IEC 62803-2:2024

Transmitting and receiving equipment for radiocommunication - Frequency response of optical-to-electric conversion device in high-frequency radio-over-fibre systems - Part 2: Measurement method of common-mode rejection ratio of optical coherent detection device for radio-over-fibre transmitter

IEC 62803-2:2024 provides the measurement method of the common-mode rejection ratio of optical coherent detection devices in high-speed RoF systems, as well as in high-speed optical signal transmission systems. In addition, the method is also effective for the estimation of the detailed frequency response of the common-mode rejection ratios and O/E conversion efficiency. The method applies for the following:
- frequency range: 1 GHz to 110 GHz;
- wavelength band: 0,8 µm to 2,0 µm.
The use of optical coherent detection devices for high-speed RoF system is shown in Annex A as an example.

General Information

• Status: Published
• Publication Date: 22-Aug-2024
• ICS: 33.060.20 - Receiving and transmitting equipment
• Technical Committee: TC 103 - Transmitting and receiving equipment for radiocommunication
• Drafting Committee: WG 6 - TC 103/WG 6
• Current Stage: PPUB - Publication issued
• Start Date: 23-Aug-2024
• Completion Date: 20-Sep-2024

Overview

IEC 62803-2:2024 specifies a standardized measurement method for the common‑mode rejection ratio (CMRR) of optical coherent detection devices used in high‑speed radio‑over‑fibre (RoF) and high‑speed optical signal transmission systems. The standard supports detailed estimation of frequency response for CMRR and optical-to-electric (O/E) conversion efficiency across microwave and millimetre‑wave bands. An informative Annex A illustrates application to RoF transmitters.

Key scope points:

• Frequency range: 1 GHz to 110 GHz
• Wavelength band: 0.8 µm to 2.0 µm
• Applies to optical coherent detection devices comprising a 90° optical hybrid and balanced photodiodes

Key topics and technical requirements

• Definition of CMRR: Ratio between differential-signal power and common‑mode signal power for coherent optical receivers.
• Device description: Configuration and component parts of optical coherent detection devices (90° hybrid, balanced photodiode, pigtails, RF ports).
• Measurement principle: Circuit diagrams, mathematical expressions, and procedures to measure CMRR and frequency response.
• Measurement conditions: Environmental and equipment warm‑up requirements to ensure repeatable, accurate results.
• Sampling and quality control: Guidance on sampling frequency and quality control for production or design validation.
• Frequency and wavelength applicability: Explicit constraints (1–110 GHz, 0.8–2.0 µm) to guide test setups and instrumentation.
• Informative examples: Annex A shows practical application of coherent detection in millimetre‑wave RoF front‑ends.

Applications and practical value

• Validates optical coherent detection performance for:
  • Radio‑over‑fibre (RoF) links carrying microwave and millimetre‑wave signals
  • Coherent optical transport systems where O/E conversion linearity and noise suppression are critical
• Enables accurate assessment of noise suppression, receiver imbalance, and frequency‑dependent degradation affecting system-level metrics (EVM, SNR).
• Useful for:
  • Component manufacturers (90° hybrids, balanced photodiodes) for design verification
  • Test laboratories and R&D teams performing O/E characterization and calibration
  • System integrators and telecom/radar equipment vendors specifying RoF front‑ends
  • Certification and quality assurance workflows needing standardized measurement procedures

Who should use this standard

• Optical receiver designers and manufacturers
• Radio‑over‑fibre system engineers and test houses
• Telecom and radar system integrators deploying high‑frequency RoF links
• Standards and compliance teams preparing product specifications or acceptance tests

Related standards

• IEC 62803 series - broader series addressing frequency response of optical‑to‑electric conversion devices in high‑frequency RoF systems (check IEC webstore for other parts).

Keywords: IEC 62803-2, common‑mode rejection ratio, CMRR measurement, optical coherent detection, radio‑over‑fibre, RoF, O/E conversion, frequency response, 1–110 GHz, 0.8–2.0 µm.

Standards Content (Sample)

