Ascent Communication Technology

400G QSFP-DD LR4 CWDM 10 km

Ascent’s QSFP-DD-LR4-10 is a 400Gb/s Quad Small Form Factor Pluggable-double density (QSFP-DD) optical module designed for 10 km optical communication applications. The module converts 8 channels of 50Gb/s (PAM4) electrical input data to 4 channels of CWDM optical signals, and multiplexes them into a single channel for 400 Gb/s optical transmission. Reversely, on the receiver side, the module optically de-multiplexes a 400 Gb/s optical input into 4 channels of CWDM optical signals, and converts them to 8 channels of 50 Gb/s (PAM4) electrical output data.

• Compliant with 100G Lambda MSA: 400GBASE-LR4-10 optical interface

• Compliant with IEEE 802.3bs standard: 400GAUI-8 electrical interface

• Compliant with QSFP-DD MSA HW Rev 5.1 type 2 housing with duplex LC connector

• Compliant with QSFP-DD CMIS Rev 4.0

• Operating distance at engineering link of up to 10 km

• Maximum power consumption 10 W

• Case operating temperature 0 °C to +70 °C

• Two wire serial Interface with digital diagnostic monitoring

• Complies with EU Directive 2011/65/EU (RoHS compliant)

• Class 1 Laser

Absolute Maximum Ratings

Parameter	Symbol	Min.	Max.	Unit	Note
Storage Temperature	T_S	‑40	85	°C
Supply Voltage	V_CC	‑0.5	3.6	V
Relative Humidity (non‑condensing)	RH	5	95	%	Non‑condensing
Data Input Voltage Differential	lV_DIP‑V_DINl	‑	1	V
Control Input Voltage	V_I	‑0.3	V_CC+0.5	V
Control Output Voltage	V_O	‑20	20	V

Recommended Operating Conditions

Parameter	Symbol	Min.	Typ.	Max.	Unit	Note
Operating Case Temperature	T_OPR	0	‑	70	°C
Power Supply Voltage	V_CC	3.135	3.3	3.465	V
Instantaneous Peak Current at Hot Plug	I_{CC_IP}	‑	‑	4000	mA
Sustained Peak Current at Hot Plug	I_{CC_SP}	‑	‑	3300	mA
Maximum Power Dissipation	P_D	‑	‑	10	W
Maximum Power Dissipation, Low Power Mode	P_DLP	‑	‑	1.5	W
Signaling Rate per Lane	SRL	‑	53.125	‑	GBd	1
Two Wire Serial Interface Clock Rate	‑	‑	‑	400	kHz
Power Supply Noise Tolerance	‑	‑	‑	66	mV	2
Rx Differential Data Output Load	‑	‑	100	‑	Ω
Operating Distance	‑	2	‑	10000	m

Notes:

1. PAM4

2. 10 Hz to 10 MHz

Electrical Specification High Speed Signal (Compliant with IEEE 802.3bs 400GAUI‑8)

Parameter	Symbol	Min.	Typ.	Max.	Unit	Notes
Receiver (Module Output)
AC Common‑Mode Output Voltage (RMS)		‑	‑	17.5	mV
Differential Output Voltage		‑	‑	900	mV
Near‑End Eye Height, Differential		70	‑	‑	mV
Far‑End Eye Height, Differential		30	‑	‑	mV
Far End Pre‑Cursor Ratio		‑4.5	‑	2.5	%
Differential Termination Mismatch		‑	‑	10	%
Transition Time (Min., 20% To 80%)		9.5	‑	‑	ps
DC Common Mode Voltage		‑350	‑	2850	mV
Transmitter (Module Input)
Differential pk‑pk Input Voltage Tolerance		900	‑	‑	mV
Differential Termination Mismatch		‑	‑	10	%
Single‑Ended Voltage Tolerance Range		‑0.4	‑	3.3	V
DC Common Mode Voltage		‑350	‑	2850	mV

Electrical Specification Low Speed Signal (compliant with QSFP‑DD HW Rev 5.0)

