Microelectromechanical System Variable Optical Attenuator Research Articles

Retro-Axial VOA Using Parabolic Mirror Pair

This letter presents a design of a microelectromechanical systems variable optical attenuator (VOA) that employs a pair of parabolic mirrors as the retro-reflector, which has obtained a linear relationship over a 62-dB range between the attenuation (in decibels) and the mirror rotation angle (in degrees). The insertion loss measures 0.6 dB thanks to the three-dimentional optical coupling design. The linearity comes from the simultaneous shift and defocus of the laser beam. Compared with the conventional coaxial and cross-axial VOAs, such retro-axial design has the two fibers arranged on the same side and thus facilitates the use of standard packaging formats

Micro-electromechanical systems variable optical attenuator based on nonsilicon surface micromachining technology

A novel, electromagnetically driven variable fiber optic attenuator based on micro-electromechanical system (MEMS) technology is described. The attenuation level is adjusted by changing the microshutter position in the optical path. A new technique, termed "nonsilicon surface micromachining," is used to fabricate the shutter, in which a copper layer was used as the sacrificial layer, and the electroplated FeNi as the structure layer. This scheme provides another way to fabricate the optical microstructure. The optical characteristics of the attenuator are theoretically analyzed, and the result is verified by experiments. The MEMS attenuator has fiber-to-fiber insertion loss less than 3 dB at 1550-nm wavelength, dynamic range greater than 40 dB, 0.2-dB repeatability, and return loss better than 40 dB.

A MEMS VOA Using Electrothermal Actuators

A comprehensive study of electrothermally driven microelectromechanical system (MEMS) variable optical attenuator (VOA) devices using an H-shaped structure is presented in this paper. Based on its unique structural design, a retroreflection-type VOA of smaller footprint is realized. The repeatability and stability of the static and transient characteristics of attenuation behavior at various ambient temperatures are characterized. The fluctuation of attenuation curves under the same driving voltage at the same ambient temperatures is less than plusmn0.1 dB. Again, comparing the attenuation curves measured at 25 degC to 75 degC and at 25 degC to 12.5 degC, the deviation of attenuation under the same driving voltage is within the 0.6-dB range. Within the 40-dB attenuation range, the measured switching time from nonattenuation state to a particular attenuation state or between two attenuation states is less than 10 ms. This electrothermally actuated MEMS VOA also demonstrates the state-of-the-art dynamic attenuation stability that complies with the Telecordia GR1221 regulations, where the dynamic fluctuation of attenuation at 20 dB is less than plusmn0.36 dB under a vibration testing condition of 20 G periodical shocks with frequency from 20 Hz to 2 kHz

Organic amorphous fluoropolymer membrane for variable optical attenuator applications

The paper describes the design, fabrication and testing of a MEMS (micro-electro-mechanical systems) variable optical attenuator (VOA) made from an organic fluoropolymer thin film. The optical attenuation is achieved by changing the radius of curvature of the organic thin film by actuating a pneumatic force. The size of the organic polymer membrane is 4 mm × 4 mm and the measured centre displacement of the organic membrane is as large as 57 µm without any plastic deformation. The mechanical deformation of the fluoropolymer membrane can be simulated by finite element method (FEM) and the optical coupling efficiency is calculated based on the coherent optical transfer function (OTF) of the deformed membrane. The experimental results show that the attenuation range can achieve 25 dB at the wavelength of 1550 nm, which agrees well with the theoretical calculation. The measured wavelength dependence loss is less than 0.5 dB.

MEMS variable optical attenuator using low driving voltage for DWDM systems

A silicon microelectromechanical system (MEMS) variable optical attenuator with fibre connection is reported. The device requires only 8 V driving voltage. It has only 1.5 dB insertion loss, but 45 dB dynamic range, 37 ms response time, and 0.9 dB wavelength dependence loss over the C-band (1528–1561 nm).

A fiber connectorized MEMS variable optical attenuator

A voltage-controlled moving-mirror microelectro-mechanical systems variable optical attenuator is described that has less than 1-dB fiber-to-fiber insertion loss at 1550-nm wavelength and greater than 50-dB dynamic range. The device was configured with a simple feedback circuit to operate as an optical power regulator capable of stabilizing the output power to within 0.26 dB for a 12-dB input power excursion.