Analysis of PLC Splitter Market Technology

The optical splitter is the core of the FTTH optical device. It has great growth potential and will become the main driver for the growth of the FTTX market. It will undoubtedly bring vitality and challenges to the optical communications manufacturing industry, and it will also give optical communications companies Bring another space for rapid development. This article reviews the PLC splitter market, industry conditions and technological development status. The development of PLC chips, fiber arrays, and coupling packaging technology was analyzed.

1 Introduction

At present, China’s FTTx (Fiber Optic Access Network) construction is gradually underway. The three major operators and radio and television systems have all determined the concept of “speeding up the transition from copper to copper and advancing the strategic transformation of access networks” to achieve FTTC (Fiber to the Curb). FTTB (fibre to the building), FTTH (fibre to the home), FTTD (fibre to the desktop), triple-play (voice, data, cable) and other multimedia transmissions and PDS (Comprehensive Cabling System) solutions. To build an all-fiber network, in addition to the need for various types of structured distribution fiber optic cables, the introduction of fiber optic cables to achieve the continuation and redistribution of fiber optic networks, in the E-PON and G-PON technologies, a large number of optical splitters are required to complete the final Fiber-to-the-home purpose.

The FTTx system consists of three parts: the central office equipment (OLT), the user terminal equipment (ONU), and the optical distribution network (ODN). As an important part of an FTTx system, an ODN is a physical path for optical transmission between an OLT and an ONU. It is usually composed of an optical fiber cable, an optical connector, an optical splitter, and supporting equipment for connecting and connecting these devices. From the ODF rack in the central office to the feeder section of the cable distribution point, it is used as a backbone optical cable to achieve long-distance coverage. From the optical cable distribution point to the wiring section of the user access point, the optical fiber is distributed to the user area along the feeder optical cable. The user access point to the terminal's home segment is completed by a butterfly-shaped fiber optic cable, and all branch and contact connections are accomplished by optical splitters and enable fiber access.

The optical splitter is the core of the FTTH optical device. It has great growth potential and will become the main driver for the growth of the FTTX market. It will undoubtedly bring vitality and challenges to the optical communications manufacturing industry, and it will also give optical communications companies Bring another space for rapid development. According to the advent of the access network construction boom, from the current stage of the market and the future development trend of demand, PLC optical splitter will become the main force of the PON market has been beyond reproach, he has digital, network, broadband, miniaturization and easy maintenance Features are the focus of future market demand.

2. PLC (optical splitter) market and industry conditions

2.1 PLC (optical splitter) market conditions

PLC (optical splitter) is mainly used in the access network passive optical network (PON), so that the central office and multiple users connected to achieve fiber to the home. In 2008, the global demand was about 24 million channels, with total sales of 110 million US dollars and an average of 4.6 US dollars. The global market is different in different regions. After Japan and South Korea have been developing at high speed for several consecutive years, the demand quantity has stabilized, but it still occupies half of the market share. North America has a market share of 30%. The development of FTTH in developing countries such as China, India, and Brazil will be the main growth point of the market.

In 2009, the demand for China's optical device market was strong, especially since the second quarter. Sales revenue continued to grow for three consecutive quarters. In terms of products, the performance of 10G optical modules and PLC products is remarkable, and the growth is strong. In the first and second quarters of 2010, the order of domestic passive device manufacturers was in good condition. The market demand was about 600 million yuan, an increase of 16% year-on-year. With the acceleration of FTTX deployment by operators, the domestic PLC device market continued strong growth in 2009, and PLC splitters, AWGs and other products were in great demand. At present, the market demand for passive components such as fiber optic connectors, couplers, isolators, and attenuators continues to grow steadily. However, due to further intensified market competition, prices have continued to decline.

In terms of operators, the three major operators have explicitly requested that all FTTX networks use PLC-type optical splitters. From 2009 to 2010, China Telecom and China Unicom have conducted bidding for PLC splitters for two consecutive years. In 2010, China Mobile has also started to collect all the equipment used by GPON, including PLC splitters. Mining.

