1030nm 대역 통과 필터(Yb:YAG)

US8811461B2 - High power fiber laser system with ASE suppression

Context: A multi-stage "Master Oscillator Power Amplifier" (MOPA) system where low-power signals are boosted to kilowatt levels.

Usage of Filter: The filter is typically employed as an inter-stage spectral gate (e.g., between the pre-amplifier and the main power amplifier).

Function: Its role is temporal and spectral cleaning. It strips away the broadband ASE "noise floor" that accumulates around the 1030 nm signal after the first stage of amplification.

Result: This achieves high-contrast signal amplification. By removing the noise before the final high-gain stage, the system ensures that the massive energy of the main amplifier is used only to amplify the desired signal, preventing "parasitic lasing" and ensuring a clean, high-power output beam.

US20230029316A1 - Fiber laser frequency tuning with intracavity spectral filter

Context: A mode-locked fiber laser designed for generating ultrashort pulses with tunable wavelengths.

Usage of Filter: The bandpass filter is placed inside the laser cavity (intracavity) rather than at the output.

Function: It acts as a spectral forcing element. By adjusting the filter's transmission window within the broad gain bandwidth of Ytterbium (100–150 nm), it forces the laser to oscillate only at the selected frequency (e.g., centered at 1030 nm).

Result: This achieves tunable pulsed operation without destabilizing the mode-locking. It allows the user to shift the center wavelength of the pulses for specific applications (like multi-photon microscopy) while maintaining high pulse quality.

US10374379B2 - Systems, apparatus, and methods for laser amplification in fiber amplifiers

Context: A high-gain fiber amplifier system (likely Ytterbium-doped) where "backward" noise is a critical issue.

Usage of Filter: The filter is disposed specifically between the optical isolator and the gain fiber.

Function: It is designed to transmit the input laser signal (1030 nm) while reflecting the backward-propagating Amplified Spontaneous Emission (ASE).

Result: Instead of just blocking the noise, this configuration recycles the ASE energy. The reflected ASE re-enters the gain fiber and is re-absorbed, effectively "pumping" the fiber again. This protects the upstream isolator from damage and increases the overall efficiency of the amplification by reusing waste light.