Table of Contents - G Suppl. 39 (03/2025) - Optical system design and engineering considerations

1	Scope
2	References
3	Definitions
	3.1	Terms defined elsewhere
	3.2	Terms defined in this Recommendation
4	Abbreviations and acronyms
5	Definition of spectral bands
	5.1	General considerations
	5.2	Allocation of spectral bands for single-mode fibre systems
	5.3	Bands for multimode fibre systems
6	Parameters of system elements
	6.1	Line coding
	6.2	Transmitters
	6.3	Optical amplifiers
	6.4	Optical path
	6.5	Receivers
7	Line coding considerations
	7.1	Overview of various line coding schemes
	7.2	Return to zero (RZ) implementation
	7.3	ODB and RZ-AMI line coding format
	7.4	Pulse amplitude modulation
	7.5	Differential phase shift keying (DPSK) modulation implementations
	7.6	Differential quadrature phase shift keying (DQPSK) implementation
	7.7	DP-QPSK (PM-QPSK) implementation
	7.8	Optical orthogonal frequency division multiplexing (O-OFDM)
	7.9	Nyquist WDM
	7.10	Polarization division multiplexing binary phase shift keying (PDM-BPSK) implementation
	7.11	Quadrature amplitude modulation (QAM) implementation
	7.12	System impairment considerations
	7.13	Multi-dimensional modulation formats
	7.14	Probabilistic constellation shaping
8	Optical network topology
	8.1	Topological structures
9	"Worst-case" system design
	9.1	Power budget concatenation
	9.2	Chromatic dispersion
	9.3	Polarization mode dispersion
	Page
	9.4	BER and Q factor
	9.5	Noise concatenation
	9.6	Optical crosstalk
	9.7	Concatenation of non-linear effects – Computational approach
10	Statistical system design
	10.1	Generic methodology
	10.2	Statistical design of loss
	10.3	Statistical design of chromatic dispersion
	10.4	Statistical design of polarization mode dispersion
11	Forward error correction (FEC)
	11.1	In-band FEC in SDH systems
	11.2	Out-of-band FEC in optical transport networks (OTNs)
	11.3	Coding gain and net coding gain (NCG)
	11.4	HD-FEC and SD-FEC applications
	11.5	Statistical assumption for coding gain and NCG
	11.6	Candidates for parameter relaxation
	11.7	Candidates for improvement of system characteristics
12	Physical layer transverse and longitudinal compatibility
	12.1	Physical layer transverse compatibility
	12.2	Physical layer longitudinal compatibility
	12.3	Joint engineering
13	Switched optical network design considerations
14	Best practices for optical power safety
	14.1	Viewing
	14.2	Fibre ends
	14.3	Ribbon fibres
	14.4	Test cords
	14.5	Fibre bends
	14.6	Board extenders
	14.7	Maintenance
	14.8	Test equipment
	14.9	Modification
	14.10	Key control
	14.11	Labels
	14.12	Signs
	14.13	Alarms
	14.14	Raman amplified systems
Appendix I – Pulse broadening due to chromatic dispersion
	I.1	Purpose
	Page
	I.2	General published result
	I.3	Change of notation
	I.4	Simplification for a particular case
	I.5	Pulse broadening related to bit rate
	I.6	Value of the shape factor
	I.7	General result and practical units
Bibliography