{"id":1089,"date":"2026-10-14T14:03:59","date_gmt":"2026-10-14T05:03:59","guid":{"rendered":"https:\/\/iupizeta.mgc.co.jp\/?post_type=column&#038;p=1089"},"modified":"2026-10-14T14:03:59","modified_gmt":"2026-10-14T05:03:59","slug":"optical-transceiver-resin","status":"publish","type":"column","link":"https:\/\/iupizeta.mgc.co.jp\/en\/column\/optical-transceiver-resin\/","title":{"rendered":"Can optical transceiver components be made from resin? The barrier posed by glass and ceramics"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">\ud83d\udccc <strong>Three-point summary<\/strong><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Optical components inside optical transceivers, such as FAU housings, optical engine housings, and microlens array holders, are still mainly made of quartz glass or ceramics.<\/li>\n\n\n\n<li>Glass and ceramics are inferior to resin in weight and productivity, but they have the advantage over resin in a low coefficient of thermal expansion (CTE) and in reflow heat resistance.<\/li>\n\n\n\n<li>An ultra-high-heat-resistance grade of Iupizeta EP that can overcome this barrier is under development, and it may be able to replace glass and ceramics in the future.<\/li>\n\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">What is an optical transceiver? Why glass and ceramics are used for its internal optical components<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">An optical transceiver (optical communication module) is a component that converts between electrical signals and optical signals. Installed in the switches and routers of data centers and communication base stations, it supports large-capacity communication.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Several optical components are built into it. Representative examples are the \u201cFAU housing\u201d (the housing of a fiber array unit), which arranges and fixes multiple optical fibers with high precision; the \u201coptical engine housing,\u201d which contains the optical engine that converts between electrical and optical signals; the \u201cmicrolens array holder,\u201d which fixes a microlens array in which many tiny lenses are arranged; and the \u201cferrule,\u201d a precision cylindrical part that holds the tip of an optical fiber.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Quartz glass and ceramics are still widely used for these components. One reason is their low CTE (an indicator of how much a material expands and contracts with temperature change). Because aligning optical fibers requires accuracy on the order of a few \u03bcm, materials whose dimensions hardly change with temperature have traditionally been chosen. For optical connector ferrules, zirconia (ZrO\u2082) ceramics, put into practical use in 1987 as a replacement for alumina, have since become the mainstream because of their high strength and toughness.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Two challenges of glass and ceramic components<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">Heavy weight<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Optical glass and ceramics are materials with a higher specific gravity than resin.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table>\n<colgroup>\n<col style=\"width: 61%\">\n<col style=\"width: 38%\">\n<\/colgroup>\n<thead>\n<tr>\n<th>Material<\/th>\n<th>Specific gravity (g\/cm\u00b3)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Quartz glass (synthetic quartz)<\/td>\n<td>2.20<\/td>\n<\/tr>\n<tr>\n<td>Alumina<\/td>\n<td>3.9<\/td>\n<\/tr>\n<tr>\n<td>Zirconia<\/td>\n<td>6.0<\/td>\n<\/tr>\n<tr>\n<td>Optical resin (reference range)<\/td>\n<td>1.0\u20131.2<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">Ceramics are even heavier than quartz glass, and the specific gravity difference from resin is larger than it is for glass. In an optical transceiver, which incorporates many components, this specific gravity difference directly affects the weight of the whole module.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Difficulty of raising productivity<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">The temperatures required for molding and processing also differ greatly. Glass molding requires heating to around 600\u2013700\u00b0C, and ceramic sintering is generally a high-temperature process well above 1,000\u00b0C. Resin injection molding, in contrast, is carried out at a much lower temperature of around 200\u2013300\u00b0C, which causes less mold wear and suits continuous production.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">High-temperature processes shorten mold life and tend to require large-scale processing equipment. Resin, which can be molded at low temperature, has characteristics suited to mass production in this respect.