Department of Advanced Materials Science, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561, Japan.
Opt Lett. 2011 Jan 15;36(2):238-40. doi: 10.1364/OL.36.000238.
Amplitude modulation of laser light is required for resonant sideband extraction employed in gravitational-wave detectors. Amplitude modulation with electro-optic phase modulators is realized by interferometric phase-to-amplitude conversion. Although two outputs modulated at opposite phases to each other are obtained, usually only one of them is utilized and the other is abandoned. The reuse of this abandoned light improves the power efficiency of the modulation. This can be realized by inverting the modulation phase of one output with a delay line and adding it to the other coherently. Moreover, this system selects a high-efficiency operating point and modulates the light in a linear range. We demonstrate that the modulation system can be operated with a power loss that is due only to the losses of the optical components.
激光的振幅调制对于在引力波探测器中使用的共振边带提取是必需的。电光相位调制器通过干涉相位到振幅的转换来实现振幅调制。虽然可以获得相互反相调制的两个输出，但通常只使用其中一个，而另一个则被丢弃。复用这个被丢弃的光可以提高调制的功率效率。这可以通过使用延迟线反转一个输出的调制相位，并将其与另一个输出相干地相加来实现。此外，该系统选择高效率的工作点，并在线性范围内调制光。我们证明，调制系统可以在仅由光学元件损耗引起的功率损耗下运行。
