Single-port, high-speed OC-48 OLIUs (LNW27, LNW29, LNW32, and LNW76)

Optical specification

LNW27 and LNW32

The high-speed LNW27 and LNW32 OC-48 interfaces meet or exceed SONET OC-48 1310 nm LR-1 specifications.

The LNW32 is hardened for outside plant (OSP) temperature ranges; the LNW27 is not.

These interfaces supports span lengths up to 51 km. In OSP environments, the LNW32 support spans of 49 km.

LNW29

The high-speed LNW29 interface meets or exceeds SONET OC-48 1550 nm LR-2 specifications and supports span lengths up to 81 km.

LNW76

The high-speed LNW76 meets or exceeds SONET OC-48 1310 nm SR-1 specifications and supports span lengths up to 2 km.

System specifications

The table below lists the LNW27, LNW29, LNW32, and LNW76 system specifications.

Table 10-4: LNW27, LNW29, LNW32, LNW76 optical system specifications

System information	LNW27	LNW29	LNW32	LNW76
Optical Line Rate	2.488 Gb/s
Optical Line Coding	Scrambled NRZ
Optical Wavelength	1310 nm	1550 nm	1310 nm
Performance	SONET Long Reach, LR-1	SONET Very Long Reach, LR-2	SONET Long Reach, LR-1	SONET Short Reach, SR-1
Temperature Range	Central Office/Commercial (0°C to 70°C)		OSP hardened/Industrial (−40°C to 85°C)	Central Office/Commercial (0°C to 70°C)

Transmitter specifications

The table below lists the OC-48 transmitter information.

Table 10-5: LNW27, LNW29, LNW32, LNW76 optical transmitter information

Transmitter information	LNW27	LNW76
Optical Device Temperature Controller	None
IEC 60825 Laser Classification	Class 1
FDA Laser Classification	Class I
Optical Source	Distributed Feed-Back (DFB) Laser	Fabry-Perot (FP) Laser
Faceplate Optical Connector	LC connector

Receiver specifications

The table below lists the OC-48 receiver information.

Table 10-6: OC-48 optical receiver information

Receiver information	LNW27		LNW29	LNW32	LNW76
Optical Detector	Avalanche Photo Diode (APD)				InGaAsP PIN
Faceplate Optical Connector	LC connector

Link budgets

The table below lists the OC-48 link budgets.

Table 10-7: OC-48 optical specifications and link budgets

Parameter¹	LNW27 OC-48 LR-1	LNW29 OC-48 LR-2	LNW32 OC-48 LR-1	LNW76 OC-48 SR-1
Minimum Wavelength	1280 nm	1500 nm	1280 nm	1266 nm
Maximum Wavelength	1335 nm	1580 nm	1335 nm	1360 nm
Maximum Spectral Width (Δλ₂₀)	1.0 nm	1.0 nm	1.0 nm	−4.0 nm
Maximum Transmitter Power	+3.0 dBm	+3.0 dBm	+3.0 dBm	−3.0 dBm
Minimum Transmitter Power	−2.0 dBm	−2.0 dBm	−2.0 dBm	−10.0 dBm
Maximum Received Power (1x10⁻¹² BER)	−8.0 dBm	−8.0 dBm	−8.0 dBm	−3.0 dBm
Minimum Received Power (1x10⁻¹² BER)	−29.0 dBm	−29.0 dBm	−29.0/−28.0 dBm¹⁰	−18.0 dBm
Minimum System Gain²	27.0 dB	27.0 dB	27.0/26.0 dB¹⁰	8.0 dB
Dispersion	NA	1600 ps/nm	NA	NA
Optical Path Penalty³	1.0 dB	2.0 dB	1.0 dB	1.0 dB
Minimum Optical Return Loss⁴	24.0 dB	24.0 dB	24.0 dB	24.0 dB
Maximum Receiver Reflectance⁴	−27.0 dB	−27.0 dB	−27.0 dB	−27.0 dB
Additional Connector Loss Margin⁵	1.5 dB	1.5 dB	1.5 dB	1.5 dB
Additional Unallocated Margin⁶	1.5 dB	1.5 dB	1.5 dB	1.5 dB
Minimum Loss Budget⁷	11.0 dB	11.0 dB	11.0 dB	0.0 dB
Maximum Loss Budget⁸	23.0 dB	22.0 dB	23.0/22.0 dB¹⁰	4.0 dB
Approximate Span Length⁹	51 km	81 km	51/49 km¹⁰	2 km

Notes:

All terminology is consistent with GR-253-CORE, Issue 3. All values are worst-case end of life. Optical specifications meet or exceed equivalent GR-253-CORE requirements.
The System Gain includes connector loss at the transmitter and receiver points S and R in GR-253-CORE, Issue 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 maximum.
See GR-253-CORE for more information about these parameters.
One additional connector (0.75 dB) on each end is assumed to connect station cable to outside plant.
Additional unallocated margin, or safety margin, can be 0−3 dB. Typically, a 1.5 dB value is assumed.
For all packs and PTMs where the Minimum Loss Budget (MLB) is 0, no attenuator is required for loopbacks. For all packs and PTMs where the MLB is greater than 0, an attenuator is required. The value of the LBO must be equal to or greater than the MLB.
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.
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. For 1550 nm optics, an attenuation of 0.27 dB/km is used. Again, appropriate fiber-cable loss and numerous splice losses are included. For long-reach 1550 nm applications, dispersion may be a limiting factor. Approximate Span Lengths can be calculated more precisely based on particular fiber and splice characteristics and local engineering rules.
The LNW32 is an environmentally hardened OLIU; it is capable of operating in outside plant temperature ranges. The first number applies to deployments in standard CO applications; the second number applies to deployments where temperature excursions (found in OSP environments) may occur.

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.