Research-Page of Dominik G. Rabus
Research
Integrated Ring
Resonator Lasers in GaInAsP/InP
Passive Ring
Resonator Coupled Lasers
The research on
ring resonator coupled lasers is performed in collaboration with Prof. Ali Shakouri
and Dr. Bian of the
In a ring resonator
coupled laser (RCL), the frequency-dependent passive mirror with complex
amplitude reflectivity is formed by the combination of a coupled ring resonator
with a reflection facet. This frequency-dependent passive mirror can
considerably extend the effective cavity length and photon lifetime at the
lasing wavelength. Thus, the laser linewidth and the
frequency chirp can be greatly reduced. In addition, a double ring resonator
configuration can be used to extend the wavelength tuning range using the Vernier effect. The photograph of a fabricated double ring
resonator coupled laser is shown in the figure below.
The ring resonators
have a slightly different radius to increase the free spectral range (FSR) and
to achieve a single mode operation. A double ring resonator (DRR) opens the possibility
of expanding the FSR to the least common multiple of the FSR of individual ring
resonators. This is done by choosing different radii in the DRR. In the case of
different radii, the light passing through the DRR is launched from the drop
port when the resonant conditions of the two single ring resonators are
satisfied. The laser cavity consists of SOA1 and SOA2 and the two ring
resonators. The chip length is 2 mm. The remaining SOAs
are not biased and are used as absorbers to suppress lasing of sub cavity
modes.
The spectrum of a
double ring RCL with a FSR of 30 nm is shown in the figure below.
