JPH02144132U - - Google Patents

Description

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing an embodiment of a semiconductor laser noise measuring device according to the present invention, Fig. 2 is an explanatory diagram showing the shape of a spot on a light receiving element provided for position adjustment of the semiconductor laser, and Fig. 3 4 is a characteristic curve diagram showing relative light intensity noise characteristics with respect to the ratio of the amount of light emitted from the semiconductor laser to the amount of returned light, and FIG. 4 is a configuration diagram showing a conventional device. 20...Laser mounting member, 21...Semiconductor laser, 22...Half mirror, 25...Transmittance variable filter, 26...Objective lens, 27...Mirror, 28...Mirror actuator, 31...Front Light receiving element for cumming error detection, 32... Measurement control circuit, 38... Hologram element, 39... Light receiving element for noise measurement, 40... Light receiving element for semiconductor laser position detection, 41... Voltmeter, 42... spectrum analyzer.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A half mirror that divides the laser beam emitted from the semiconductor laser to be inspected into two and emits it to different optical paths, a member equivalent to an optical disk that reflects the laser beam, and this optical disk. an optical disk-equivalent member actuator that moves the corresponding member in a focusing direction; an optical system that includes at least an objective lens and that irradiates the disk-equivalent member with one laser beam via the half mirror; a focusing servo system that drives the objective lens based on the reflected light and returns through the optical system and the half mirror to perform focusing control on the member corresponding to the optical disk; and the semiconductor laser to be inspected. Based on the laser beam emitted from the laser beam that is not directed to the optical disk equivalent member by the half mirror,
noise detection means for detecting noise characteristics of laser light emitted from the semiconductor laser; and a laser light that is not directed toward the optical disk equivalent member by the half mirror among the laser light emitted from the semiconductor laser to be inspected. On the basis of the,
A semiconductor laser noise measuring device comprising: semiconductor laser position detection means for detecting the mounting position of the semiconductor laser. (2) Mounting position variable means is provided for positioning the mounting position of the semiconductor laser at a predetermined position based on the mounting position detected by the semiconductor laser position detection means, and the noise measuring means is configured to adjust the mounting position of the semiconductor laser to a prescribed position. 2. The semiconductor laser noise measuring device according to claim 1, wherein the noise characteristic is detected after the semiconductor laser is positioned at a predetermined position. (3) The semiconductor laser noise measuring device according to claim 1 or 2, wherein the noise detection means detects relative light intensity noise as the noise characteristic. (4) The optical system is provided with a light amount variable means for varying the ratio between the amount of laser light emitted from the semiconductor laser and the amount of return light from the member equivalent to the optical disk, and the noise detection means 4. The semiconductor laser noise measuring device according to claim 3, wherein the relative light intensity noise at a light amount ratio of is compared with a predetermined threshold value to determine the quality of the semiconductor laser.