1000BASE-SX optical Ethernet specification

Overview

The 1000BASE-SX PTMs can be used for Gigabit Ethernet service over Multi-Mode Fiber (MMF).

System specifications

The following are the 1000BASE-SX system specifications:

• Optical Line Rate: 1.25 Gb/s (±100 ppm)

• Optical Line Coding: 8B/10B

• Performance: Short-reach

GbE compliance

The PTM optics are compliant with GbE specifications.

Operating range

The table below shows the operating range for the 1000BASE-SX optical Ethernet interface. A 1000BASE-SX compliant transceiver supports both 50 μm and 62.5 μm fiber media types. A transceiver that exceeds the operational range requirement while meeting all other optical specifications is considered compliant (for example, a 50 μm solution operating at 600 m meets the minimum range requirement of 2 to 550 m).

Table 10-36: 1000BASE-SX operating range over each optical fiber type

Fiber Type	Modal Bandwidth @ 850 nm (minimum overfilled launch)	Minimum Range
62.5 μm MMF	160 MHz-km	2 to 220 m
	200 MHz-km	2 to 275 m
50 μm MMF	400 MHz-km	2 to 500 m
	500 MHz-km	2 to 550 m
10 μm SMF	Not supported	Not supported

Transmitter specifications

The 1000BASE-SX optical transmitter meets the specifications defined in IEEE 802.3. The table below shows some of the 1000BASE-SX optical transmitter specifications. Measurement techniques are defined in IEEE 802.3, Section 38, Clause 6.

Table 10-37: 1000BASE-SX transmit specifications

Description	1000BASE-SX
Transmitter type	Shortwave Laser
Signaling speed (range)	1.25 GBd (±100 ppm)
Wavelength (λ, range)	770 to 860 nm
Trise/Tfall (max; 20%−80%; l > 830 nm)	0.26 ns
Trise/Tfall (max; 20%-80%; l ≤ 830 nm)	0.21 ns
Maximum RMS Spectral Width (σ)	0.85 nm
Average launch power (max) 1	0 dBm
Average launch power (min)	−9.5 dBm
Average launch power of OFF transmitter (max) 2	−30 dBm
Extinction ratio (min)	9 dB
RIN (max)	−117 dB/Hz
Coupled Power Ratio (CPR) (min) 3	9 dB < CPR

Notes:

1. The 1000BASE-SX launch power must be the lesser of the class 1 safety limit as defined by IEEE 802.3, Section 38, Clause 7.2 or the average receiver power (maximum) defined by Table 10-38, 1000BASE-SX receive specifications.

2. Examples of an OFF transmitter are as follows: no power supplied to the optical module, laser shutdown for safety conditions, and activation of a "transmit disable" or other optional module laser shut-down conditions.

3. Radial overfilled launches (described in IEEE 802.3, Section 38A, Clause 2) should be avoided even if they meet CPR ranges.

Receiver specifications

The 1000BASE-SX optical receiver meets the specifications defined in IEEE802.3, Section 38.3.2. The table below shows some of the 1000BASE-SX optical receiver specifications. Measurement techniques are defined in IEEE802.3, Section 38, Clause 6.

Table 10-38: 1000BASE-SX receive specifications

Description	1000BASE-SX
	62.5 μm MMF	50 μm MMF
Signaling speed (range)	1.25 GBd (±100 ppm)	1.25 GBd (±100 ppm)
Wavelength (range)	770 to 860 nm	770 to 860 nm
Average receive power (max)	0 dBm	0 dBm
Receive sensitivity	−17.0 dBm	−17.0 dBm
Return loss (min) 1	12.0 dB	12.0 dB
Receive electrical 3 dB upper cutoff frequency (max)	1500 MHz	1500 MHz

Notes:

1. Refer to the IEEE802.3 standards for more information about return loss (min).

Link budgets

The worst-case power budget and link penalties for a 1000BASE-SX channel are shown in the table below.

Table 10-39: 1000BASE-SX link budgets and penalties

Parameter	1000BASE-SX
	62.5 μm MMF		50 μm MMF
Modal bandwidth as measured at 850 nm (minimum, overfilled launch)	160 MHz-km	200 MHz-km	400MHz-km	500 MHz-km
Link power budget	7.5 dB	7.5 dB	7.5 dB	7.5 dB
Operating distance	220 m	275 m	500 m	550 m
Channel insertion loss 1	2.38 dB	2.60 dB	3.37 dB	3.56 dB
Link power penalties 1	4.27 dB	4.29 dB	4.07 dB	3.57 dB
Unallocated margin in link power budget	0.84 dB	0.60 dB	0.05 dB	0.37 dB

Notes:

1. A wavelength of 830 nm is used to calculate the channel insertion loss, link power penalties, and unallocated margin.