ISSN 2086-5953
Figure 2. The uniformity of p-metal contact on the top of the
ridge and good isolation layer SiO
2
underneath.
3 EXPERIMENTAL RESULTS
There are several ways to analyze a tapered waveguide in order to see the amount of loss that
occurs. But, from several different techniques that have been used to analyze taper structures, a
general consensus has been made that if a taper is made long enough and has gradual enough taper
slope
, the taper can have low loss. It has been observed that taper lengths which are on the order
of hundreds of microns can achieve high output power and small threshold current, and also the
circular optical beam mode [7]. Table 1 and Table 2 show two samples characteristics of the total output
power and threshold current for the total laser cavity length vary from 400-700
m and 600-900 m, respectively. These results verify that for the
200 m taper length with 500 m cavity laser gives
the smaller threshold current and higher output power. And for the 500
m taper length with 800 m cavity laser also gives the smaller threshold
current and higher output power. Also, for the same cavity lengths 600 and 700
m with different taper lengths show the matching results with the
previous above analysis. Table 3 shows the best divergence angles of those FP lasers are 19
o
x 19
o
for lateral and vertical directions, respectively.
Table 1. Threshold current and output power characteristics for 200
m taper length.
Total cavity
length [ m]
Threshold current [mA]
Resistance [
] Output
power [mW]
400 40
22.8 2.4
500 22
16.8 8.6
600 26
23.3 2.7
700 32
20.8 6.6
Table 2. Threshold current and output power characteristics for
500 m taper length.
Total cavity length [
m] Threshold
current [mA] Resistance
[ ]
Output power
[mW] 600
54 29
1.4 700
36 19.3
4.1
800 33
25.2 5.2
900 33
25.7 3.8
Table 3. Divergence Angles Measurement Results No facet
coatings
Cavity Length µm
Taper Region µm
Divergence Angle deg FWHM=2α
200 100
22.25 22.06
500 200
19.48 19.19
700 200
21.89 22.19
800 500
19.37 19.23
Theoretical model for injection-locking FP- LD which shows the dynamic characteristics with
external injected narrow-band ASE light based on the rate equations for the semiconductor laser diode
refers to Ref [8]. This model was solved numerically by fourth-order Runge-Kutta method.
The simulation has been done and the calculated optical spectra of the wavelength-locked FP-LD has
was shown below Figure 3.
Figure 3. Simulated optical spectra of the wavelength-locked FP-LD [7].
By understanding the theoretical model that described above, we performed some experiments
for injection-locking technique. When we do not inject the external light into
the laser, the taper FP-LD shows multimode output. But, when an external narrowband optical signal is
injected into the multi-longitudinal mode laser such as vertical taper FP-LD, the lasing mode can be
locked to a single mode. The external optical signal from tunable laser diode acts as a seed for laser
oscillation in the FP cavity; moreover, the mode that is nearest to the peak wavelength of the
ISSN 2086-5953 injected optical signal will be locked to the injected
light, and other modes will be suppressed Figure 4. To increase the injection efficiency, we may
need the antireflection coating AR-coating on the front facet of the laser. Here, for injection-locking,
we used a FP-LD chip with 500 µm of total cavity length including 200 µ m taper and 300 µm laser
section with 5 of front facet reflectivity.
Figure 4. Measured optical spectra of the vertical taper FP-LD w and wo injection-locking.
4 CONCLUSION
The fabricated of vertical down-tapered ridge waveguide FP-LD was extremely smooth
using a simple and low-cost diffusion-limited etching method. The overall device length is 500
µ m, comprising the laser section 300 µm and taper length 200 µ m produced 8.6 mW output
power and 16 slope efficiency and 19
o
x 19
o
divergence angles for lateral and vertical which potentially can be used as a low-cost light source
for WDM-PON
based on
injection-locking technique. More than 30 dB SMSR was achieved at
100 mA bias current.
ACKNOWLEDGEMENT
This project was supported by National Science Council under grant of NSC97-2219-E-
011-004.
REFERENCES
[1] Banerjee A, Park Y, Clarke F and Song H,
Yang S, Kramer G, Kim K, and Mukherjee B 2005
Wavelength-division-multiplexed passive
optical network
WDM-PON technologies for broadband access: a review
[Invited]. Journal of Optical Networking 4: 737-757.
[2] Park S.-J, Lee C.-H, Jeong K.-T, Park H.-J,
Ahn J.-G, and Song K.-H 2004 Fiber-to-the- home services based on wavelength-division-
multiplexing passive optical network. Journal of Lightwave Technology 22: 2582-2591.
[3] Banerjee A, Park Y, Clarke F and Song H,
Yang S, Kramer G, Kim K, and Mukherjee B 2005
Wavelength-division-multiplexed passive
optical network
WDM-PON technologies for broadband access: a review
[Invited]. Journal of Optical Networking 4: 737-757.
[4] Park S.-J, Lee C.-H, Jeong K.-T, Park H.-J,
Ahn J.-G, and Song K.-H 2004 Fiber-to-the- home services based on wavelength-division-
multiplexing passive optical network. Journal of Lightwave Technology 22: 2582-2591.
[5] An F T, Kim K S, Hsueh Y L, Rogge M, Shaw
W T, and Kazovsky L G 2003 Evolution, challenges and enabling technologies for future
WDM-based optical
access networks.
Proceeding 2nd Symposium of Photonic Network Computing, Cary, NC, September,
2003. [6]
Kazovsky L.-G, Shaw W.-T, Guiterrez D, Cheng N, and Wong S.-W 2007 Next-
generation optical access networks. Journal of Lightwave Technology 25: 3428-3442.
[7] Jeon H, Verdiell J.-M, Ziari M, and Mathur A
1997 High
power low-divergence
semiconductor lasers for GaAs-based 980-nm and InP-based 1550-nm applications. Journal
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[8] Simatupang J. W, Wu W. S, and Lee S. L
2009 The Study of relative etching rate of masked InPInGaAsP in fabrication of vertical
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Surabaya, Indonesia, June 24-25, 2009, MI-26.
[9] Fan R. S, and Hooker R. B 1999 Tapered
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77 ISSN 2086-5953
MANAGEMENT DECISION MAKING FOR EXTENDED CROW METHOD TO PREDICT RELIABILITY OF SHIP OIL SYSTEM
Syamsuri
1
, Tungga Bhimadi
2 1
Department of Mechanical Engineering National Taiwan University of Science and Technology
2
Department of Naval Engineering Sepuluh Nopember Institute of Technology
Email: syam_sby2003yahoo.com
1
, tunggabhimadiyahoo.com
2
ABSTRACT
Method and
procedure selection
to recalculate the component and sub system
reliability growth after their failures have challenged researchers for satisfaction collaborating
and regulation of operating system. Reliability level was proposed compliance with: temporary using,
paralel circuit as stand by, impulsive system, real caused by routine maintenance, and Management
Decision Making MDM in repairing sub system or replacement component. This paper was
reliability growth approach using Reliability Growth of Extended Crow RGEC method.
Management decision that proposed are: scheduling in harmony, using non standard
component, handling after hazard, and using component or system resulted from innovation.
Time to Failure TTF data are needed to predict reliability growth of ship oil system until its
damage. The mean value of reliability was 64.3, and reliability level was 0.15 for 25 years operation
until the end of life time system.
Keywords: Reliability Growth of Extended Crow, Management Decision Making, Time to Failure.
1 INTRODUCTION
1.1 Motivation
