Narrow Linewidth Semiconductor Laser Based On Single-Wavelength Narrowband Optical Filtering Assembly Frequency Selection

摘要

A narrow linewidth external cavity semiconductor laser comprises semiconductor optical amplifier chip, comb-shaped optical filter, bandpass optical filter, partial reflection sheet, and collimated light beam coupling output assembly Collimated light beam coupling output assembly is composed of isolator, coupling lens, and output optical fiber. Laser resonant cavity is formed by partial reflection sheet and rear end face of semiconductor optical amplifier chip. Comb-shaped optical filter and bandpass optical filter form single-channel narrowband optical filtering assembly. Bandwidth enables laser to perform single-mode lasing and effectively restrain any other mode lasing. Longitudinal mode's relative position over whole filtering band may be controlled by adjusting laser temperature. Output wavelength and laser power are controlled and in best working state. Etalon is used as comb-shaped optical filter to easily realize narrow linewidth output. Commercial DWDM optical filter is used as bandpass optical filter to improve device wavelength flexibility and reduce costs.