If the optical device market growth in 2009 is a 3G factor, then the growth factor in 2010 will be the FTTX factor. Although there are still many obstacles to the large-scale deployment of FTTX networks in China, the government's decision to promote triple play will give FTTX a strong boost and the optical device market will benefit. In the first half of 2010, under the active promotion of FTTH construction and 3G network construction by operators, and on January 13, 2010, Premier Wen Jiabao of the State Council presided over the State Council Executive Meeting and decided to accelerate the integration of the telecommunications network, radio and television networks, and the Internet. This shows that the government will begin to promote the deployment of FTTX networks and the optical device market will benefit. According to ICCSZ's forecast, the domestic optical device market will maintain a steady growth in 2010, and domestic passive device market sales will maintain rapid growth. In the second quarter, domestic passive device sales will be about 700 million yuan, an increase of 17.8% year-on-year. In the second quarter, the state issued the "Opinions on Promoting the Construction of Fiber-optic Broadband Networks" to accelerate the construction of fiber-optic broadband networks. At present, the Tri-network convergence pilot program has also passed. These factors have effectively promoted further growth in the market demand for optical devices, and also brought a large number of orders for passive device manufacturers. At present, the domestic FTTx network deployment process is accelerating, PLC products as the core device of FTTX, will also obtain a large number of applications, China's optical device market demand will reach 3.6 billion yuan, an increase of 7.5%. It is expected that in the second half of 2010, the Chinese optical device market will continue to maintain growth.

2.2 PLC (optical splitter) industry

At present, China is already a manufacturing country of PLC devices. Most of the global products are produced in China and South Korea. There are about 100 optical splitter manufacturers in China (including foreign-funded enterprises), about 20 manufacturers and R&D capabilities. (From China Telecom's PLC collection and procurement information in 2010, nearly 100 enterprises across the country participate in collective bidding ), Among which, Fiberhome, Wuhan Vision Technologies, Cretron Technology, Fuchuang Optoelectronics, Aokang Optical Components, Wuxi Aiwofu, Fuchunjiang Optoelectronics, Shenzhen Rihai Communications, Chengdu Feiyang Technology, Shanghai Shangcheng, Datang Communications (Kunshan), Nanjing Putian, Zhejiang Pushen and other companies have become mass-produced. In addition to chip outsourcing, others are produced by themselves. In addition, most companies do not have a large climate in terms of product variety or production scale, and some companies basically buy the main body of splitters, and then add jumper heads and shell assembly models.

At present, all countries are vigorously promoting the FTTH and FTTx projects. With the development of FTTx (fiber access network) in China, the demand for PLC splitters in the market is apparently large. The PLC optical splitter may be the next passive component. The focus of market demand. In addition to increasing the development and production capacity of professional optical device manufacturers, some well-known optical fiber and cable manufacturers have also increased investment in this area, actively developing passive device products, while also adding production equipment, and taking this as The technology and product reserves, with its ready and planned market share, show the importance of PLC optical splitters in the market in the coming years and the importance that major optical device companies and optical fiber and cable companies attach to this project. However, China has not yet mastered the chip technology and can only purchase chips externally for packaging or OEM.

2.3 PLC (optical splitter) market price trend

In the future, China will occupy the leading position in the PLC splitter market, and it is expected to occupy 35% of the market in three years. The core technology chip of PLC-Splitter is still in the hands of companies in Europe, America, Japan and South Korea. Because there is no core technology, domestic companies can only develop Fiber Arrays to purchase chips for packaging or to directly do OEM work for chip companies.

Everything has two sides, the increase in demand is always accompanied by a drop in product prices, due to a large number of domestic device packaging companies influx into this market, coupled with the three major operations on the PLC optical splitter collection, the market price It will face a downward trend. With the continuous increase in demand, prices will become lower and lower. The profits of OEM companies and packaging companies will also become thinner and thinner. Figure 1 shows the international PLC price trend.

2.4 PLC (optical splitter) industry development problems

There are also certain problems in the development of the PLC optical splitter industry in China. Although the market demand is large, the expansion of production capacity and the potential risk of oversupply in the market are also rapidly increasing. First, due to increasing pressure on manufacturing costs, especially for companies with coupling and packaging follow-up processes, the current price of PLC optical splitters has dropped by about 40% compared to that at the beginning of 2008, and PLC splitters are currently available. Relatively mature, with large-scale production, prices and gross margins will continue to fall, the trend of market consolidation becomes more obvious. With the homogenization competition of the second domestic manufacturers, chips, V-slots, and even FAs all depend on imports. The cost pressure is very high. If the company is small, the cost pressures it will face will be even greater, because the source of the material is mainly outsourcing, and the cost is inversely proportional to the purchase volume. If the outsourcing volume is small, the outsourcing price will also be relatively high. It can be a difference of 20% to 30%. The third is the impact of WDM-PON on PLC splitters. In addition to the EPON and GPON that we often mention, there are WDM-PONs. The evolution of next-generation fiber access technology is likely to be WDM-PON technology, and European and American countries are more interested in this technology. However, from a technical standpoint, the existing EPON multiplexing method is a power split type, while the WDM-PON belongs to wavelength division multiplexing, that is, the existing PLC splitter does not apply to WDM-PON technology If the process of this technology evolution is short, PLC splitter manufacturers will face severe tests and equipment and capital input costs will be difficult to recover.

