Objectives

Outcome:

A monolithic microring resonator integrated with a rib waveguide on a TFLN chip that exhibits ultra-high Q factors and ultra-low propagation loss for optical applications.

Objective structures:

A ring-shaped resonator featuring a narrow coupling gap (around 3.8 µm) integrated on a single chip.

Objective properties:

Ultra-high loaded (≈4.29×10^6) and intrinsic (≈4.04×10^7) Q factors, ultra-low propagation loss (0.0091 dB/cm), and high coupling efficiency (~37%).

Key metrics:

  • Loaded Q factor: 4.29×10^6
  • Intrinsic Q factor: 4.04×10^7
  • Propagation loss: 0.0091 dB/cm
  • Coupling efficiency: 37%
  • Coupling gap: 3.8 µm

Procedures

Microring Resonator Fabrication
Cr Film Coating
Equipment:
  • 600 nm-thick chromium
  • LNOI wafer
  • Magnetron sputtering system
Cr Ablation via Femtosecond Laser
Equipment:
  • Cr-coated sample
  • Femtosecond laser direct writing system
Chemo-Mechanical Polishing (CMP)
Equipment:
  • CMP equipment
Cr Mask Removal
Equipment:
  • Cr etching solution
Secondary CMP and High Temperature Annealing
Equipment:
  • CMP equipment
  • Annealing furnace
Q Factor Characterization
Laser Wavelength Sweeping
Equipment:
  • C-band wavelength tunable narrow-linewidth laser diode (TLB-6728, New Focus Inc.)
Light Coupling
Equipment:
  • Lensed fibers
Polarization Adjustment
Equipment:
  • Inline polarization controller
Optical Signal Detection
Equipment:
  • Photodetector (PD, model: 1611, New Focus Inc.)
Transmission Spectrum Analysis
Equipment:
  • Oscilloscope (model: Tektronix MDO3104)