LioniX has developed a near-infrared ultra-narrow linewidth tunable laser

LioniX International, a provider of integrated photonics and custom MEMS device solutions, has teamed up with an alliance partner in the REAP program to develop an ultra-narrow line-width tunable laser ona chip that addresses the narrow range of near-infrared light. It is described as having a line width of 22 kHz, a tuning range of 45 nm, an output power of 5 dBm and a SMSR of -40 dB.

Hybrid integration of external cavity vernier lasers

The laser also looks simple: a semiconductor optical amplifier connected to the TriPleX® chip feeds directly to the fiber array. The laser's power comes from clever integrated circuits, including vernier filters and two tunable microring resonators implemented on their platform, as well as a Mach-Zehnder interferometer to adjust the efficiency of the output coupling.

To ensure long-term thermal stability, the laser is equipped with a negative temperature coefficient thermistor installed on the photonic integrated circuit, and the thermoelectric cooler is placed in a 14-pin butterfly package. Thermal management, as well as wavelength and output tuning, is electronically regulated with one of their internal laser controllers, developed for use in external cavity lasers.

Fast tuning over a large area

The device has a maximum power output of 5 dBm and a minimum side-mode rejection ratio of -40 dB at a central wavelength of 800 nm. After testing its operation for more than a full day, the laser output showed minimal drift and a constant package temperature of 25°C. The measured light has a natural linewidth of 22 KHZ and a tuning speed of subkhz.

The circuit is made using its 850nm MPW service, which uses transverse waveguide cones to precisely connect the chip to the gain portion and the output fiber. The optical loss of these interfaces can be as low as 0.3 dB at the gain end and 0.4 dB at the fiber end. Their TriPleX® platform also supports vertical waveguide cones, but this is not used in this prototype.

Source: OFweek