Single-port, low-speed OC-48 OLIU (LNW31)

Optical specification

The low-speed LNW31 circuit packs meet or exceed SONET OC-48 1310 nm IR-1 specifications and support span lengths up to 20 km.

System specifications

The table below lists the LNW31 system specifications.

Table 10-8: LNW31 optical system specifications

System information	LNW31
Optical Line Rate	2.488 Gb/s
Optical Line Coding	Scrambled NRZ
Optical Wavelength	1310 nm
Performance	SONET Intermediate Reach, IR-1
Temperature Range	Central Office/Commercial (0°C to 70°C)

Transmitter specifications

The table below lists the LNW31 transmitter information.

Table 10-9: LNW31 optical transmitter information

Transmitter information	LNW31
Optical Device Temperature Controller	None
IEC 60825 Laser Classification	Class 1
FDA Laser Classification	Class I
Optical Source	Distributed Feed-Back (DFB) Laser
Faceplate Optical Connector	LC connector

Receiver specifications

The table below lists the LNW31 receiver information.

Table 10-10: LNW31 optical receiver information

Receiver information	LNW31
Optical Detector	PIN
Faceplate Optical Connector	LC connector

Link budgets

The table below lists the LNW31 link budgets.

Table 10-11: LNW31 optical specifications and link budgets

Parameter 1	LNW31 OC-48 IR-1
Minimum Wavelength	1260 nm
Maximum Wavelength	1360 nm
Maximum Spectral Width (Δλ20)	1.0 nm
Maximum Transmitter Power	0.0 dBm
Minimum Transmitter Power	−5.0 dBm
Maximum Received Power (1x10−12 BER)	0.0 dBm
Minimum Received Power (1x10−12 BER)	−18.0 dBm
Minimum System Gain 2	13.0 dB
Dispersion	NA
Optical Path Penalty 3	1.0 dB
Minimum Optical Return Loss 4	24.0 dB
Maximum Receiver Reflectance 4	−27.0 dB
Additional Connector Loss Margin 5	1.5 dB
Additional Unallocated Margin 6	1.5 dB
Minimum Loss Budget 7	0.0 dB
Maximum Loss Budget 8	9.0 dB
Approximate Span Length 9	20 km

Notes:

1. All terminology is consistent with GR-253-CORE, Issue 3. All values are worst-case end of life (EOL). Optical specifications meet or exceed equivalent GR-253-CORE requirements.

2. The System Gain includes connector loss at the transmitter and receiver points S and R in GR-253-CORE, Issue 3.

3. Optical path penalty includes effects of dispersion, reflection, and jitter that occur on the optical path. The optical path penalty for 1310 nm optics is 1.0 dB maximum. The optical path penalty for the 1550 nm optics is 2.0 dB maximum.

4. See GR-253-CORE for more information about these parameters.

5. One additional connector (0.75 dB) on each end is assumed to connect station cable to outside plant.

6. Additional unallocated margin, or safety margin, can be 0−3 dB. Typically, a 1.5 dB value is assumed.

7. The LNW31 does not require an external lightguide build-out (optical attenuator) as part of the connector assembly for optical loopbacks.

8. The stated maximum loss budget equals the System Gain, less the Optical Path Penalty, the Additional Connector Loss Margin, and the Additional Unallocated Margin. The resultant Maximum Loss Budget is available for station cable loss, transmission cable loss, and splice loss.

9. The approximate span length values are calculated per an attenuation assumption. As a general rule, for attenuation-limited systems, an attenuation of 0.45 dB/km is used for 1310 nm optics. This estimate includes typical cable loss (0.40 dB/km) and up to 11 splice losses (0.2 dB per splice). For 1310 nm OC-48 systems, dispersion is not a limiting factor, and the applications are attenuation-limited. Approximate Span Lengths can be calculated more precisely based on particular fiber and splice characteristics and local engineering rules.

Alarm thresholding

The following parameters are monitored on the OC-48 interface:

• LOS

• LOF

• AIS-L

• RFI-L (FERF)

• Signal Degrade (BER)

• Signal Fail (BER)

Performance monitoring

SONET line and path performance monitoring complies with the standards outlined in GR-253-CORE. For detailed PM parameter thresholds on the OC-48 interface, see Performance monitoring.