Introduction of Optical Attenuator on Huawei OptiX OSN 1800

Abstract

This article will give you detailed introduction of optical attenuators: its classification and application on Huawei OSN1800.

An optical attenuator, or fiber optic attenuator, is a device used to reduce the power level of an optical signal, either in free space or in an optical fiber. Optical attenuators are classified into fixed optical attenuators and variable optical attenuators (VOAs).

Note: an optical attenuator is optional. That is, it must be purchased separately, if it is required.

 

Classification

Fixed Optical Attenuator

A fixed optical attenuator can reduce the optical power on an optical path by a fixed value. The common attenuation specifications of fixed optical attenuators are 2 dB, 5 dB, 7 dB, 10 dB, and 15 dB.

Figure 1 shows the appearance of a fixed optical attenuator.

Figure 1 Fixed optical attenuator

 

 

Mechanical Variable Optical Attenuator

A mechanical variable optical attenuator (MVOA) can adjust the optical power on an optical path within a permitted range. The attenuation adjustment range of an MVOA is 2 dB to 30 dB.

Figure 2 and Figure 3 show the appearance of common MVOAs.

Figure 2 Dual-channel MVOA

Figure 3 Single-channel MVOA

 

EVOA Module

Definition:

An electrical variable optical attenuator (EVOA) module is used to adjust the optical power of signals.

Note: As pluggable SFP optical modules, EVOA modules are optional. That is, it must be purchased separately, if it is required.

 

Functions

An EVOA module adjusts the optical power of signals by adjusting line attenuation. You can view the attenuation on the NMS.

You can connect the EVOA module to the IN port on the board where the EVOA module resides to adjust the receive optical power of the board. For details, see Figure 4. 

Figure 4 Application of the EVOA module (adjusting the receive optical power of the board)

You can also connect the EVOA module to the OUT port on the board where the EVOA module resides to adjust the transmit optical power of the board. For details, see Figure 5.

Figure 5 Application of the EVOA module (adjusting the transmit optical power of the board)

 

Boards Supporting EVOA Modules

Table 1 describes the boards supporting EVOA modules and the corresponding working modes and ports of the boards.

Table 1 Boards supporting EVOA modules, and corresponding working modes and ports
Board Supporting EVOA Modules	Working Mode	Available Port
F2ELOM(STND)/ELOM(STND)	1*AP8 General Mode	RX1/TX1–RX8/TX8
	1*AP1 ODU2 Mode	RX7/TX7, RX8/TX8
	1*AP1 ODUflex Mode	RX7/TX7, RX8/TX8
F2ELOM(C9LOG)	1*AP1 ODU2 Non-convergence Mode	RX7/TX7, RX8/TX8
ELQM	1*AP4 ODU1 Mode	VO1/VI1–VO2/VI2
	1*AP2 ODU0 Mode	VO1/VI1–VO2/VI2
F2LQM	1*AP4 ODU1 Mode	VO1/VI1–VO2/VI2
	1*AP2 ODU0 Mode	VO1/VI1–VO2/VI2
	1*AP2 Regeneration Mode	VO1/VI1–VO2/VI2
F2LQM2(VA8)	—	RX1/TX1–RX8/TX8
F2LQM2(STND)	1*AP8 ODU1 Mode	RX2/TX2–RX8/TX8
	2*AP4 ODU1 Mode	TX2/RX2, TX3/RX3, TX4/RX4, TX6/RX6, TX7/RX7, TX8/RX8
	2*AP2 ODU0 Mode	RX1/TX1–RX8/TX8
	2*AP3 ODU1 Mode	TX2/RX2, TX3/RX3, TX4/RX4, TX6/RX6, TX7/RX7, TX8/RX8
F2LQM2(C9LQM2)	1*AP8 ODU1 Mode	RX1/TX1–RX8/TX8
	2*AP4 ODU1 Mode	RX1/TX1–RX8/TX8
OBU	—	VO/VI

 

Note: as shown in Table 1, among the boards supporting EVOA modules, the F2LQM2(VA8) and OBU boards support logical fiber connections only when optical ports function as EVOAs.

 

After reading this article, hope you can choose your suitable optical attenuator based your needs. If you still not clear about your requirement, you may contact our experienced and professional support team freely: [email protected]