IEC 62803-2 ®
Edition 1.0 2024-08
INTERNATIONAL
STANDARD
Transmitting and receiving equipment for radiocommunication – Frequency
response of optical-to-electric conversion device in high-frequency radio-over-
fibre systems –
Part 2: Measurement method of common-mode rejection ratio of optical
coherent detection device for radio-over-fibre transmitter
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IEC 62803-2 ®
Edition 1.0 2024-08
INTERNATIONAL
STANDARD
Transmitting and receiving equipment for radiocommunication – Frequency
response of optical-to-electric conversion device in high-frequency radio-over-
fibre systems –
Part 2: Measurement method of common-mode rejection ratio of optical
coherent detection device for radio-over-fibre transmitter
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.060.20 ISBN 978-2-8322-9567-0
– 2 – IEC 62803-2:2024 © IEC 2024
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviated terms . 6
3.1 Terms and definitions . 6
3.2 Abbreviated terms . 7
4 Optical coherent detection device . 7
4.1 General . 7
4.1.1 Configuration . 7
4.1.2 Component parts . 7
4.1.3 Structure . 7
4.2 Optical coherent detection device . 8
4.2.1 General . 8
4.2.2 Material of 90° optical hybrid . 8
4.2.3 Material of balanced photodiode . 8
5 Sampling for quality control . 8
5.1 Sampling. 8
5.2 Sampling frequency . 8
6 Measurement method of common-mode rejection ratio . 8
6.1 Circuit diagram . 8
6.2 Circuit description and requirements . 9
6.3 Measurement conditions . 10
6.3.1 Temperature and environment . 10
6.3.2 Warming-up of measurement equipment . 10
6.4 Principle of measurement method . 10
6.4.1 General . 10
6.4.2 Mathematical expressions of basic measurement principle . 10
6.4.3 Principle of measurement of common-mode rejection ratio . 12
6.5 Measurement procedure . 13
Annex A (informative) Application of optical coherent detection device to RF signal
transmission . 14
A.1 Purpose . 14
A.2 Diagrams . 14
Bibliography . 15

Figure 1 – Optical coherent detection device . 8
Figure 2 – Circuit diagram . 9
Figure 3 – Schematic illustration of the electric power spectra of the signal measured
by the electrical spectrum analyser . 13
Figure A.1 – Example of block diagram of a radar radio frontend using a coherent
receiver . 14

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TRANSMITTING AND RECEIVING EQUIPMENT FOR
RADIOCOMMUNICATION – FREQUENCY RESPONSE OF
OPTICAL‑TO‑ELECTRIC CONVERSION DEVICE IN
HIGH-FREQUENCY RADIO-OVER-FIBRE SYSTEMS –

Part 2: Measurement method of common-mode rejection ratio of optical
coherent detection device for radio-over-fibre transmitter

FOREWORD
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IEC 62803-2 has been prepared by IEC technical committee 103: Transmitting and receiving
equipment for radiocommunication. It is an International Standard.

– 4 – IEC 62803-2:2024 © IEC 2024
The text of this International Standard is based on the following documents:
Draft Report on voting
103/269/FDIS 103/274/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
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A list of all parts in the IEC 62803 series, published under the general title Transmitting and
receiving equipment for radiocommunication – Frequency response of optical‑to‑electric
conversion device in high-frequency radio-over-fibre systems can be found on the IEC website.
Future documents in this series will carry the new general title as cited above. Titles of existing
documents in this series will be updated at the time of the next edition.
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INTRODUCTION
A variety of photonic devices operated in microwave and millimetre-wave bands are useful for
an optical fibre transport system as well as wireless communication and broadcasting systems.
An optical-to-electric conversion device including an optical receiver plays as an interface,
which converts an optical signal into an electrical signal directly.
Microwave and millimetre-wave radio-over-fibre (RoF) systems are comprised mainly of two
parts: an RF to photonic converter (E/O) and a photonic to RF converter (O/E). Radio waves
are converted into an optical signal at the E/O, and the signal is transferred through the optical
fibre, and then the radio waves are regenerated at the O/E.
A variety of photonic devices which carry microwave and millimeter-wave signals at subcarrier
frequencies are used for high-frequency RoF systems. In high-frequency RoF systems such as
millimetre-wave band radio signal transfer systems, the specifications of conversion efficiency
and its frequency response have been important technical parameters, and therefore, the
IEC 62803 series has been developed. Nowadays, the coherent optical fibre network system is
used widely, namely in core and metro networks with a capacity greater than 100 Gbit/s/ch.
Finally, cost and performance have improved. In this coherent optical fibre network system, an
optical coherent detection device, which is comprised of an optical 90° hybrid coupler and
balanced photodetectors, provides an IQ separation in an optical domain for easy digital signal
processing. This detection device can be useful not only for the coherent optical signal transport
but also for a millimeter-wave RoF system with high signal quality. To achieve a high signal
quality, which means a good suppression of noises, a common-mode rejection ratio is a key
parameter of the optical coherent detection. This document has been developed to provide to
the industry a measurement method of a coherent optical detection device for evaluating the
specifications to be used in high-frequency RoF systems, as well as in an optical coherent
transport system. This document defines the measurement method of a common-mode rejection
ratio, which has a significant impact on the performance of RoF systems.

– 6 – IEC 62803-2:2024 © IEC 2024
TRANSMITTING AND RECEIVING EQUIPMENT FOR
RADIOCOMMUNICATION – FREQUENCY RESPONSE OF
OPTICAL‑TO‑ELECTRIC CONVERSION DEVICE IN
HIGH-FREQUENCY RADIO-OVER-FIBRE SYSTEMS –

Part 2: Measurement method of common-mo
...