| 摘要 |
PURPOSE:To measure not only induced noise but also the amount of a superposed reflected wave, by adding the output of a light emitting source for emitting light having the same wavelength as semiconductor laser to be measured to the laser to be measured as the substitute of a reflected wave. CONSTITUTION:A semiconductive laser 1 to be measured is driven by a high frequency signal generator (a) while a semiconductor laser 2 for oscillating beam having the same wavelength as the laser 1 is driven by a low frequency signal generator (b) and the beam signal (q) of the laser 2 is added to the laser 1 to be measured as the substitute of the reflected beam through a photocoupler 3. Whereupon, irregular noise is induced in a part of a main signal wave (p) in a certan case. When the output of the laser 1 is subjected to envelope detection by a beam receiver 4 and low frequency is selected by LPF 5 to be measured by a low frequency level meter (c), the amount of a superposed reflected wave is cleared and, if a frequency band is selected by BPF 6 to be measured by a wide band level meter (d), an induced noise amount is determined. |
