Development of small form factor packaged single-mode semiconductor laser for spectroscopic applications at 689 nm. (July 2023) - Ó Dúill, Seán P.
Highlights: This paper reports on a functional packaged single-mode and stable semiconductor laser operating at 689 nm for spectroscopic applications. The key point is that the laser system and coupling optics are all packaged in a form factor compatible with regular 14-pin butterfly packages. The enabling technology is the development of an optical isolator that is small enough to fit inside a small package for the wavelength of 689 nm, we go into detail as to how this was achieved. To verify the claims we present results on the stability of the laser system for: long term power fluctuations, relative intensity noise and frequency noise. Abstract: We report on the development of a compact packaged semiconductor laser capable of spectroscopy applications at 689 nm. The key component is an optical isolator that is small enough to fit inside a package that is compatible with standard 14-pin butterfly packages. We present a threshold current of 33 mA, a forward voltage of 2.5 V at 50 mA, long term reliability study for over 12, 500 h, a relative intensity noise below −145 dBc/Hz, and a linewidth of 1.4 MHz. The relative intensity noise and the frequency noise spectra verify continuous-wave lasing and frequency stability of the packaged laser.