Optical modules are the core components for the conversion of optical signals to electrical signals in optical communication systems. They are primarily composed of optical devices, control chips, PCBs (Printed Circuit Boards), auxiliary materials, and housings.
Optical devices, which include optical chips and optical component assemblies, account for over 70% of the cost of optical modules. Auxiliary materials, such as housings, pins, PCBs, and circuit chips, make up nearly 30% of the total cost of optical modules.
Structure of Optical Modules
Optical modules can be classified in various ways, including by packaging method, optical port rate, transmission distance, modulation format, whether they support wavelength division multiplexing, the type of optical fiber they are suitable for, the mode of optical interface operation, the type of optical chip, the type of connector interface, the method of use, and the operating temperature range.
| Packaging Methods | SFP/eSFP, SFP+, SFP28, QSFP+, CXP, CFP, QSFP28, QSFP-DD, OSFP, etc. |
| Optical Port Rate (b/s) | 10G, 25G, 50G, 100G, 400G, 800G, etc. |
| Transmission Distance | 100m, 10km, 20km, 40km, 80km, etc. |
| Modulation Format | NRZ (Non-Return-to-Zero), PAM4 (4-Level Pulse Amplitude Modulation), DP-QPSK/n-QAM (Differential Quadrature Phase Shift Keying/n-order Quadrature Amplitude Modulation), etc. |
| Support for Wavelength Division Multiplexing (WDM) | Gray Modules (Do not support WDM), Colored Modules (Support WDM) |
| Applicable Fiber Type | Single-mode optical modules (mostly used for long-distance transmission), Multi-mode optical modules (mostly used for short-distance transmission) |
| Optical Interface Working Mode | Dual-fiber bidirectional (Duplex), Single-fiber bidirectional (BiDi) |
| Optical Chip Type | Laser Chip: DFB (Distributed Feedback Laser, suitable for medium to long-distance transmission), EML (Electroabsorption Modulated Laser, suitable for long-distance transmission), VCSEL (Vertical-Cavity Surface-Emitting Laser, suitable for short-distance transmission) Detector Chip: PIN (Low noise, low sensitivity, low cost, suitable for medium to short-distance transmission), APD (Avalanche Photodiode, high noise, high sensitivity, high cost, suitable for long-distance transmission) |
| Connector Interface Type | FC (Ferrule Connector), SC (Square Connector), ST (Straight Tip), LC (Lucent Connector), MU (Miniature Unit), MTRJ (Mechanical Transfer Registered Jack) |
Usage Method | Hot-swappable (GBIC, SFP, XFP, XENPAK) and Non-hot-swappable (1*9, SFF) |
| Operating Temperature Range | Commercial Grade (0-70°C) Extended Temperature (-20 to 85°C) Industrial Grade (-40 to 85°C) |
| A | Encapsulation Type: Refers to the physical form or casing of the optical module. |
| B | Transmission Rate: Indicates the speed at which data is transmitted through the optical module, typically measured in gigabits per second (Gbps). |
| C | Transmission Distance Category:
|
| D | Transmission Distance: Specifies the distance over which the optical signal can be transmitted, measured in kilometers (km). |
| E | Optical Module Device Category:
|
| F | Optical Module Central Wavelength: The central wavelength of the light emitted or received by the optical module, measured in nanometers (nm). |
Optical modules are divided into the following categories based on application scenarios:
Ethernet optical modules: Mainly used in the data communication market, including data center networks, operators' metropolitan area networks, and backbone networks.
Fiber channel optical modules: Also used in the data communication market, for storage and high-performance computing networks.
Optical interconnect optical modules: Including AOCs (Active Optical Cables), mainly used in the data communication market for short-distance (<20m) interconnections within cabinets between servers and TOR (Top of Rack) switches.
CWDM (Coarse Wavelength Division Multiplexing) / DWDM (Dense Wavelength Division Multiplexing) optical modules: Used in various optical transmission equipment, including data center interconnections and operator networks.
Wireless fronthaul and wireless (mid-) backhaul: Mainly used in the telecommunications market, for wireless access networks within telecom operator networks.
Wired access optical modules: Mainly used in the telecommunications market, for point-to-multipoint optical modules in telecom operator networks.
In 2022, Ethernet optical modules ranked first in revenue share among all optical modules, accounting for 46%, and second in shipment volume, with a share of 31%, primarily used in Ethernet switches. CWDM/DWDM optical modules ranked second in revenue share, at 24%, but accounted for only 1% of shipments.
Data Source: LightCounting
The driving force of the optical module market has shifted from the early demand for backbone network construction and fiber-to-the-home to interconnection in data centers, with the data communication market now surpassing the telecommunications market.
Ethernet optical modules account for nearly half of the revenue in the optical module market, with a market space exceeding ten billion US dollars. Ethernet optical modules follow the IEEE 802.3 standard and are mainly used in data centers and campus networks. High-speed Ethernet optical modules (200G, 400G, and 800G) are the core drivers of demand growth for Ethernet optical modules.
Data Source: LightCounting
According to the latest report from LightCounting, it is expected that by 2026, the Ethernet optical module market will reach $8.851 billion, accounting for about 52% of the global optical module market size, with a compound annual growth rate of 11.7% from 2022 to 2026.
Multiple manufacturers have already launched 800G optical modules, including Intel, II-VI, Zhongji Xu Chuang, New Yisheng, Guangxun Technology, Huazhong University of Science and Technology, Source Photonics, Cambridge Technology, and Hengtong Optoelectronics.
DR8 and 2*FR4 are being promoted as mainstream solutions by more cloud computing vendors, mainly due to their smooth evolution or compatibility with the currently deployed 400G modules. Meanwhile, 800G DR8 and DR4 are considered the most advantageous solutions for silicon photonics and have become key products for silicon photonics manufacturers.
CPO, or Co-Packaged Optics, involves bringing optical modules closer to the switching chips, reducing the wiring distance between the chips and modules, and gradually replacing pluggable optical modules. The ultimate goal is to co-package the switching chips (or XPU) ASICs and optical/electric engines (optical transceivers) on the same substrate, with the engines as close to the ASICs as possible. This minimizes high-speed electrical channel loss and impedance discontinuity, allowing for the use of faster, lower-power external I/O drivers.
Evolution of Optical Modules
With the increase in electrical port rates to 112G, the loss of high-speed signals in PCB transmission increases, posing challenges to the design complexity of PCBs and the cost of materials. Additionally, more Retimer chips need to be added to the high-speed wiring between pluggable optical modules and switching chips, which will significantly increase the overall operating power consumption of the system. To overcome these issues, CPO is gradually becoming a consensus.
Silicon photonics technology is based on standard silicon manufacturing on a silicon substrate material. It leverages the extendable characteristics of semiconductor wafer materials and applies processes such as CMOS to the manufacturing of integrated optoelectronic devices. Its physical architecture consists of a silicon substrate laser, a silicon substrate optoelectronic integrated chip, and auxiliary materials such as optical fibers.
One of the challenges of silicon photonics technology is the integration of lasers and modulators, PD (Photodetector), and various passive devices. Currently, the relevant technologies mainly include discrete lasers, hybrid integration, heterogeneous integration, and monolithic integration.
Silicon Photonics Module Market Forecast
Data Source: Yole
Disclaimer: The content of the article is compiled from publicly available materials on the internet, with the copyright belonging to the original author's platform. It is for information sharing only and will be removed if there is any infringement.
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