Does the DDM interface display the actual real-time optical reflection or return loss metrics?

No, the SFF-8472 digital diagnostics monitor real-time temperature, voltage, bias current, and received/transmitted optical power levels.

Do I need a special type of fiber cable to achieve the full 40km transmission distance?

You must use standard single-mode fiber (SMF) cables; multi-mode fiber (MMF) will not work for this long-reach optic.

Can this module survive inside sun-exposed field cabinets during extreme summer heatwaves?

Yes, its ruggedized industrial design ensures stable 25Gbps performance even when internal cabinet temperatures climb near the 85°C limit.

Will the optical receiver get damaged if my fiber run has a lot of sharp bends or splices?

Bends and splices increase link loss but won't damage the hardware, though too much signal loss can cause your 25G link to drop.

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LINK-PP LS-SM3125-40I 25G SFP28 1310nm 40km Duplex LC/UPC DDM SMF Optical Transceiver Module (Industrial)

Name: LINK-PP LS-SM3125-40I 25G SFP28 1310nm 40km Duplex LC/UPC DDM SMF Optical Transceiver Module (Industrial)
Brand: LINK-PP
SKU: 181709
Price: 131.58 USD
Availability: InStock
Rating: 4.9 (39 reviews)

# 181709

Product: LINK-PP LS-SM3125-40I 25G SFP28 1310nm 40km Duplex LC/UPC DDM SMF Optical Transceiver Module (Industrial)
SKU: 181709
P/N: LS-SM3125-40I
Price: $ 153
Stock: 1200 in Stock
Sold: 2.3K
Product URL: https://www.l-p.com/products/476827.htm

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Compatible:: Cisco; LINK-PP; Arista; Brocade; FS; Mellanox

Compatible P/N:: LS-SM3125-02C | 2km; LS-SM3125-02I | 2km; LS-SM3125-10C | 10km; LS-SM3125-10I | 10km; LS-SM3125E-10C | 10km; LS-SM3125E-10E | 10km; LS-SM3125E-10I | 10km; LS-SM3125-20C | 20km; LS-SM3125-20I | 20km; LS-SM3125-30C | 30km; LS-SM3125-30I | 30km; LS-SM3125-40C | 40km; LS-SM3125-40I | 40km

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LINK-PP LS-SM3125-40I 25G SFP28 Specifications

LS-SM3125-40I is an industrial-grade 25G SFP28 optical transceiver module that integrates an advanced 1310nm EML laser transmitter and an APD/TIA receiver to achieve reliable long-reach transmission over single-mode fiber (SMF) up to 40km, featuring a duplex LC/UPC connector interface and digital optical monitoring (DOM) capabilities all within a 1.8W maximum power envelope.

LINK-PP Part Number	LS-SM3125-40I	Vendor Name	LINK-PP
Form Factor	SFP28	Max Data Rate	25.78Gbps
Wavelength	1310nm	Max Cable Distance	40km
Connector	Duplex LC	Media	SMF
Transmitter Type	EML	Receiver Type	APD/TIA
Receiver Sensitivity	-19dBm	Operating Temperature Range	-40°C to +85°C
Protocols	SFF-8472, SFF-8432, SFF-8431	Warranty	5 Years

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Q: Does the DDM interface display the actual real-time optical reflection or return loss metrics? By V***r on 2026-03-08

A: No, the SFF-8472 digital diagnostics monitor real-time temperature, voltage, bias current, and received/transmitted optical power levels. By admin on 2026-03-09
Q: Do I need a special type of fiber cable to achieve the full 40km transmission distance? By W***r on 2025-10-25

A: You must use standard single-mode fiber (SMF) cables; multi-mode fiber (MMF) will not work for this long-reach optic. By admin on 2025-10-26
Q: Can this module survive inside sun-exposed field cabinets during extreme summer heatwaves? By U***e on 2025-08-03

A: Yes, its ruggedized industrial design ensures stable 25Gbps performance even when internal cabinet temperatures climb near the 85°C limit. By admin on 2025-08-04
Q: Will the optical receiver get damaged if my fiber run has a lot of sharp bends or splices? By X***k on 2025-07-02

A: Bends and splices increase link loss but won't damage the hardware, though too much signal loss can cause your 25G link to drop. By admin on 2025-07-03

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J***l

United States

Verified Purchase

5 .0

2026-04-02

Flawless 1310nm EML Performance! Very stable spectral alignment over long distances. No modal dispersion issues on our 32km link. Best 25GBASE-ER alternative on the market right now.

108 Helpful vote Comments

B***d

United States

Verified Purchase

5 .0

2026-03-23

Great optical transceiver budget alternative, but wish the pull-tab was slightly longer.

