(i) Technical Field
The present invention relates to a testing method of a semiconductor laser and a laser testing device.
(ii) Related Art
FIG. 1 illustrates a block diagram of a laser testing device for measuring a bit error rate that is one of transmission property tests of a modulation signal. As illustrated in FIG. 1, a laser device 101 is coupled to a light-receiving device 103 through an optical fiber 102 and a variable attenuator 107.
A controller 104 includes a pattern generator 105 and an evaluation unit 106. The pattern generator 105 inputs a given test data pattern into the laser device 101. Then, the laser device 101 outputs an optical signal according to the test data pattern. The optical signal gets to the light-receiving device 103 through an optical fiber 102 having a given length. The evaluation unit 106 evaluates data of the optical signal obtained through a through line in synchronization with the output data of the pattern generator 105 with use of an electrical signal from the light-receiving device 103. And, the controller 104 controls attenuation amount of the variable attenuator 107.
The laser testing device evaluates degradation (bit error rate) of an optical signal getting to the light-receiving device 103 with respect to the changing of the attenuation amount of the variable attenuator 107, and determines the laser device 101 as defective or non-defective. For example, Japanese Patent Application Publication No. 1-204491 discloses the above-mentioned laser testing device.