On-chip free beam optics on a polymer-based photonic integration platform

Abstract

This paper presents on-chip free beam optics on polymer-based photonic components. Due to the circumstance that waveguide-based optics allows no direct beam access we use Gradient index (GRIN) lenses assembled into the chip to collimate the beam from the waveguides. This enables low loss power transmission over a length of 1432 µm. Even though the beam propagates through air it is possible to create a resonator with a wavelength shift of 0.002 nm/°C, hence the allowed deviations from the ITU-T grid (100 GHz) are met for ± 20 °C. In order to guarantee reliable laser stability, it is necessary to implement optical isolators at the output of the laser. This requires the insertion of bulk material into the chip and is realized by a 1050 µm thick coated glass. Due to the large gap of the free-space section, it is possible to combine different resonators together. This demonstrates the feasibility of an integrated wavelength-meter.

Light manipulation in three-dimensional photonic integrated circuits using vertically inserted metasurfaces

“…To realize these practical applications, the foremost step is to collimate the beams from the waveguides. The current method of on-chip beam collimation is to adopt the GRIN lenses [10], which have the length in the order of hundreds of micrometers. In this work, we suggest collimating the waveguide output beams using metasurfaces with a thickness of ∼1 μm.…”

Wavelength Locking and Determination in Tunable Lasers by Gain Voltage Measurement

“…Although the functionality of wavelength lockers on chip level for laser applications has been demonstrated [6] by the integration of on-chip free beam optics [7], the cost factor of the components and the optimization of the assembly process have not been pushed far enough yet. It then stands to reason that one should try to reduce the optical components and switch to a purely eclectic measurement.…”