We present spectral narrowing of a multi-longitudinal-mode diode laser by locking the diode to a Whispering Gallery Mode (WGM) microresonator. By controlling both the temperature and polarization of the diode laser, locking may occur to different TE and TM modes of the microresonator. Fine tuning the laser diode's temperature from 15 °C to 35 °C, makes it possible to lock the laser to 19 different WGMs, resulting in a single longitudinal mode, 2 mW laser, with spectral tunability of 15 nm, and power loss of less than 10%. The WGMs to which the diode laser is locked are calculated and identified. This reported 'in-fiber' system can be packaged to form a simple, cheap, and compact tunable single mode laser device.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering