Operating point control method for the Mach-Zehnder modulator in a phase-shift laser range finder

Area of Science:

• Optoelectronics
• Photonics
• Control Systems

Background:

• Mach-Zehnder modulators (MZMs) are crucial optical components.
• Traditional MZM control methods can be affected by noise and drift.
• Stable operating points are essential for precise optical measurements.

Purpose of the Study:

• To propose a novel operating point control method for MZMs.
• To enhance the stability and reliability of MZM-based systems.
• To adapt the control method for phase-shift laser range finders (PSLRFs).

Main Methods:

• A dual-cascaded MZM structure was employed.
• A new control method was developed, avoiding dither signals.
• The method monitors components without spectrum noise floor masking.
• Quadrature point drift direction is clearly determined for stability.

Main Results:

• The proposed method improved MZM operating point stability from ±0.59° to ±0.36° within 2 hours.
• Ranging stability in a PSLRF reached better than 17μm in 1 minute.
• Ranging stability improved to better than 39μm in 1 hour with a 200 MHz modulation frequency.

Conclusions:

• The novel MZM control method offers superior stability compared to traditional approaches.
• The method is well-suited for enhancing the performance of PSLRFs.
• This advancement contributes to more reliable and precise optical sensing applications.