Planar-waveguide external cavity laser stabilization for an optical link with 10(-19) frequency stability.

Area of Science:

• Physics
• Optical Engineering
• Laser Technology

Background:

• Fiber lasers (FLs) are commonly used in optical links but can be expensive and fragile.
• External cavity lasers (ECLs) offer potential advantages in cost-effectiveness and robustness.
• Stabilizing laser frequency is crucial for high-performance optical communication systems.

Purpose of the Study:

• To investigate the frequency stabilization of a compact planar-waveguide external cavity laser (ECL).
• To compare the performance of ECLs with fiber lasers (FLs) in a 100 km optical link.
• To assess the suitability of ECLs as a replacement for FLs in optical links.

Main Methods:

• Frequency stabilization of an ECL using a Fabry-Perot cavity (FPC) and a Pound-Drever-Hall (PDH) scheme.
• Achieving a residual frequency stability of 10⁻¹⁴ for the ECL.
• Setting up and testing a 100 km optical link using both ECLs and FLs.

Main Results:

• The ECL achieved a residual frequency stability of 10⁻¹⁴, comparable to FLs using the same PDH locking scheme.
• The 100 km optical link demonstrated a relative stability of 10⁻¹⁹.
• Performance of the optical link was comparable when using either the ECL or the FL.

Conclusions:

• Compact planar-waveguide ECLs can achieve high frequency stability.
• ECLs demonstrate comparable performance to FLs in long-haul optical links.
• ECLs represent a promising, cost-effective, and robust alternative to FLs for optical links.