Fibre Optic Variable Attenuators available
Electrical and manual fibre optic variable attenuators are available for a broad range of applications. MEMS, electro-optical, optomechanical versions are available offering ultra-low loss (0.2dB), high attenuation (>65dB), ultra-high-speed (100ns), programmable, and a vast range of wavelengths and fibre types including large core fibre (up to 1mm ф) and polarisation maintaining fibre.
Applications include power equalisation in multi-channel optically amplified network, transmitter and receiver power control, and gain-tilt control in optical amplifiers OADM power balance.
In respect of thermal actuated MEMS VOAs these have the smallest size, the highest attenuation level, and ultra-high reliability. The Fibre-Fibre MEMS VOAs offer high performance near-lossless, ultra-broadband, and all-type fibres. The high-precision programmable VOAs (0.1dB accuracy 1-40dB, 0.6dB accuracy 40-65dB, 80dB attenuation) are based on Piezo actuation they have a built-in position sensor achieving high stability/repeatability as well as linearity. For high-speed operation, there are solid-state VOAs with low loss, vibration insensitive, fast rise/fall times in addition to variable splitting ratio/splitter.
In-line fixed attenuators - there are two types of; adaptor plug and fibre versions with or without connectors.
Manual variable fibre optic attenuators - there are two types; a fibre collimator based and fibre to fibre direct coupling featuring ultra-low loss, ultra-broadband, ultra-high extinction, and all-fibre types.
MEMS variable fibre optic attenuators (VOAs) offer low insertion loss, low WDL/PDL and lower cost. The MEMS VOAs are conveniently controllable by directly applying a voltage. There are a wide range of configurations covering single-mode, multimode, and polarisation-maintaining, single-channel, multi-channel and integrated tap versions. These are available as miniature mechanical devices with excellent mechanical properties: virtually no hysteresis, and little fatigue to ensure long service lifetimes.
High speed variable fibre optical attenuators (VOAs) are nonmechanical, with high reliability, vibration insensitive, broad operating wavelength, low loss, ultra-fast sub-millisecond response and a wide operating temperature range from -50°C to +90°C. These VOAs are designed to meet the most mission-critical high speed optical switching applications. They are controlled by an electrical field inside an inorganic optical crystal to facilitate fast light intensity control. With a compensation technique, the output light intensity is highly stable against environmental variations. The switch is controllable by a low voltage with speeds up to 150KHz. The high-speed VOA can also be operated at a fixed 5MHz with full attenuation. With partial attenuation, the high-speed VOA can be modulated up to 500KHz.
Further information can be found here.