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">The potential for solving these challenges by switching to resin<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Replacing glass and ceramics with resin may solve these challenges.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Weight reduction<\/strong>: A simple estimate based only on the difference in specific gravity suggests that switching to resin could theoretically reduce weight to about one-half to one-fifth (actual component weight varies with shape and wall thickness, so this is only a guide based on the specific gravity difference of the materials)<\/li>\n\n\n\n<li><strong>Higher productivity<\/strong>: Resin injection molding is performed at a much lower temperature than glass molding or ceramic sintering, so mold wear is low and the process suits continuous production<\/li>\n\n\n\n<li><strong>Greater design freedom<\/strong>: Using a resin with a high refractive index makes it possible to achieve the same optical performance with a gentler curvature and a thinner shape. This is a benefit common to optical resins, which was also explained in our article on converting microlens arrays to resin.<\/li>\n\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Barriers to switching to resin: CTE and reflow heat resistance<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">On the other hand, there are also challenges in switching to resin that must be faced honestly.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">CTE<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table>\n<colgroup>\n<col style=\"width: 56%\">\n<col style=\"width: 43%\">\n<\/colgroup>\n<thead>\n<tr>\n<th>Material<\/th>\n<th>CTE (ppm\/K)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Quartz glass (synthetic quartz)<\/td>\n<td>0.5\u20130.6<\/td>\n<\/tr>\n<tr>\n<td>Alumina<\/td>\n<td>8<\/td>\n<\/tr>\n<tr>\n<td>Zirconia<\/td>\n<td>11<\/td>\n<\/tr>\n<tr>\n<td>Polycarbonate (reference value)<\/td>\n<td>approx. 66<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">The CTE of quartz glass is extremely small, ceramics are an order of magnitude higher, and resin is another order of magnitude higher still. For components that require fiber positioning accuracy, the magnitude of CTE is a factor that puts resin at a relative disadvantage in terms of dimensional stability.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Reflow heat resistance<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Because optical transceivers are surface-mounted on printed circuit boards, they go through a soldering process called \u201creflow\u201d during manufacturing. The lead-free solder reflow process is generally said to reach high temperatures in the upper 200\u00b0C range (IPC\/JEDEC J-STD-020 is known as a standard that classifies the moisture sensitivity and reflow resistance of surface-mount components).<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The glass transition temperature (Tg, a guide to the temperature at which a resin begins to change from a hard state to a soft state) of the standard grades of Iupizeta EP (EP-4500 to EP-9000) is 140\u2013145\u00b0C. This is far below the temperature of the reflow process, so the standard grades are considered to risk softening and deformation during board mounting. This is a constraint that must be honestly acknowledged when considering conversion to resin.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Iupizeta EP as an option<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Iupizeta EP is an optical resin that has achieved both a high refractive index and low birefringence through molecular design. On the other hand, in optical transceiver mounting, parts must pass through \u201creflow,\u201d the soldering process onto the board, and lead-free reflow reaches high temperatures in the upper 200\u00b0C range. For this reason, the standard grades (EP-4500 to EP-9000, Tg = 140\u2013145\u00b0C) risk softening or deformation in the reflow process depending on the application, shape, and conditions, and this can be a constraint for components that must withstand reflow.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Mitsubishi Gas Chemical (MGC) is therefore investigating an ultra-high-heat-resistance development material that maintains the optical characteristics that are its traditional strength while also anticipating the reflow process. For example, MGC is developing resins with the following properties.