Ascent Communication Technology

100G QSFP28 LR4 1310 nm 10 km

Ascent’s 100G QSFP28 LR4 Optical Transceiver integrates receiver and transmitter path on one module. In the transmit side, four lanes of serial data streams are recovered, retimed, and passed to four laser drivers. The laser drivers control 4 × Distributed Feedback Laser (DFB) with center wavelengths of 1296 nm, 1300 nm, 1305 nm, and 1309 nm. The optical signals are multiplexed to a single-mode fiber through an industry standard LC connector. In the receive side, the four lanes of optical data streams are optically de-multiplexed by the integrated optical de-multiplexer. Each data stream is recovered by a PIN photo-detector and trans-impedance amplifier, retimed. This module features a hot-pluggable electrical interface, low power consumption and MDIO management interface.

• Compliant with 100GBASE‑LR4

• Support line rates from 103.125 Gbps to 111.81 Gbps

• Integrated LAN WDM TOSA / ROSA for up to 10 km reach over SMF

• Digital Diagnostics Monitoring Interface

• Duplex LC optical receptacle

• No external reference clock

• Electrically hot-pluggable

• Compliant with QSFP28 MSA with LC connector

• Power dissipation < 3.5 W

Absolute Maximum Ratings

Parameter	Symbol	Min.	Typ.	Max.	Unit	Note
Storage Temperature	Ts	‑40	‑	85	°C
Relative Humidity	RH	5	‑	95	%
Power Supply Voltage	VCC	‑0.3	‑	4	V
Signal Input Voltage		Vcc‑0.3	‑	Vcc+0.3	V

Recommended Operating Conditions

Parameter	Symbol	Min.	Typ.	Max.	Unit	Note
Case Operating Temperature	Tcase	0	‑	70	°C	Without air flow
Power Supply Voltage	VCC	3.13	3.3	3.47	V
Power Supply Current	ICC	‑		1060	mA
Data Rate	BR		25.78125		Gbps	Each channel
Transmission Distance	TD		‑	10	km
Coupled fiber	Single‑mode fiber					9/125 µm SMF

Optical Characteristics

Parameter	Symbol	Min	Typ	Max	Unit	Note
Transmitter
Wavelength Assignment	λ0	1294.53	1295.56	1296.59	nm
	λ1	1299.02	1300.05	1301.09	nm
	λ2	1303.54	1304.58	1305.63	nm
	λ3	1308.09	1309.14	1310.19	nm
Total Output Power	POUT			10.5	dBm
Average Launch Power per Lane		‑4.3		4.5	dBm
Spectral Width (‑20 dB)	σ			1	nm
SMSR		30			dB
Optical Extinction Ratio	ER	4			dB
Average launch Power off per lane	Poff			‑30	dBm
RIN	RIN			‑128	dB/Hz
Output Eye Mask Definition {X1, X2, X3, Y1, Y2, Y3}	{0.25, 0.4, 0.45, 0.25, 0.28, 0.4}
Receiver
Rx Sensitivity per lane	R_SENS			‑10.6	dBm	1
LOS De‑Assert	LOSD	‑30			dBm
LOS Assert	LOSA			‑12	dBm
Input Saturation Power (Overload)	Psat			4.5	dBm
Receiver Reflectance	Rr			‑26	dB

Notes:

1. Measured with a PRBS 2³¹‑1 test pattern, @ 25.78Gb/s, BER<10^‑12.

Electrical Characteristics

Parameter	Symbol	Min	Typ	Max	Unit	Note
Supply Voltage	Vcc	3.13	3.3	3.47	V
Supply Current	Icc			1060	mA
Transmitter
Input Differential Impedance	Rin		100		Ω	1
Differential Data Input Swing	Vin, pp	180		1000	mV
Transmit Disable Voltage	VD	Vcc‑1.3		Vcc	V
Transmit Enable Voltage	VEN	Vee		Vee+0.8	V	2
Receiver
Differential Data Output Swing	Vout, pp	300		850	mV	3
LOS Fault	VLOS_fault	Vcc‑1.3		Vcc_HOST	V	4
LOS Normal	VLOS_norm	Vee		Vee+0.8	V	4