Application Cases

Experiment Name: Application of High-Voltage Amplifier in Research on Novel Narrow Linewidth Wavelength-Swept Fiber Lasers

Experiment Objective: To construct and experimentally validate a DCR-CC filter based on simulation parameters, and to build a single-longitudinal-mode narrow linewidth wavelength-swept fiber laser based on the DCR-CC filter and C+L-band EDFA, while investigating its performance.

Experimental Equipment: Filter, function generator, ATA-2021H high-voltage amplifier, etc.

Experimental Procedure:

1. DCR-CC Construction and Characterization:
   A DCR-CC filter was constructed using parameters with cavity lengths of 50.70 cm and 52.00 cm, and its filtering performance was measured using the system shown in the figure.

2.Achieving C+L Band Laser Gain Range:

The structure of the proposed C+L-band single-longitudinal-mode narrow linewidth wavelength-swept fiber laser is shown in the figure. The two sections are connected in parallel via two C/L-band wavelength division multiplexers. A custom DCR-CC composite resonant cavity filter serves as a wide-range filtering element to select a single longitudinal mode from the dense main cavity longitudinal modes, while an FFP-TF acts as the wavelength-swept element, driven by a function generator and a high-voltage amplifier (ATA-2021H). Components within the dashed box, including the FFP-TF, can be replaced by Cir-2 and an FBG to measure the static laser output performance.

Experimental Results:

1. The figure shows the mid-term laser operation stability at four wavelengths over 60 minutes. Measurements were performed using an OSA with a resolution of 0.02 nm and a data acquisition interval of 0.001 nm. The results show that the wavelength fluctuations Δλ_i (i=1,2,3,4) for the four lasers are very small, with a maximum of 0.006 nm. The power fluctuations ΔP_i (i=1,2,3,4) are also very low, with a maximum of 0.704 dB, and the optical signal-to-noise ratios (OSNR) are all above 66 dB.

2.The beat frequency spectra measured by ESA under different sweep frequencies using the self-heterodyne method.

The high-voltage amplifier ATA-2021H used in the experiment provides a maximum output of 200 Vp-p (±100 Vp), capable of driving high-voltage loads. The voltage gain is digitally adjustable, and settings can be saved with a single button, offering convenient and simple operation. It can be used with mainstream signal generators to achieve perfect signal amplification.

Experimental Conclusion:
For FDML wavelength-swept lasers, the laser performance can be further improved by increasing the gain and using high-speed tunable filters with narrower bandwidths. Designing a composite resonant cavity filter more suitable for the FDML mechanism is expected to further enhance the longitudinal mode characteristics of the laser.

Figure: ATA-2021B High-Voltage Amplifier Specifications and Parameters