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Development material A: refractive index nd = 1.61, Tg = 264\u00b0C<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Development material B: refractive index nd = 1.63, Tg = 280\u00b0C<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Both show good internal transmittance in the 1310 nm and 1550 nm bands widely used in optical communication, which contributes to the lower loss required of optical components. In addition, their birefringence is far lower than that of thermoplastic polyimide and polyetherimide (PEI), and the dimensional change caused by water absorption is markedly smaller than that of thermoplastic polyimide and PEI, so they have characteristics that make them easy to consider even for applications in which stable optical alignment under fluctuating temperature and humidity is a challenge.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The CTE is lower than that of ordinary polycarbonate resin, but it is still large compared with quartz glass and ceramics. MGC is therefore also investigating ways to lower the CTE further, with a view to applying the materials to components where positioning accuracy and temperature stability are especially important, such as FAU housings and optical engine housings.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Furthermore, since a certain degree of transmittance is expected for light near 365 nm, MGC is also examining applicability to fixing processes that use UV curing (UV-curable adhesives, etc.). If fixing by UV in a short time after optical alignment becomes possible, benefits are expected in process design freedom and mass producibility (actual applicability requires evaluation that takes into account the adhesive, film thickness, shape, irradiation conditions, and so on).<\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img decoding=\"async\" width=\"2300\" height=\"1957\" src=\"https:\/\/iupizeta.mgc.co.jp\/cms\/wp-content\/uploads\/2026\/10\/image1-1.png\" alt=\"\" class=\"wp-image-1090\" srcset=\"https:\/\/iupizeta.mgc.co.jp\/cms\/wp-content\/uploads\/2026\/10\/image1-1.png 2300w, https:\/\/iupizeta.mgc.co.jp\/cms\/wp-content\/uploads\/2026\/10\/image1-1-300x255.png 300w, https:\/\/iupizeta.mgc.co.jp\/cms\/wp-content\/uploads\/2026\/10\/image1-1-1024x871.png 1024w, https:\/\/iupizeta.mgc.co.jp\/cms\/wp-content\/uploads\/2026\/10\/image1-1-768x653.png 768w, https:\/\/iupizeta.mgc.co.jp\/cms\/wp-content\/uploads\/2026\/10\/image1-1-1536x1307.png 1536w, https:\/\/iupizeta.mgc.co.jp\/cms\/wp-content\/uploads\/2026\/10\/image1-1-2048x1743.png 2048w\" sizes=\"(max-width: 2300px) 100vw, 2300px\" \/><\/figure>\n\n\n\n<p class=\"wp-block-paragraph\">For FAU housings, optical engine housings, microlens array holders, and other components that quartz glass and ceramics have traditionally served, MGC can propose materials that meet required specifications, including reflow heat resistance, while taking advantage of the benefits of resin: weight reduction and improved mass producibility. For details on applicability and conditions, please feel free to reach out.<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">Summary: considering a switch from glass and ceramics to resin<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Quartz glass and ceramics are currently the mainstream materials for FAU housings and optical engine housings inside optical transceivers, but switching to resin may solve the problems of weight and productivity. Barriers remain in CTE and reflow heat resistance, but there are signs that, as the development of ultra-high-heat-resistance materials progresses, these barriers may be overcome.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">For optical component material selection, grade-by-grade property information and development status can be checked on the Iupizeta EP official website (<a href=\"https:\/\/iupizeta.mgc.co.jp\/en\/\">https:\/\/iupizeta.mgc.co.jp\/en\/<\/a>).<\/p>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<p class=\"has-small-font-size wp-block-paragraph\">Some images and text in this article were created with the help of generative AI.<\/p>\n\n","protected":false},"featured_media":1087,"template":"","meta":{"_acf_changed":false,"_locale":"en_US","_original_post":"https:\/\/iupizeta.mgc.co.jp\/?post_type=column&p=1088"},"column_tax":[52],"class_list":["post-1089","column","type-column","status-publish","has-post-thumbnail","hentry","column_tax-basics","en-US"],"acf":[],"_links":{"self":[{"href":"https:\/\/iupizeta.mgc.co.jp\/wp-json\/wp\/v2\/column\/1089","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/iupizeta.mgc.co.jp\/wp-json\/wp\/v2\/column"}],"about":[{"href":"https:\/\/iupizeta.mgc.co.jp\/wp-json\/wp\/v2\/types\/column"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/iupizeta.mgc.co.jp\/wp-json\/wp\/v2\/media\/1087"}],"wp:attachment":[{"href":"https:\/\/iupizeta.mgc.co.jp\/wp-json\/wp\/v2\/media?parent=1089"}],"wp:term":[{"taxonomy":"column_tax","embeddable":true,"href":"https:\/\/iupizeta.mgc.co.jp\/wp-json\/wp\/v2\/column_tax?post=1089"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}