The 1660 nm narrow-bandpass filter is a precision optical component featuring an extremely narrow passband (typically 10–20 nm FWHM) centered around 1660 nm, with deep blocking on both sides reaching up to OD6 (T<0.0001 %). It is fabricated using ion-assisted multilayer hard coating technology on JGS2 or silicon substrates, ensuring dense film layers, low thermal drift, long lifespan, and peak transmittance >95 %.

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Core Functions
? Allows only light within the 1658–1662 nm (±2 nm) range to pass through efficiently
? Provides deep suppression (T<0.0001 %) in the 1500–1620 nm and 1685–1900 nm bands, ensuring high system signal-to-noise ratio

Typical Applications
? Gas analysis: Methane, CO?, etc., have strong absorption lines near 1660 nm, making it suitable for TDLAS detection with lasers

? Fully distributed optical fiber sensing: Utilizes 1660 nm Raman scattering for temperature/strain monitoring over distances up to 100 km

? Machine vision, infrared medical applications, biochemical analysis, handheld ranging, iris/face recognition, and other scenarios

Optional Specifications
Center wavelength 1660 nm±2 nm; FWHM 10 nm, 16 nm, or 20 nm optional; peak transmittance ≥95 %; blocking zone OD5–OD6; dimensions φ8–49 mm or 10×10 mm; thickness 1–4 mm; operating temperature ?40 °C to +85 °C.