KYOCERA Develops Temperature Characteristics-Free Etalon Filter

  KYOCERA Develops Temperature Characteristics-Free Etalon Filter

 Crystal device applies atomic diffusion bonding technique for first time in
 the industry, contributing to downsizing and energy conservation in tunable
                 laser modules for optical communication WDM

Business Wire

KYOTO, Japan -- December 12, 2012

Kyocera Corporation (NYSE:KYO)(TOKYO:6971) today announced that its wholly
owned subsidiary Kyocera Crystal Device Corporation, in charge of development
and manufacturing of crystal devices, has succeeded in developing a
temperature characteristics-free etalon filter — a crystal device which has
applied the atomic diffusion bonding technique for the first time in the

An etalon filter is a component which detects deviations in multiple light
wavelengths in high-capacity optical communication transmissions systems. For
this new product, Kyocera Crystal Device has realized a temperature
characteristics-free etalon filter with high-accuracy, high-reliability and
smaller size due to its success in developing a crystal device applying the
atomic diffusion bonding technique. The product will be available on a sample
basis starting January 2013.

Product name:           Temperature characteristics-free etalon filter (C
Applications:            Tunable laser module for optical communications and
                         industrial use
                         - External dimensions: >1.2mm squared

                         - Adaptive wavelength: 1,520 to 1,620nm

Main specs:              - Temperature characteristics: ±0.15pm /°C typ.
                         (pm/°C = 10^-12m/°C)

                         - FSR: 50/100GHz

                         - Extinction ratio or reflectance: Custom
Availability:            Starting in January 2013
Production facilities:  KYOCERA Crystal Device Hokkaido Corporation (Japan)

Main Features

1. Industry-leading product specifications enable freedom from temperature

The new product has achieved an industry-leading level of temperature
characteristics of ±0.15pm/°C. This was achieved by applying a design
technique combining positive temperature characteristic crystals with negative
temperature characteristic crystals and an advanced crystal processing
technique, along with industry's first application of the atomic diffusion
bonding technique. Furthermore, since the temperature characteristics-free
etalon filter does not require a Peltier device for temperature adjustment, it
can contribute to downsizing and energy conservation in tunable laser modules.

2. Industry's first crystal device to apply atomic diffusion bonding technique

The atomic diffusion bonding technique is a direct bonding technique developed
by Tohoku University's Professor Takehito Shimatsu. It entails bonding the
wafer and substrate together without applying heat, pressure or voltage, nor
using organic adhesives. Through the joint-development with Professor
Shimatsu's research group, Kyocera Crystal Device has succeeded in bonding a
crystal wafer in an extremely thin metal film thickness of several atomic
layers to several dozen nanometers^*2 with high strength by applying the
atomic diffusion bonding technique for crystal devices. This method has solved
the problems of optical contact^*3, a conventional bonding method with lower
bonding strength, and that of bonding using organic adhesive, for which the
management of bonding thickness is difficult. It has also improved accuracy
and reliability while reducing the size of the etalon filter.

Development Background

An etalon filter is a component which monitors whether oscillation of light
wavelength is steadily conducted in the tunable laser module — an essential
device used for high-capacity optical communication transmission systems —
which transforms electric signals to optical signals for oscillation.

In recent years, optical communication has become increasingly essential to
achieve higher capacity and higher transmission speeds with the dramatic
increase in information volume due to the rapid spread of the Internet and
transmission of high-volume data. To respond to such requirements, the
utilization of the WDM^*4 transmission system, which can transmit more optical
signals (information volume) with one piece of optical fiber, has become the
mainstream method. Since a WDM transmission system requires many tunable laser
modules for each station from mid- to long-distance to short-distance
transmissions, further reduction in size and electric power consumption is

As the product does not require a Peltier device for temperature control due
to the aforementioned features, it can contribute to reduction in the size and
electric power consumption of tunable laser modules. Even with its small size,
this product has realized freedom from temperature characteristics, high
accuracy and high reliability, and has superior stability against changes in
external temperature.

Kyocera Crystal Device has an integrated production system, in which all the
processes from cultivation of crystal materials to design, processing, coating
and characteristics evaluation are all conducted internally. The company will
continue to enhance its support of optical transmission-related fields in
order to contribute to the further progress and development of high-capacity,
high-speed optical communications networks.

^*1 As of November 15, 2012. Based on a survey by Kyocera Crystal Device.
^*2 1 nanometer (nm) = 1.0x10^-9m.
^*3 Bonding method that does not use adhesive but bonds flat surfaces of the
wafer together.
^*4 WDM: Wavelength Division Multiplexing. A communication technology that
utilizes optical fiber.

For see more info and images of this product:


Kyocera Corporation (NYSE:KYO)(TOKYO:6971) (, the
parent and global headquarters of the Kyocera Group, was founded in 1959 as a
producer of fine ceramics (also known as "advanced ceramics"). By combining
these engineered materials with metals and plastics, and integrating them with
other technologies, Kyocera has become a leading supplier of electronic
components, semiconductor packages, telecommunications equipment, solar power
generating systems, printers, copiers, cutting tools and industrial ceramics.
During the year ended March 31, 2012, the company's net sales totaled 1.19
trillion yen (approx. USD14.5 billion). The company is ranked #426 on Forbes
magazine's 2012 "Global 2000" listing of the world's largest publicly traded


KYOCERA Corporation (Japan)
Judah Reynolds, +81-(0)75-604-3416
Corporate Communications
Fax: +81-(0)75-604-3516
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