Huawei OptiX PTN Series Quick Installation Manual page 39

3 Checking Optical Power
Operation Criteria
The mean transmitted optical power and received optical power must be in the corresponding value ranges that
are listed in Optical Module in the Product Description manual.
To help an optical module keep stably running, set the optical power of the optical module at least 3 dBm more
than the receiver sensitivity or to a middle value between the receiver sensitivity and minimum overload point.
For CFP-100G-SM-40Km optical module, pay attention to the following:
•
The transmission distance of the 100GBASE-ER4 optical module ranges from 10 km to 40 km. When a
transmission distance shorter than 10 km is needed, use the 100GBASE-LR4.
•
To help an optical module keep stably running, set the optical power of a 100GBASE-ER4 (40 km) less than a
single-channel -10 dB and the input optical power less than -4 dB.
•
If the received optical power is lower than -4 dBm, use the 100GBASE-ER4. If the received optical power is
higher than or equal to -4 dBm and lower than or equal to 1 dBm, use the 100GBASE-ER4 with a 5 dB
attenuator on the receive end. If the received optical power is higher than 1 dBm, use the 100GBASE-ER4
with a 10 dB attenuator on the receive end.
When using the optical module CFP-100G-SM-80km, note the following:
•
The maximum transmission distance of the 100GBASE-ZR4 is 80 km. The main transmission distance of the
100GBASE-ER4 is 10 km - 40 km. You can use the 100GBASE-LR4 when a less-than-10 km transmission
distance is required.
•
Checking the receive optical power P is recommended. If P is less than -1 dBm, use the 100GBASE-ZR4. If P
ranges from -1 dBm to 9 dBm, add a 10 dB optical attenuator to the receive end of the 100GBASE-ZR4. If P is
greater than 9 dBm and less than or equal to 13 dBm, add a 15 dB optical attenuator to the receive end of the
100GBASE-ZR4.
For applications of the 50 Gbps optical module supporting a distance of 40 km:
•
To ensure that the optical module runs stably for a long time, adjust the receive optical power of the optical
module to a value lower than -4 dB. According to the IEEE 802.3 standard, if the receive optical power of the
optical module exceeds -2.3 dB, the optical module may be permanently damaged.
•
Before connecting to the optical module, use an optical power meter to measure the receive optical power (P).
If P is less than -4 dB, the optical module can be directly connected. If P is greater than -4 dB, add an optical
attenuator at the receive end to ensure that the receive optical power is less than -4 dB. Alternatively, add an
optical attenuator (no less than 10 dB is recommended) before the interconnection, and then adjust the optical
attenuator based on the site requirements to prevent the optical module from being damaged.
•
If a loopback occurs on the pigtail of the optical module or the optical module is connected for a short distance,
an optical attenuator must be added. It is recommended that the optical attenuator be no less than 10 dB.
Note the following issue when you use CFP-40GE-SM optical modules:
•
A 40GE 10 km/40 km optical module cannot be connected to a 40GE km optical module due to a wavelength
inconsistency.
Checking Optical Link
36