Low Noise Monolithically Integrated Membrane DFB Laser on Silicon

Photonic integration on membranes is a promising solution to heterogeneously combine electronic and photonic functionalities in a single chip. The InP membrane on Silicon (IMOS) platform is an advantageous solution for this, since it can integrate all active and passive devices, such as lasers, detectors and high-index-contrast waveguides, in a single membrane layer. One of the most important components of the platform is the low noise single mode laser. In this work we present a quarter-wavelength shift single mode distributed feedback (DFB) laser with high side mode suppression ratio (SMSR) for the IMOS platform. The DFB grating is defined on top of the semiconductor optical amplifier and has pitch of 240 nm for 1550 nm lasing wavelength. Refractive index difference in single pitch is
$\Delta \mathrm{n} =0.1\%$
. In order to the
$\text{kL}=4$
, the length of the laser should be 1 mm. The laser has a 50 mA threshold current and 2.5 kA/cm
²
threshold current density. The laser is featuring very high SMSR of 60 dB. The maximum output power in the cavity is estimated to be 20 mW. High SMSR and low noise of the laser opens a number of potential applications for coherent communication, spectroscopic sensing and optical metrology.