule are dipped into the heated coolant,

wherein the second sender sends the cooled coolant to the tank from the second storage tank so that the first ferrule and the second ferrule are dipped into the cooled coolant after the first ferrule and the second ferrule are dipped into the heated coolant,

wherein the detector is configured to detect a light output from one of the optical waveguide and the optical fiber after the first ferrule and the second ferrule are dipped into the cooled coolant.

6. The testing device as claimed in claim 5 , wherein the detector is configured to detect a light that is input from one of the optical waveguide and the optical fiber and is output from the other, before the first ferrule and the second ferrule are dipped into the cooled coolant.

7. The testing device as claimed in claim 5 , wherein the tank houses the first ferrule, the second ferrule and an inputting circuit for inputting a light to the optical waveguide and the optical fiber.