83 Helpful vote Comments

T***r

United States

Verified Purchase

5 .0

2026-02-11

APD receiver sensitivity is superb, zero frame loss on our 35km link.

64 Helpful vote Comments

O***d

United States

Verified Purchase

5 .0

2026-02-05

High-density cell site backhaul overhauls demand absolute link reliability, strict synchronization, and strict low power dissipation. We put these 25G SFP28 single-mode transceiver modules through exhaustive bit-error-rate testing over our rural macro tower feeds. The APD/TIA receiver sensitivity held a steady margin well clear of the -19dBm threshold with zero packet drops under peak traffic loads. They integrate flawlessly with our telecom routing hardware, making regional transport scaling much more affordable.

107 Helpful vote Comments

T***y

United States

Verified Purchase

4 .0

2026-01-19

The 1310nm EML laser transmitter gives an incredibly stable 25.78Gbps line rate. My only complaint is with the shipping updates: the tracking status didn't update for 3 days straight, making our procurement team quite anxious about meeting the data center deployment deadline. Everything arrived safely in the end.

35 Helpful vote Comments

E***e

United States

Verified Purchase

5 .0

2026-01-02

Upgraded our core from 10G SFP+ to 25G SFP28 using these 1310nm 40km SFP28 optical transceivers. Immediate bandwidth boost for our storage replication link. Super low power envelope under 1.8W too.

80 Helpful vote Comments

G***n

United States

Verified Purchase

5 .0

2025-12-15

Bulletproof SFF-8472 Compliance! Third-party optical modules usually make me nervous with DDM accuracy, but these LS-SM3125-40I modules show precise real-time diagnostic data (laser bias, voltage, temp) right inside our monitoring console. Outstanding quality.

96 Helpful vote Comments

E***m

United States

Verified Purchase

4 .0

2025-12-05

The industrial broad temperature version specs are spot on, and the DOM capabilities work beautifully with our telemetry scripts. Sadly, ordering during the holiday rush caused a 4-day shipping delay at the customs hub. The product itself deserves 5 stars, but the shipping logistics during peak season was a headache.

28 Helpful vote Comments

R***g

United States

Verified Purchase

5 .0

2025-11-16

Industrial broad temperature version is a lifesaver for our remote outdoor cabinets.

51 Helpful vote Comments

N***o

United States

Verified Purchase

5 .0

2025-11-01

Robust Performance on Long-Haul Campus Backbone Expansion! We deployed a dozen of these LS-SM3125-40I 25G SFP28 modules to link our core campus switches across a 35km single-mode fiber infrastructure. The 1310nm EML transmitter combined with the high-sensitivity APD receiver maintained an exceptionally clean signal with zero CRC errors during our 48-hour continuous stress test. The low power consumption of around 1.5W keeps our switch chassis running cool, proving it to be a highly reliable and budget-friendly optical module.

124 Helpful vote Comments

D***s

United States

Verified Purchase

5 .0

2025-10-19

We needed to link two campus sites roughly 28km apart over leased single-mode fiber (SMF). These 25GBASE-ER SFP28 optical modules pulled off full throughput with receiver sensitivity to spare. Will definitely keep buying from LINK-PP.

109 Helpful vote Comments

M***t

United States

Verified Purchase

5 .0

2025-09-05

We used these 25GBASE-ER modules to bridge two regional utility distribution nodes over 36km of dark single-mode fiber (SMF). The built-in 1310nm EML transmitter combined with the APD receiver delivered a rock-solid link without any bit errors. Absolute lifesaver for long-haul infrastructure upgrades!

63 Helpful vote Comments

A***h

United States

Verified Purchase

5 .0

2025-08-21

Best budget 25G SFP28 40km module for regional transport network upgrades.

50 Helpful vote Comments

S***a

United States

Verified Purchase

5 .0

2025-08-11

Green data center initiatives require us to strictly monitor the power envelope and thermal output of every single interface slot. While many third-party 25GBASE-ER optics transceivers run hot and draw excessive wattage, these modules stay well under the 1.8W max threshold even under maximum traffic loads. The low thermal dissipation prevents our high-density switch fans from constantly ramping up to full speed, reducing noise and power wear.

122 Helpful vote Comments

L***s

United States

Verified Purchase

5 .0

2025-07-21

Running 48 of these long-reach optics on a single leaf-switch can severely test your cooling setup, but these SFP28 modules stay well under the 1.8W max threshold. The power envelope is impressively low for a 40km transceiver.

