Wide-bandwidth Pound-Drever-Hall locking through a single-sideband modulator.

Area of Science:

• Optical physics
• Laser technology
• Control systems engineering

Background:

• Pound-Drever-Hall (PDH) locking is crucial for stabilizing laser frequencies.
• Traditional PDH systems often require complex feedback loops for wide bandwidth control.
• Achieving wide locking ranges and control bandwidths is essential for advanced optical experiments.

Purpose of the Study:

• To demonstrate a simplified Pound-Drever-Hall locking loop using a single wide-bandwidth frequency actuator.
• To investigate the performance of an integrated single-sideband modulator in a PDH locking setup.
• To achieve precise frequency stabilization of a 1.55 μm diode laser coupled to an optical cavity.

Main Methods:

• Utilized an integrated single-sideband modulator as the sole frequency actuator in the PDH locking loop.
• Employed a Pound-Drever-Hall technique for frequency stabilization.
• Coupled an extended-cavity diode laser at 1.55 μm to a high-finesse optical cavity.

Main Results:

• The integrated single-sideband modulator provided a large modulation bandwidth, enabling a ±75 MHz locking range.
• A 5 MHz control bandwidth was achieved without requiring a second feedback loop.
• The in-loop frequency noise spectral density reached a minimum of 1 mHz/Hz(1/2) at 1 kHz.

Conclusions:

• A single-sideband modulator can effectively serve as the sole wide-bandwidth frequency actuator in PDH locking.
• This approach simplifies the PDH locking system and enhances its performance.
• The demonstrated technique is suitable for high-precision laser frequency stabilization applications.