A marriage of optical fibre fabrication technology and LSI microfabrication technology gave birth to fibre-matched silica waveguides on silicon: thick glass layers of high-silica-content glass are deposited on silicon by flame hydrolysis, a method originally developed for fibre preform fabrication. Silica channel waveguides are then formed by photolithographic pattern definition processes followed by reactive ion etching. This ‘high silica (HiS) technology’ offers the possibility of integrating a number of passive functions on a single silicon chip, as well as the possibility of the hybrid integration of both active and passive devices on silicon. This paper reviews the NTT HiS technology and its application to integrated-optic components such as optical beam splitters, optical switches, wavelength-division multi/demultiplexers and optical frequency-division multi/demultiplexers. The clear and simple waveguide structures produced by the HiS technology make it possible to design and fabricate these components with high precision and excellent reproducibility.

Silica waveguides on silicon and their application to integrated-optic components

TUTORIAL REVIEW Silica waveguides on silicon and their application to integrated-optic components

Thermally expanded core (TEC) fiber is expected to reduce fiber-to-fiber and fiber-to-laser diode connection loss This paper describes the characteristics of TEC fiber theoretically and experimentally We reveal theoretically that when fabricating TEC fiber the mode field diameter (MFD) is enlarged more effectively by increasing the heating temperature rather than the heating time In the 1300-1600/spl deg/C temperature range with heating times between 0 and 60 min, it is necessary to control the temperature accurately so that no deviation from the target temperature is more than /spl plusmn/30/spl deg/C This is in order to ensure that any connection loss caused by MFD mismatch is less than 01 dB We show experimentally that the propagation loss of TEC fiber is dependent on the heating region and wavelength by using a micro burner with a propane/oxygen flame Based on the relationship between the loss characteristics and the expanded MFD, we suggest a method for nondestructively measuring the MFD in TEC fibers

Characteristics of thermally expanded core fiber

To provide an optical module capable of miniaturization, the optical module, to which an optical plug provided at one end of an optical transmission path is attached, so as to transmit and receive signal light via the optical transmission path for information communication, includes: a transparent substrate having light transmittance property with respect to a wavelength of used signal light; an optical socket, which is arranged on one surface side of the transparent substrate and to which the optical plug is attached; an optical element, which is arranged on the other surface side of the transparent substrate and emits the signal light to the one surface side of the transparent substrate according to a supplied electrical signal, or generates an electrical signal according to the intensity of the signal light supplied from the other surface of the transparent substrate; and a reflective portion, which is arranged on the other surface of the transparent substrate and changes a path of the signal light emitted from the optical element at substantially 90 degrees to guide it to the optical transmission path, or changes a path of the signal light emitted from the optical transmission path at substantially 90 degrees to guide it to the optical element.

Optical module and manufacturing method of the same, optical communication device, opto-electrical hybrid integrated circuit, circuit board, and electronic apparatus

An optical module may include precise guide pins formed in a transparent substrate or an optical transmission line support member. The precise guide pins may be inserted into corresponding precise guide holes within the transparent substrate or the optical transmission line support member to precisely align optical elements. The precise guide holes may be formed within one of the transparent substrate and the optical transmission line support member by positioning protruding portions of a jig within over-sized guide holes and filling a gap between the protruding portions of the jig and the respective over-sized guide holes with a filler material. Once the filler material is cured, the jig may be withdrawn leaving precisely positioned guide holes.

Optical module and method of manufacturing the same, and hybrid integrated circuit, hybrid circuit board, electronic apparatus, opto-electricity mixed device, and method of manufacturing the same

A demountable optical connector for a single-mode fiber-ribbon has been developed that uses a multi-V-groove molding method. The connector is easily installed for both a single-mode fiber-ribbon and individual monocoated fibers. The connecting loss due to errors in ferrule fabrication has been analyzed in detail. The fabricated five-fiber connector exhibited an average connecting loss of 0.5 dB and loss changes of approximately ±0.1 dB for repeated reconnections.

A new type of demountable plastic-molded single-mode multifiber connector

A small plastic molded single-mode ten-fiber connector has been developed for high-count optical subscriber cables. The connector ferrule alignment mechanism is designed with a sufficient factor of safety to allow rough handling during connection. The ferrules are precisely aligned by alignment pins and guide sleeve. The fabricated connector, which has a cross section of just 4 mm * 6 mm, exhibited an average loss of 0.4 dB and reconnection time of less than 0.5 min. Connection loss does not change after over 1000 reconnections. >

Very small single-mode ten-fiber connector

This paper describes the design and performance of next generation, single-mode, multi-fiber, debris insensitive, expanded beam, interconnect components. This low cost, dense optical interconnect technology combined with recent advances next generation, high bandwidth, SM, silicon photonic based Tx/Rx devices is enabling unprecedented bandwidth densities for extended distances at reduced costs. A monolithic, multi-fiber ferule with integrated collimating lenses was designed with the same overall footprint as a traditional MT-type, multi-fiber rectangular ferrule. The new optical ferrule was designed with precision micro holes for alignment to the lens array allowing for future incorporation of multiple rows of fibers into a single ferrule unit. The monolithic, lensed based ferule design enables a low-cost, no-polish fiber termination methodology. The ferrule tested was manufactured with an array of 16 fibers in the footprint associated with traditional, 12 fiber, physical contact MT ferules via use of novel, molded in, end-face alignment features. Multiple optical models were built with ray tracing methodology to predict the insertion loss and return loss with varying refraction index, transmissivity and surface reflection properties of the ferrule. Empirical optical performance results closely match the optical modeling predictions. Insertion losses of <1.5dB were measured along with return loss values <=-30dB. Further analysis was done to characterize the robustness of the new interconnect with regard to debris insensitivity. Do to the nature of the expanded beam, free-space optical design, the impact of debris on the optical mating surface of the interconnect was significantly reduced when compared to traditional, physical contact single-mode interconnects

New single-mode, multi-fiber, expanded-beam, passive optical interconnect

MPO-type single-mode multi-fiber connector: Low-loss and high-return-loss intermateability of APC-MPO connectors

PURPOSE:To realize a precise switch by easy assembling and to form a multicore batch switch by providing circular positioning guide pins between plugs in two states before and after the switching of an optical fiber switch, and circular holes and rectangular holes which are formed in the plug themselves. CONSTITUTION:An input-side optical fiber 1 is arranged in the input-side plug 9 of the optical switch and optical fibers 1' and 2' are arranged in the output- side plug 10 at a center interval. The circular holes 11 with an external diameter D are formed in the plug 9 on both sides of the fiber 1, and the circular guide pins 12 are inscribed with the circular holes 11 so that their one-end sides project by specific length. Further, the rectangular holes 13 which have long sides of length D+P and short sides of length D are formed on both sides of the fibers 1' and 2'. The projection parts of the pins 12 of the input-side plug 9 are inserted into the holes 13 of the output side and the plugs 9 and 10 are set in an abutting state to fix the plug 9; and the plug 10 is pressed upward or downward to realize the accurate switch by the easy assembly.

Toshiaki Satake

Papers

A new type of demountable plastic-molded single-mode multifiber connector

Very small single-mode ten-fiber connector

New single-mode, multi-fiber, expanded-beam, passive optical interconnect

MPO-type single-mode multi-fiber connector: Low-loss and high-return-loss intermateability of APC-MPO connectors

Optical fiber switch