컬렉션: 980nm 대역 통과 필터(InGaAs)

Context: High-power diode lasers used for "pumping" (energizing) solid-state or fiber lasers.

Usage of Filter: The system uses an external cavity configuration where a spectral filter (or diffraction grating acting as one) provides feedback to the laser array.

Function: It acts as a Spectral Lock. Standard 980 nm diode bars have a "sloppy" spectrum (wide bandwidth) that shifts with temperature. This filter forces the diodes to lase in a very narrow band centered precisely at 980 nm.

Result: This achieves maximum pumping efficiency. Since the absorption line of Erbium (the medium being pumped) is quite narrow, this "spectral locking" ensures that 100% of the pump energy is absorbed by the fiber, rather than passing through wasted.

Context: Modern consumer electronics (smartphones/automotive) using 3D sensing, gesture recognition, or LiDAR.

Usage of Filter: The patent describes a filter stack specifically designed to pass near-infrared light (including the 980 nm band) while rigorously blocking visible light and other IR noise.

Function: It acts as a Sunlight Blocker. In outdoor environments, the sun blasts the sensor with broad spectrum noise. The 980 nm bandpass filter sits over the detector (SPAD or CMOS) and ensures it only "sees" the specific 980 nm dot pattern projected by the device's laser.

Result: This achieves high Signal-to-Noise Ratio (SNR) in bright ambient light. Without this filter, your Face ID would fail the moment you stepped outside on a sunny day.

Context: Biomedical imaging systems looking deep inside biological tissue (NIR-II window).

Usage of Filter: A bandpass filter is used in the excitation or emission path of a fluorescence microscope/endoscope.

Function: It acts as an Excitation Rejector. In systems using 980 nm light to excite deep-tissue fluorophores (like carbon nanotubes or rare-earth nanoparticles), the detector needs to see the faint glow of the sample, not the blinding 980 nm pump light. The filter blocks the 980 nm reflection while passing the longer wavelength fluorescence.

Result: This achieves high-contrast deep-tissue imaging. It allows surgeons or researchers to see blood vessels or tumors through millimeters of tissue and skin, which is impossible with visible light.