Parameter	Symbol	Min.	Max.	Unit	Note
Module Output SCL and SDA	V_OL	0	0.4	V
Module Input SCL and SDA	V_IL	‑0.3	V_CC*0.3	V
	V_IH	V_CC*0.7	V_CC+0.5	V
InitMode, ResetL, and ModSelL	V_IL	‑0.3	0.8	V
	V_IH	2	V_CC+0.3	V
IntL	V_OL	0	0.4	V
	V_OH	V_CC‑0.5	V_CC+0.3	V

Optical Characteristics

Parameter	Symbol	Min.	Typ.	Max.	Unit	Note
Transmitter
Wavelength L0	λ_C0	1264.5	1271	1277.5	nm
Wavelength L1	λ_C1	1284.5	1291	1297.5	nm
Wavelength L2	λ_C2	1304.5	1311	1317.5	nm
Wavelength L3	λ_C3	1324.5	1331	1337.5	nm
Side Mode Suppression Ratio	SMSR	30	‑	‑	dB
Average Launch Power, each Lane	AOPL	‑3.3	‑	3.5	dBm	1
Outer Optical Modulation Amplitude (OMA_outer), each Lane	T_OMA	‑0.3	‑	3.7	dBm
Outer Optical Modulation Amplitude (OMA_outer), each lane: for TDECQ<1.4dB for 1.4≤TDECQ≤3.4dB	T_OMA	0.3 ‑1.1+ TDECQ			dBm dBm
Difference in Launch Power between any Two Lanes (OMA_outer)	DP	‑	‑	4	dB
Transmitter and Dispersion Eye Closure for PAM4 (TDECQ), each Lane	TDECQ	‑	‑	3.9	dB
Transmitter Eye Closure for PAM4 (TECQ)	TECQ	‑	‑	3.9
\| TDECQ ‑ TECQ \|	‑	‑	‑	2.5	dB
Over/Under‑Shoot	‑	‑	‑	25	%
Transmitter Peak‑to‑Peak Power	‑	‑	‑	5.2	dBm
Average Launch Power of OFF Transmitter, each Lane	T_OFF	‑	‑	‑16	dBm
Extinction Ratio, each lane	ER	3.5	‑	‑	dB
Transmitter Transition Time	TT	‑	‑	17	ps
RIN_15.6OMA	RIN	‑	‑	‑136	dB/Hz
Optical Return Loss Tolerance	ORL	‑	‑	15.6	dB
Transmitter Reflectance	T_R	‑	‑	‑26	dB
Receiver
Wavelength L0	λ_C0	1264.5	1271	1277.5	nm
Wavelength L1	λ_C1	1284.5	1291	1297.5	nm
Wavelength L2	λ_C2	1304.5	1311	1317.5	nm
Wavelength L3	λ_C3	1324.5	1331	1337.5	nm
Damage Threshold, each Lane	AOP_D	6.1	‑	‑	dBm
Average Receive Power, each Lane	AOP_R	‑9	‑	5.1	dBm	2
Receive Power (OMA_outer), each Lane	OMA_R	‑	‑	4.4	dBm
Difference in Receive Power between any Two Lanes (Oma_outer)	DR	‑	‑	4.3	dB
Receiver Reflectance	RR	‑	‑	‑26	dB
Receiver Sensitivity (OMAouter), each lane: for TECQ <1.4dB for 1.4≤TECQ≤3.4dB	S_OMA	‑	‑	‑6.8‑8.2+TECQ	dBm dBm
Stressed Receiver Sensitivity (OMA_outer), each lane	SRS	‑	‑	‑4.3	dBm
Conditions of Stressed Receiver Sensitivity Test
Stressed Eye Closure for PAM4 (SECQ)	‑	‑	3.9	‑	dB
OMA_outer of each Aggressor Lane	‑	‑	‑0.4	‑	dBm

Notes:

1. Average launch power, each lane (min) is informative and not the principal indicator of signal strength.

2. Average receive power, each lane (min) is informative and not the principal indicator of signal strength.

Digital Diagnostics

Parameter	Range	Accuracy	Unit	Calibration
Temperature	0 to 70	±3	°C	Internal
Voltage	0 to V_CC	0.1	V	Internal
Tx Bias Current (each Lane)	0 to 100	10%	mA	Internal
Tx Output Power (each Lane)	‑2.7 to +5.1	±3	dB	Internal
Rx Receive Power (each Lane)	‑9 to +5.1	±3	dB	Internal