Adjustable optical attenuator (VOA) is an important optical fiber in

optical fiber communication system, a dynamic device, mainly used for

the channel in dense wavelength division multiplexing (DWDM) system of

power balance, realize gain flat, dynamic gain balance and balance of

the transmission power.And because digital adjustable optical

attenuator control is simple, small volume, good optical performance

and get a bigger development.

Current adjustable optical attenuator has been widely used in the

field of optical communication in communication equipment, general

practice is integrated in the equipment digital adjustable optical

attenuator, through equipment software according to the needs of the

system the attenuation of the adjustable optical attenuator

adjustment, due to VOA integrated into devices, optical path must also

be integrated in the equipment, and fixed, which makes the light path

system is not flexible configuration, and in DWDM systems, different

sites, different transmission capacity is flexible according to the

actual network configuration, and VOA as important configurable device

in the system, not as the system configuration and flexible choice,

the flexibility of the system equipment, increased the system cost.

In the field of optical communications, SFP pluggable transceiver

module as a standard device, because of its small size, mechanical and

optical interface standard unified, flexible and configurable features

such as pluggable, has been widely applied in the system devices. To

make the VOA module could be like sfp transceiver module can be

configured as a flexible application of the device to the system, this

paper presents a VOA module will be integrated into the SFP package,

using standard mechanical and optical SFP interface, so VOA module

could be like fiber optic transceiver module and play, very easy to

achieve light attenuation choice.

As a result of SFP package volume has been greatly restricted, and

based on MEMS (Micro-Electro-Mechanical Systems, MEMS) relative to

other types of VOA prominent feature is the small size of VOA's

technology, simple control, and has good optical properties.

Therefore, this article uses MEMS VOA module SFP package digitally

adjustable attenuator.

1. digital MEMS VOACommon MEMS VOA are mirror rotation and

displacement shade, etc.Either type of light power attenuation, is

through the light attenuation and rotation or movement of the MEMS

chips machinery is one-to-one relationship, and in the chip of

mechanical rotating or moving again and add in the voltage on the top

and bottom plates were one-to-one correspondence relationship,

therefore, is one to one correspondence relation between attenuation

and voltage, but the attenuation is not linear relationship to the

driving voltage.In order to realize digital attenuation control, need

to increase the control circuit, advance the attenuation data stored

in the circuit, voltage curve through customer send attenuation

automatically search the corresponding attenuation voltage, then send

to VOA driving circuit, driving circuit and output the corresponding

voltage to VOA, so as to realize the corresponding attenuation, thus

achieve the goal of the digital control.

2. Based on the SFP package based digital adjustable optical

attenuator
SFP-based package represented by the variable optical attenuator

section, the optical module MEMS VOA, part of the LC optical port, an

electrical control unit CU, electrical interface, the structure and

composition shown in Figure.

In structural terms, the use of standard SFP package

3 adjustable optical attenuator based on SFP packaging

applicationsAdjustable optical attenuator based on SFP encapsulation

performance indicators and MEMS digital adjustable optical attenuator

indicators are similar, with fast response, good linearity and high

stability, high attenuation, such as optical performance, at the same

time, the adoption of SFP encapsulation, make the digital adjustable

attenuator became an independent optical module, support hot plug and

plug and play, do not need to be integrated into the equipment,

equipment for as long as you set aside SFP interfaces, can according

to the requirements of the system, the flexible configuration need

adjustable attenuator, make the light path system is flexible and

simple, at the same time, because of its flexible configuration, save

the cost of the system net change growth, reducing the overall cost

optical network equipment.

4 conclusionAdjustable optical attenuator based on SFP encapsulation

in optical devices tend to be pluggable optical device of the trend,

with the portable flexible characteristics of 10g sfp module, at the same

time with the traditional similar optical properties to the adjustable

optical attenuator, very suitable for WDM systems is applied to the

complicated equipment, flexible of all kinds of network applications,

therefore has wide application prospect.

Posted by: mikofy at 04:28 AM | No Comments | Add Comment
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