633-nm tunable external-cavity diode laser with an intracavity glass plate as the fine-tuning device

Abstract

The application of beatwave Fabry-Perot interferometers (BFPIs) to nonlinearity error calibration is limited by the short tuning range of the slave He-Ne laser. In this paper, a 633-nm tunable externalcavity diode laser (ECL) is proposed as the slave laser of a BFPI. The ECL consists of an antireflection-coated quantum-well laser diode, a collimating lens, and a diffraction grating in Littrow configuration. In addition, an intracavity glass plate is adopted to provide cavity fine tuning, which makes the ECL more convenient, as it is easier to align the light in the cavity. At an optical length of 45 mm, a coarse-tuning range of 4 nm around 633 nm is obtained by rotating the grating. It is also demonstrated that this ECL can operate in a single-mode regime and can be continuously tuned over a frequency range of 1.8 GHz by tilting the intracavity glass plate.