100G QSFP28 Single Wavelength

A QSFP28 100G single-wavelength module delivers 100 Gbps over one optical lambda using PAM4 modulation, instead of spreading traffic across 4 wavelengths like CWDM4/LR4.

This design reduces power, cost, and optical complexity while keeping the familiar QSFP28 form factor.

🔹 How 100G Single-Lambda Works in QSFP28

Instead of:

• 4 × 25G NRZ on 4 wavelengths (CWDM4)

It uses:

• 1 wavelength

• PAM4 modulation

• On-board DSP

• Single-mode fiber (SMF)

This allows 100G transmission using just a duplex fiber pair.

🔹 Main Variants

🔸 100GBASE-DR

• Distance: up to 500m

• Fiber: SMF

• Application: data center interconnect

🔸 100GBASE-FR

• Distance: up to 2 km

• Fiber: SMF

• Application: campus / aggregation

🔸 100GBASE-LR (Single-Lambda version)

• Distance: up to 10 km

• Fiber: SMF

• Application: metro / enterprise edge

Defined under standards from the IEEE (802.3cd / 802.3cu).

🔹 Internal Architecture

Typical QSFP28 single-lambda module includes:

• EML or Silicon Photonics laser (1310nm)

• PAM4 DSP

• Driver IC

• TIA (Transimpedance Amplifier)

• Microcontroller

• LC duplex interface

Because only one wavelength is used, no CWDM mux/demux array is required, reducing cost and power.

🔹 Advantages vs 100G CWDM4

Feature	Single-Lambda	CWDM4
Wavelengths	1	4
Power	Lower	Higher
BOM cost	Lower	Higher
Optical complexity	Simpler	More complex
Manufacturing yield	Better	Lower

🔹 Applications

• Hyperscale data centers

• 5G fronthaul/backhaul

• Metro aggregation

• Enterprise backbone

GigOptics - Your Trusted Source for Optics

At GigOptics, we offer a wide range of 100G QSFP28 optical transceivers; all tested to ensure quality and reliability. For more information, contact us at info@gigoptics.com.