MPI-800 Multipath Interference Meter

Helps ensure good transmission in ultra-long-haul networks
Measurement range of –55 dB to –20 dB
All-in-one: an MPI meter, a power meter and a light source
in a single unit
Flexible: available with various ITU-specified sources in the
C and L bands
Next-Generation Network Assessment
Multipath Interference Meter
Measuring Multipath Interference in RamanAmplified Networks
Quality of service and uptime are keystones of the deployment and maintenance of any fiberoptic network. Operators constantly focus on optimizing the former and maximizing the latter—
which, in the case of next-generation networks that use distributed Raman amplification,
can be threatened by the presence of multipath interference (MPI).
MPI is created by the transmitted signal and its amplified reflections reaching the receiver with
an important delay, causing the bit error rate to increase. Measuring it at each critical point
(Raman amplifiers, receivers, etc.) along the network is therefore an essential step toward
ensuring first-class network services.
Enter EXFO’s MPI-800-NS331 Multipath Interference Meter, the only portable MPI
measurement instrument on the market today. It combines a detector and a DFB light source,
providing accurate MPI results in the –55 to –20 dB range. The MPI-800-NS331 offers three
operating modes and packs an MPI meter, a power meter and a light source in a single unit,
making it the ideal tool for characterizing fiber and system components in the field.
Fast, compact and easy-to-use
Measurement range of –55 to –20 dB, with an accuracy of ± 0.7 dB
Available with various ITU-specified sources in the C and L bands
DFB laser source delivering adjustable output power over the –11.5 to 1 dBm range
Convenient: transmitter and receiver combined in one lightweight instrument
All-in-one: an MPI meter, a power meter and a light source for complete fiber and system components characterization
Detection of ASE noise to prevent incorrect interpretation of results
Multipath Interference Meter
Multipath Interference (MPI) Affects
Transmission Quality
In fiber-optic links that include reflective connections, a small portion of the transmitted light can bounce between connectors and reach
the receiver significantly later than light following the direct path. If the link uses distributed Raman amplification, these reflections are
even amplified along the way.
Reflective connections
Direct path
Direct to reflection
path power ratio
Reflected path
The ratio of the direct path to the reflected path is called multipath interference (MPI). With high MPI—as is often the case with Raman
amplification—comes substantial interference, causing increased bit error rate.
The Concept Behind EXFO’s MPI-800-NS331
The MPI-800-NS331 provides accurate assessment of the MPI level by using its low-noise DFB light source to simulate the transmitted
signal and its photodiode detector to measure intensity noise over a given frequency. What’s more, it combines the light source and the
detector in the same unit, making it the obvious choice for complete fiber and system components characterization in the field.
A Field-Proven Design
EXFO’s MPI-800-NS331 Multipath Interference Meter was designed to provide technicians with a portable, rugged and convenient
solution to their installation and maintenance needs.
Portable: The compact, handheld MPI-800-NS331 is powered by a battery that offers an autonomy of 20 hours.
Rugged: The MPI-800-NS331’s tough shell and rubber bumpers enable it to easily survive splashes, knocks
and temperature extremes.
Convenient: The built-in transmitter/receiver combination eliminates the need to worry about the Tx or Rx when characterizing
a long-haul link; the all-in-one MPI-800-NS331 simplifies component and fiber characterization in the field.
Multipath Interference Meter
MPI meter specifications
Measurement range (dB)
Uncertainty a, b, c (dB)
Power range for MPI measurement (dBm)
Display resolution (dB)
Power meter specifications
Measurement range (dBm)
Calibrated wavelengths (nm):
DC power uncertainty a, d (dB)
Linearity (typical)2 (dB)
Display resolution (dB)
Optical source specifications
Source type
Wavelength uncertainty a (pm)
Wavelength stability for 15 min, 1 h, 7 h e (pm)
Output power (dBm)
Output power stability for 15 min a, e (dB)
Output power stability for 7 h a, e (dB)
–20 to –55
± 0.7
6 to –10
6 to –50
1310, 1500, 1510, 1520, 1530,
1540, 1550, 1560, 1570, 1580,
1590, 1600, 1610, 1620, 1630.
± 0.5
± 0.1 (4 dBm to –30 dBm)
0.01 (> –35 dBm)
0.1 (–35 dBm to –44 dBm)
(–44 dBm to –50 dBm)
± 10
± 2.2
–11.5 to 1
± 0.02
± 0.06
Display refresh rate
Size (H x W x D)
2 Hz
0 °C to 40 °C
(32 °F to 104 °F)
−40 °C to 70 °C
(−40 °F to 158 °F)
1.0 kg
(2.2 lb)
23.5 cm x 12.5 cm x 6.7 cm
(9 1/4 in x 4 15/16 in x 2 5/8 in)
Autonomy a (h)
Charge time a (h)
Battery type
Standard accessories include Instruction Manual, AC adapter/charger, built-in
rechargeable Li-ion batteries pack, carrying case, protective holster, shoulder strap
and Certificate of Calibration
21 CFR 1040.10
IEC 60825-1
CLASS 1 Laser Product
CLASS 1 Laser Product
a. At 23 °C ± 1 °C
b. After offset nulling
c. Using the source of the MPI meter and for back reflection less than –30 dB.
d. For a FC/APC connector that has a loss of less than 0.2 dB.
e. The stability is expressed a ± half the difference between the maximum and minimum values measured during
the period.
MPI-800-NS331 = MPI meter with ITU
wavelength 1599.320 nm
EA-EUI-28 = UPC/DIN 47256
EA-EUI-89 = FC narrow key
EA-EUI-91 = SC
EA-EUI-95 = E-2000
EXFO is certified ISO 9001 and attests to the quality of these products. This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference, and (2) this device
must accept any interference received, including interference that may cause undesired operation. EXFO has made every effort to ensure that the information contained in this specification sheet is accurate. However, we accept no responsibility for
any errors or omissions, and we reserve the right to modify design, characteristics and products at any time without obligation. Units of measurement in this document conform to SI standards and practices. In addition, all of EXFO’s manufactured
products are compliant with the European Union’s WEEE directive. For more information, please visit Contact EXFO for prices and availability or to obtain the phone number of your local EXFO distributor.
For the most recent version of this spec sheet, please go to the EXFO website at
In case of discrepancy, the Web version takes precedence over any printed literature.
© 2008 EXFO Electro-Optical Engineering Inc. All rights reserved.
Printed in Canada 08/12