There is still significant development potential in fiber optic communication technology, and there will be considerable demand and market in the future. Mainly, the development of Fiber-to-the-Home (FTTH), optical switching, and integrated optoelectronic devices will see significant growth. This discussion primarily focuses on the trends and market of fiber optic communication.
Trends in Fiber Optic Communication
1.Development of Fiber-to-the-Home (FTTH)
FTTH provides users with abundant bandwidth, making it an ideal access method crucial for realizing an information society. However, it requires extensive promotion and construction. The fiber optic needed for FTTH may be two to three times the existing laid fiber. In the past, high costs and lack of broadband video services and content delayed the adoption of FTTH. However, recent advancements in optoelectronic devices and reductions in the prices of optical transceivers and fibers, along with improvements in broadband content, have accelerated the practical implementation of FTTH.
Developed countries have varying perspectives on FTTH. For instance, AT&T in the United States considered the FTTH market to be small and projected it to take 20-50 years to materialize. In contrast, Verizon and Sprint in the US are more proactive and plan to adopt FTTH network upgrades within 10-12 years. Japan’s NTT was an early adopter of FTTH and currently has nearly 2 million users. Currently, FTTH in China is in the trial stage.
ADSL technology, widely used for broadband services, still holds certain advantages over FTTH. In comparison, ADSL is cheaper, utilizes existing copper wire networks for simpler construction, and can meet the demands of current video transmissions ranging from 1Mbps to 500kbps. However, for upcoming broadband services such as online education, telecommuting, teleconferencing, online gaming, and telemedicine, as well as asymmetric services like HDTV, ADSL is inadequate. HDTV, in particular, requires high transmission rates, which ADSL struggles to provide. Thus, HDTV is seen as a major driver for FTTH adoption.
FTTH solutions typically fall into two categories: Point-to-Point (P2P) and Passive Optical Network (PON).
P2P Advantages include independent transmission for each user, flexibility in infrastructure changes, and long transmission distances. However, it requires active nodes to aggregate users’ fibers to reduce direct fiber connections to the central office.
– PON: Offers simpler maintenance with passive networks and potentially saves on optoelectronic devices and fibers. However, it requires expensive high-speed optoelectronic modules and careful management to avoid conflicts in upstream signals. PON’s transmission distance is limited by splitting ratios, and users’ downstream bandwidths are shared, requiring network expansion and module replacements to ensure bandwidth guarantees.
PON variants include APON, BPON, GPON, EPON, and WDM-PON, each tailored to specific network requirements. GPON and EPON have their respective advantages and are selected based on individual user needs.
In recent years, wireless access technologies have seen rapid development, such as IEEE 802.11g WLAN, which can fulfill users’ upstream requirements, complementing FTTH for downstream HDTV transmissions. This integration forms the basis for the future development trend of “FTTH + Wireless Access.”
- Development of Optical Switching
Optical fibers address transmission issues, but optical switching is essential to complete the communication process. While electronic switches were previously used in metallic cable-based networks, the transition to optical fibers necessitates optical switching. However, due to the immaturity of optical switch devices, current solutions rely on optical-electrical-optical (O-E-O) conversions, which are inefficient and uneconomical. Development of high-capacity optical switches, particularly Automatic Switched Optical Networks (ASON), is underway to realize efficient optical networks.
Most information transmitted in optical networks operates at xGbps speeds, surpassing the capabilities of electronic switches. Optical switching allows for high-speed XGbps exchanges, complementing electronic switches for low-speed, granular signal exchanges. While packet switching is prevalent in data networks, large-scale packet aggregation necessitates high-capacity optical switches. Current implementations support protection, grooming, and scheduling of low-volume channels, typically using mechanical or thermo-optic switches with limited channel counts.
Optical switching methods include space, time, and wavelength divisions, with space and wavelength divisions commonly used in fiber optic communications. Recent advancements include micro-electro-mechanical systems (MEMS) switches and wavelength routing experiments, demonstrating the flexibility of optical switching networks.
- Development of Integrated Optoelectronic Devices
Similar to electronic devices, optoelectronic devices are transitioning towards integration. While not all optoelectronic devices require integration, a significant portion can benefit from integration. Developments in planar lightwave circuits (PLC), which integrate optoelectronic devices onto a single substrate, facilitate the realization of FTTH and ASON networks by enabling compact, cost-effective solutions.
Japan’s NTT has developed integrated optoelectronic devices using PLC technology, including thermal optical switches, AWG multiplexers, and WDM modules, to construct scalable OADM solutions. China has also made progress in integrated optoelectronic devices, particularly in small-channel optical switches and PLC-based AWGs. However, there is still a considerable gap compared to developed countries, highlighting the need for technological catch-up to avoid passive roles in the optoelectronics industry.
In summary, the development of the fiber optic communication market is driven by advancements in FTTH, optical switching, and integrated optoelectronic devices. Efforts to improve bandwidth, reduce costs, and enhance network efficiency are crucial for meeting the growing demand for high-speed broadband services and supporting future communication needs.
