Novel TAMR Head Using Focusing Waveguide
Naoki Nishida＊, Hiroshi Hatano＊, Koujirou Sekine＊, Kenji Konno＊, Manami Saka＊ and Hiroaki Ueda＊

1

region of the waveguide4）. Then the light illuminates

Introduction

the plasmon head mounted on the bottom surface ofWe propose a practical optical system using athe waveguide. The plasmon head generates

focusing waveguide for thermally assisted magnetic

evanescent light of 20 nm in diameter which is usedrecording (TAMR). TAMR is known as an effectivefor a light source of TAMR.

recording method beyond the recording density of

The focusing waveguide consists of three parts as

1Tbit/inch overcoming the heat fluctuation problem.

1）

shown in Fig.2. Namely, the first core made of silicon,

The optics which focus the laser light on a plasmon

the second core made of SiOx, and the clad made ofhead for thermal assistance should be smaller than 1

SiO2. The first core has a tapered shape, whose cross-mm in height to be integrated into a flying slider

section is 400 nm × 220 nm at the bottom and 80 nm

between the platters of HDD. The beam spot diameter× 220 nm at the middle of the waveguide. The crossshould be less than 0.5μm considering the opticalsection of the second core was 3μm×3μm. The mode

efficiency of the plasmon head and total power

field diameter (MFD) of the light in the second core

consumption. Though various optics have been

was estimated to be 5μm. The second core wasreported so far

covered with the clad layer of over 5μm in thickness.

22 〜 3）, our proposal is most practical.

The incident light first coupled with the second core is2 ptical setup for TAMR with the focusingO
waveguide

coupled gradually with the first core and MFD of thelight becomes smaller while the light goes through thetapered region. The MFD is smaller than 0.5μm at

Schematic illustration of the proposed optics isthe bottom of the first core, because the light is

described in Fig.1. Light irradiated from the opticalconfined strongly due to the large refractive index

fiber is bent at the prism and goes into the focusing

difference.

waveguide which is integrated into a flying slider. The
diameter of the light spot is about 5μm at the top
surface of the waveguide. It is reduced to about 0.5μm while the light propagates 200μm in the focusing

Fig.2  Schematic layout of the focusing waveguide

3Fig.1  The TAMR optics

 valuation of optical spot focused by theEwaveguide
The focusing waveguide was fabricated by silicon on

insulator based process and assembled with an optical＊Frontier Business Incubation Department
Business Initiation Center
Konica Minolta Opto, Inc.

fiber precisely. Then a light of 1310 nm in wavelength
propagated through the fiber and entered into theKONICA MINOLTA TECHNOLOGY REPORT VOL.5（2008）

99

Focusing Waveguide. The MFD of the light at thebottom surface of the focusing waveguide was5Conclusion

measured using the scanning near-field optical

We have proposed novel optics using the Focusing

microscope (SNOM). The spot size was less than 0.5

Waveguide for TAMR. The focusing property of theμm, while the MFD at the top surface was about 5

waveguide and the plasmon enhancement have beenμm. Schematic layout of the measurement system andconfirmed successfully by the SNOM measurements.

the observed light spot are shown in Fig.3.

Therefore, it is expected that our focusing optics is oneof the most effective solutions of thermally assisted
magnetic recording.

Acknowledgement
The authors thank Prof. M. Ohtsu, Dr. T. Yatsui and
Dr. W. Nomura of the University of Tokyo for theirassistance to measure near field light using SNOM.
This paper belongs to ”Terabyte optical storage
technology” project which OITDA contracted withFig.3  The measurement system for the focusing properties andobserved spot.

4

 lasmon enhancements at wavelength ofP1310 nm
It is required to use the light of 1310 nm inwavelength for this optics, because the core of theFocusing Waveguide is made of silicon. We confirmedthat the plasmon enhancement occurs at the apex ofThe Ministry of Economy Trade and Industry of Japan(METI) in 2002 and contracted with The New Energyand Industrial Technology Development Organization(NEDO) since 2003 based on funds provided fromMETI.
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white arrows in the figure.

Fig.4  T he simulation result ofthe Plasmon enhancement

100Proceedings PA3.)

Fig.5  T he measurement system for the plasmon
enhancements and observed near field light

KONICA MINOLTA TECHNOLOGY REPORT VOL.5（2008）