48 Helpful vote Comments

F***d

United States

Verified Purchase

5 .0

2025-06-10

The 1310nm EML laser transmitter gives an incredibly sharp signal. Even with a couple of patch panels adding to the insertion loss on our long-haul SMF link, the receiver sensitivity kept the BER perfectly clean. High-five to the engineering team!

63 Helpful vote Comments

Z***s

United States

Verified Purchase

5 .0

2025-05-20

DOM capabilities work beautifully with our telemetry scripts. Quick shipping too!

77 Helpful vote Comments

P***r

United States

Verified Purchase

5 .0

2025-05-11

Real-world fiber plants are rarely perfect since multiple splices, older patch panels, and sharp bends constantly degrade the total optical budget. Despite these physical infrastructure challenges on our 35km leased dark fiber run, this transceiver maintained an exceptional link margin. The SFF-8472 compliant digital diagnostics allowed our engineering team to calibrate and track the TX power levels with absolute precision. It has completely eliminated the need for intermediate regeneration nodes, saving our enterprise a massive amount of operational budget.

140 Helpful vote Comments

C***y

United States

Verified Purchase

5 .0

2025-04-05

Tested 40km over single-mode fiber, got full speed with no errors!

96 Helpful vote Comments

H***m

United States

Verified Purchase

5 .0

2025-03-15

Top-Notch Industrial Backhaul Solution! Using these 25G modules for distributed outdoor cabinet aggregation nodes. The wide temperature tolerance makes them highly reliable for rural fiber-to-the-home (FTTH) distribution networks.

129 Helpful vote Comments

E***u

Turkey

Verified Purchase

5 .0

2024-07-06

Very nice sales to speak to and knowledgeable on the products they sell!

102 Helpful vote Comments

M***n

Japan

Verified Purchase

5 .0

2024-06-08

Item found quickly and in stock, great!

92 Helpful vote Comments

R***n

Poland

Verified Purchase

5 .0

2024-04-23

Everything is okay. I will definitely recommend this company to my friends.

72 Helpful vote Comments

J***e

Sweden

Verified Purchase

5 .0

2024-04-15

Link-pp is our preferred supplier for all our Fiber Optics and related items. The sales team, Miss Yoeng is such a lovely to work with especially during urgent times, she would go extra mile to ensure to meet our critical deadline. The product has been working as advertised and their pricing is one of the best.

45 Helpful vote Comments

G***a

United States

Verified Purchase

5 .0

2024-04-13

I'm very pleased with the speedy delivery and the great low price

53 Helpful vote Comments

M***B

Taiwan, Province of China

Verified Purchase

5 .0

2024-04-01

Delivered in 3 days. Competitive price. Fully satisfied.Thanks l-p.com!

17 Helpful vote Comments

a***d

Morocco

Verified Purchase

5 .0

2024-03-09

Friendly and super helpful customer service and Fast, efficient delivery of top quality modules.

28 Helpful vote Comments

x***n

India

Verified Purchase

5 .0

2023-09-20

Products always arrive ahead of scheduled delivery dates

36 Helpful vote Comments

Y***S

Belgium

Verified Purchase

5 .0

2023-08-28

Easy to use website simple layout. High recommended.

52 Helpful vote Comments

R***s

United States

Verified Purchase

5 .0

2023-07-24

Good service, efficient website. Will come back for more 1x1 Port SFP Cage.

27 Helpful vote Comments

B***o

Philippines

Verified Purchase

5 .0

2023-06-04

Great speed and great price for a quality product.

108 Helpful vote Comments

A***h

United States

Verified Purchase

5 .0

2023-05-26

I'm very pleased with the speedy delivery and the great low price

48 Helpful vote Comments

J***a

Indonesia

Verified Purchase

5 .0

2023-05-08

I am so glad I found this site! I have been looking for third-party transceivers for reasonable price for a long time! Believe me I will be back because shopping here is easy and affordable.

66 Helpful vote Comments

G***y

Brunei Darussalam

Verified Purchase

5 .0

2023-04-23

LINK-PP is a company with excellent sales people. They are technically oriented and know their products well. I have used them several times. Right product, on time, every time!

15 Helpful vote Comments

N***e

Monaco

Verified Purchase

5 .0

2023-04-06

The seller at l-p.com was wonderful to work with, the website is easy to use and made us comfortable choosing fiber modules online, and we would absolutely go again.

106 Helpful vote Comments

C***N

Germany

Verified Purchase

5 .0

2023-04-01

They communicate well, adjust my delivery costs when I make multiple orders and there prices are competitive.

118 Helpful vote Comments

M***n

United Kingdom

Verified Purchase

5 .0