3. PLC (optical splitter) technology development

Low cost and high reliability are basic requirements for optical splitter devices in FTTH engineering. Optical splitters for optical communication can be classified into two types: optical fiber fusion taper type and planar integrated optical waveguide type.

Optical fiber fusion taper technology is the most mature technology for producing 2 ́2 optical splitters. Optical splitters are mainly based on all-fiber optical splitters. Their main features are: mature technology and easy connection with optical fibers. , The insertion loss is small. However, as the number of power splitters increases, optical splitters with a size of 1×8 or more are bulky, inefficient, and costly, and have poor spectral uniformity. In addition, the characteristics of the optical fiber splitters such as the passbands based on the fusion taper technology have great limitations.

PLC based on planar technology integrated optics. Different from the traditional discrete device, he uses the semiconductor process to manufacture. It can integrate optical components with different functions into a single chip. It is a basic process technology to realize the integration, scale, and miniaturization of optoelectronic devices. Compared with the fused-tapered technology, the planar waveguide technology has the outstanding features of stable performance, low cost, and suitable for large-scale production. Therefore, optical fiber fusion taper optical power splitting devices will no longer be used in fiber-to-the-home systems in the future, and planar waveguides provide an effective way for the production of high-performance, low-cost optical devices for access networks.

3.1 PLC chip technology

PLC chips are generally fabricated on six materials. They are: lithium niobate (LiNbO3). The waveguide is formed by diffusing Ti ions on a lithium niobate crystal to form a waveguide. The waveguide structure is diffusion type; III-V semiconductor compound, waveguide Use InP as bottom and bottom cladding, InGaAsP as core, InP or InP/air as upper cladding, waveguide structure as buried ridge or ridge, SOI (Silicon-on-Insulator, silicon on insulator), The waveguide is fabricated on a SOI substrate. The bottom, bottom cladding, core and upper clad materials are Si, SiO2, Si and air, respectively, and the waveguide structure is ridge-shaped and polymer and silicon dioxide (SiO2). , Glass ion exchange, etc.

At present, fiber-to-the-home (FTTH) network technology has no problem, but whether it can rapidly develop and popularize in China, in addition to policy, the most important and most critical point is to reduce the cost of the various aspects of the network. The PLC optical splitter is one of the core devices in the FTTx network. Low cost is an important technical development goal. From the technology, cost, and characteristics of the optical waveguide materials given in the above table, it can be seen that silicon dioxide, polymer, and glass are the most suitable for making PLC chips. The following is a brief introduction of three PLC chip technologies that have the lowest cost and are most easily realized in industrialization:

(1) Polymer (Spin-Coating - Etching)

The polymer waveguide uses a silicon wafer as a base, a polymer material with different doping concentrations as a core, and a waveguide structure as a buried rectangle. The manufacturing process of polymer waveguides and devices is simple, inexpensive, and if it is more photoreceptive and the production cost is lower (theoretical value), there is great potential for development. The problem is that the cost of fluorinated materials is high; aging doubts and losses will be relatively high; and the stability of the product needs to consider its impact. At present, only Shanghai NITTA company has this chip as optical splitter products.

(2) Silicon dioxide

Silica waveguides are known as silicon wafers, with differently doped SiO2 materials as the core and cladding, and the waveguide structure as a buried rectangle. Silica-based silica lightwave technology is a new technology developed in the 1990s and has matured abroad. Its manufacturing processes include flame hydrolysis (FHD), chemical vapor deposition (PECVD, developed by NEC Japan), plasma CVD (developed by Lucent, USA), porous silicon oxidation, and Sol-gel. Wait. This kind of waveguide and loss is very small, about 0.05dB/cm or less. Abroad has used this kind of waveguide to develop 60-way, 132-way AWG. At present, the use of flame hydrolysis method (FHD) and chemical vapor deposition (PECVD) for the growth of multi-layered silicon dioxide materials is used, and the waveguide etching is performed using a dry etching technique. Its advantage is that it has very good physical and chemical stability technology, high device integration, and low cost. At the same time, it has good compatibility with optical fiber, low transmission loss, mature technology (mainly depends on the import of equipment), and the product is stable and reliable. Theoretically, other AWG and other PLC devices can also be produced. This process technology is currently the mainstream technology for the manufacture of chip products, and is more commonly used internationally. There are high equipment investment costs, high maintenance costs, and high raw material requirements (all imported materials are used); there are only a few scientific research institutes and university laboratory equipment online and Wuhan Science and Technology silicon dioxide PLC process line, not yet available Industrial scale production equipment. This technology and manufacturing are basically monopolized by foreign companies such as South Korea and Japan.