Kyunghun Han and co-workers from the National Institute of Standards and Technology, University of Maryland, and Theiss Research in the USA have developed an on-chip comb spectrometer composed of a Mach–Zehnder interferometer with an electro-optic phase modulator on each arm (pictured).

A diode laser with a wavelength near 1,550 nm was coupled to the input waveguide, which consisted of a Si₃N₄ ridge waveguide with a width of 2.5 μm and a LiNbO₃ slab layer vertically spaced by 100 nm. The electro-optic modulator in the lower arm was driven by a chirped waveform to generate the electro-optic frequency comb, while the upper modulator received a serrodyne modulation to generate a frequency-shifted local oscillator for heterodyne detection.

Kyunghun Han 和来自美国国家标准与技术研究所、马里兰大学和泰斯研究所的同事开发了一种片上梳状光谱仪，由马赫-曾德干涉仪组成，每个臂上都有一个电光相位调制器（如图）。

将波长接近1,550 nm的二极管激光器耦合到输入波导，该输入波导由宽度为2.5 μm的Si ₃ N ₄脊形波导和垂直间隔100 nm的LiNbO ₃板层组成。下臂中的电光调制器由啁啾波形驱动以生成电光频率梳，而上调制器接收锯齿差调制以生成用于外差检测的频移本地振荡器。