raman amplifier fiber splicing

Fiber Splicing Required for Connecting High-Power RAMAN

Amplifier to ODF INTERNAL

2008-10-18 Huawei confidentiality. No spreading without permission. Page 1 of 5

Fiber Splicing Required for Connecting High-Power

RAMAN Amplifier to ODF

In a WDM transmission system, a high-power RAMAN amplifier is

always used to amplify the optical power in a single span. For such

application, connect the RAMAN amplifier to ODF by means of fiber splicing.

See the following figure.

It is considerably risky to connect a RAMAN amplifier to ODF through

FC-FC connectors instead of by using fiber splicing in the following aspects:

1. Personal injuries, such as severe skill burn or eye damage, may be caused in

the course of disconnecting the connector or connecting the fiber, as shown in

the following figure. The high-power lasers are always fire hazards and may

easily cause fire in the equipment room.

2. If the fiber is not spliced at ODF, fiber section may easily be burned because

of excessively high PRC pump optical power (30 dBm to the maximum; laser

safety class: CLASS4). The burned fiber section cause much insertion loss and

resultant service interruption.

The FC fiber section may easily be burned if the optical power exceeds 500

mV (approximately 27 dBm).Excessively high optical power may probably

burn the fiber section because the glue used in ceramic ferrule to fix the fiber

core cannot endure such high optical power.

An active FC-FC connector may absorb minor dust particles, such as




metal particles. The dust contains minor particles composed of carbon

molecules, which easily degrade optical power and resultantly cause bit

errors or even service interruption during communication. This always

happens when the optical power reaches 50 mV (approximately 17 dBm).See

the following figure.

Hence, in the case of high-power lasers such as RAMAN, do not use

connectors with metal sleeves, such as FC and ST connectors, when feasible.

Such connectors, when used for many times, may easily cause metal particles.

The LSH/APC-LSH/APC connectors (namely E2000-E2000) are

recommended, because they have plastic sleeves, which do not cause metal

particles.

As backed by previous explanations, a high-power RAMAN amplifier

should be connected to the ODF by means of fiber splicing. If fiber splicing at

ODF is not practically feasible, use the LSH/APC-LSH/APC connector

instead of FC-FC connector to connect the fiber. The LSH/APC connector can

endure high optical power output the RAMAN amplifier. Normally, a fiber

section, if clean, does not get burned.

Appendix I: Details on FC/PC connector and LSH/APC connector




Type Item Spec. Personal

Impact

Precaution for Deployment

and Maintenance

Structural Feature

Possibility to Get

Burned

Max.

endured

optical

power

1 W

Insertion

loss 0.4 dB

Return

loss 45 dB

FC/

PC

Tempera

ture

40 to

75

The

connector

does not have

a protection

shield at the

output port.

Hence,

personal

injuries, such

as severe skill

burn and

damage to

eyes, may be

caused in the

course of

disconnecting

the connector

or connecting

the fiber.

1. Do not remove the fiber

jumper that connecting the

RAMAN board to ODF,

unless when necessary.

Disable the RAMAN laser or

power off the RAMAN

board before removing the

fiber jumper.

2. Before removing the fiber

jumper, observe the fiber

section with a fiber

microscope and make sure

that the fiber section is clean.

Before observing the fiber

section, make sure that the

fiber section does not output

light, which may cause eye

damage.

3. Do not point the fiber

jumper port with output

light at anybody.

4. Replace the burned fiber

jumper in time; otherwise,

the system performance may

be affected and the fiber

section connected to it may

be burned.

1. Adopts a metal

frame.

2. Uses glue to fix the

fiber. When the

system works with

high optical power,

heat accumulates at

the fiber section and,

when reaches a certain

extent, burns the glue.

Consequently, the

fiber section is burned

and the fiber is

permanently

damaged.

1. Thousands of

removal-and-inserti

ons show that the

fiber section is

dirtied every 15

removal-and-inserti

ons on average and

even once on the

worst.

2. As the connector

is of a metallic

structure, the fiber

section may easily

be dirtied by metal

particles and thus be

burned in the case of

high optical power.

Max.

endured

optical

power

2 W

Insertion

loss

0.15

dB

Return

loss 85 dB

LSH

/AP

C

Tempera

ture

40 to

75

The

connector has

a protection

shield at the

output port,

which

protects the

human body

from direct

exposure to

intensive

1. Do not remove the fiber

jumper connected to the

LINE interface of the

RAMAN board, unless

when necessary.

2. Before removing the fiber

jumper from the LINE

interface of the RAMAN

board, observe the fiber

section with a fiber

microscope and make sure

1. Adopts a plastic

frame.

2. Has a protection

shield at the output

port, which keeps

dusts outside to a

certain extent, and

endures 1 W optical

power all the time and

2 W optical power for

30s. The protection

1. Thousands of

removal-and-inserti

ons show that the

fiber section is

dirtied every 20

removal-and-inserti

ons on average and

even three on the

worst.




light. Hence,

the connector

is safer.

that the fiber section is clean.

Before observing the fiber

section, make sure that the

fiber section does not output

light, which may cause eye

damage.

3. Replace the burned fiber

jumper in time; otherwise,

the system performance may

be affected and the fiber

section connected to it may

be burned.

shield can effectively

protect the human

body from the

RAMAN laser, unless

open manually.

3. Is glue-free. The

connector can work

for two hours even

when the optical

power is as high as 5

W.

No active connectors guarantee no permanent damage caused by high-power

laser to the fiber section, regardless of what structure of the fiber section is

and how the material ensures high optical power. If the fiber section is burned,

replace the fiber jumpers connected to the ODF and RAMAN board.

For more safety of the human body and equipment, connect the RAMAN

amplifier to ODF by means of fiber splicing, which is safer and more reliable.

Appendix II

1. Laser safety classification of Huawei

Class 1 Class 1M Class 3B Class 4

Power P < 10 dBm 10 dBm < P < 21.3 dBm 21.3 dBm < P < 27 dBm P > 27 dBm

2. Laser safety classification of IEC

CLASS 1 These lasers are safe under all operating conditions, even when one

views the inside laser beams of optical components. (optical power <

0.39 mW)

CLASS 1M These lasers launch laser beams in the wavelength range of 302.5 nm to

4000 nm and are safe in general but hazardous exceptionally when one

views the inside laser beams of optical components. (optical power <

0.39 mW)

CLASS 2 These lasers launch visible laser beams in the wavelength range of 400

nm to 700 nm. When accidentally viewing the laser beams, blink eyes for

protection. (0.39 mW < optical power < 1 mW)

CLASS 2M These lasers launch visible laser beams in the wavelength range of 400

nm to 700 nm. It is hazardous to view the inside laser beams of optical




components. (0.39 mW < optical power < 1 mW)

CLASS 3R These lasers launch laser beams in the wavelength range of 302.5 nm to

106 nm. It is hazardous to deliberately stare the laser beams. (1 mW <

optical power < 5 mW)

CLASS 3B There lasers are hazardous when one deliberately stares the laser beams

and safe in general when one views the reflected or diffused laser

beams. (1 mW < optical power < 0.5 W)

CLASS 4 There laser are hazardous even when one views the reflected or diffused

laser beams, and may burn the skin and cause fire. (optical power > 5

W)

raman amplifier fiber splicing

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