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Multi-wavelength Semiconductor Fiber Lasers

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Reuven E. Gordon, V ronique Pag , Dr. Varghese Baby. Serge Doucet, Prof. Sophie LaRochelle ... NSERC Canada and Canadian Institute for Photonic Innovations ... – PowerPoint PPT presentation

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Title: Multi-wavelength Semiconductor Fiber Lasers


1
Multi-wavelength Semiconductor Fiber Lasers
Lawrence R. Chen Photonic Systems
Group Department of Electrical and Computer
Engineering McGill University Montreal, Quebec,
Canada lawrence.chen_at_mcgill.ca
2
Acknowledgments
  • Reuven E. Gordon, Véronique Pagé, Dr.
    Varghese Baby
  • Serge Doucet, Prof. Sophie LaRochelle
  • NSERC Canada and Canadian Institute for Photonic
    Innovations
  • Anritsu Electronics, Ltd.

3
Motivation
  • Multi-wavelength optical sources have numerous
    applications
  • Optical instrumentation
  • Fiber optic sensing
  • Optical communications
  • Microwave photonics
  • Regimes of operation
  • Continuous wave
  • Mode-locked
  • Fiber-based solutions are attractive and have the
    advantage of low coupling loss to optical fiber
    systems

4
Features
  • Stable operation
  • Power
  • Wavelength
  • Broad wavelength range
  • Wavelength spacing from very large (100s of GHz)
    to very narrow (10s of GHz)
  • High output power (mW)
  • Single longitudinal mode
  • Tunable operation

5
Challenges
  • Stable, multi-wavelength operation with narrow
    wavelength spacing is difficult to achieve in
    erbium-doped fiber (EDF) due to homogeneous
    broadening
  • Cool to 77 ?K
  • Frequency-shifting
  • Polarization holeburning
  • Careful gain equalization
  • Complex cavities
  • Semiconductor optical amplifiers exhibit
    inhomogeneous linewidth broadening

6
Semiconductor Fiber Lasers
  • Use SOAs as the gain medium
  • Ring or standing-wave cavities
  • Multi-wavelength filters
  • Ideally, fiber-based such as
  • Fiber Bragg gratings
  • Mach-Zehnder interferometers
  • Tunable multi-wavelength operation
  • Tunable wavelength filters (lasing wavelengths
    are individually tunable)
  • Tunable comb filters (lasing wavelengths have
    equally increased or decreased wavelength spacing)

7
SFL with a Fabry-Pérot Filter
  • First demonstration of a multi-wavelength
    semiconductor fiber ring laser
  • Serial SOAs used to increase lasing bandwidth

38 wavelengths with 50 GHz channel spacing
N. Pleros et al, IEEE PTL, vol. 14, pp. 693-695
(2002)
8
SFL with Sampled FBG
  • First demonstration of multi-wavelength lasing in
    a ring laser using a sampled FBG

Sampled FBG periodic comb filter with wavelength
spacing set by the sample period P
J. Sun et al, IEEE PTL, vol. 14, pp. 750-752
(2002)
9
SFL with Sampled FBG in HiBi Fiber
  • Switchable operation demonstrated with a sampled
    FBG in HiBi fiber

Due to the different effective indices of the x
and y polarizations in the HiBi fiber, each
polarization will have its own reflection peak
B.-A. Yu et al, IEE EL, vol. 39, pp. 649-650
(2003)
10
SFL with a Mach-Zehnder Interferometer
  • gt 40 wavelengths with 0.5 nm spacing and tunable
    operation
  • VOA used to control lasing wavelengths by
    saturating the SOA

VOA 3 dB
VOA 8.5 dB
VOA 14 dB
F. W. Tong et al, IEE EL, vol. 40, pp. 594-595
(2004)
11
SFL with a PLC-Based Delayed Interferometer
  • 75 wavelengths with 40 GHz spacing

DI spectral response
Laser output
H. Dong et al, IEEE PTL, vol. 17, pp. 303-305
(2005)
12
SFL with a Fabry-Pérot Filter
  • 50 wavelengths with 50 GHz spacing at 1300 nm

H. Chen, Opt Lett, vol. 30, pp. 619-621 (2005)
13
SFL with a Linear Optical Amplifier
  • LOA (gain-clamped SOA)
  • Reduced transients compared to conventional SOA
    which results in improved power stability

K. K. Kureshi, IEEE PTL, vol. 17, pp. 1611-1613
(2005)
14
SFL with a Linear Optical Amplifier
  • 20 wavelengths with 100 GHz spacing using
    multi-wavelength thin film etalon filter

Sample laser output
15
SFL with a Linear Optical Amplifier
  • Comparison of power stability

SOA
LOA
16
HiBi Fiber Loop Mirror Comb Filter
  • Fiber loop mirror incorporating a segment of HiBi
    fiber
  • Coupler splits input beam into two
    counter-propagating beams and recombines them
    after traveling through fiber loop
  • Birefringence (?n) produces a phase difference
    (??) between the fast and slow components of a
    propagating beam
  • Reflectivity of FLM depends on
  • this phase difference
  • where
  • Periodicity given by

Fang and Claus, Opt Lett, vol. 20, pp. 2146-2148
(1995) Dong et al., Electron. Lett., vol. 36, pp.
1609-1610 (2000)
17
SFL with HiBi-FLM
  • Interleaved waveband switching
  • 17 wavelengths with 100 GHz spacing, bands
    separated by 50 GHz

Comb filter response
Laser output response
Y. W. Lee et al, IEEE PTL, vol. 16, pp. 54-56
(2004)
18
Digitally Programmable HiBi-FLM
  • State of the switches determines the total length
    of HiBi fiber in the FLM
  • If the HiBi fiber segments have equal lengths L,
    the total length can be varied digitally between
    L, 2L, NL
  • Thus, the wavelength separation can also vary
    digitally between
  • As a simple demonstration, we use two fiber
    segments and one switch
  • For the cross-state,
  • For the bar state,

L. R. Chen, IEEE PTL, vol. 16, pp. 410-412 (2004)
19
Digitally Programmable HiBi-FLM
  • Results
  • Switch in cross-state
  • L 1.99 m ? ?? ? 3.2 nm
  • insertion loss ? 7 dB
  • Switch in bar state
  • L 3.98 m ? ?? ? 1.6 nm
  • insertion loss ? 10 dB

After changing the state of the switch, may need
to adjust PC to optimize contrast
20
Tunable SFL
  • Switch in cross-state
  • Switch in bar-state
  • 6 lasing wavelengths with
  • minimum SNR 40 dB
  • linewidths lt 0.12 nm
  • 11 lasing wavelengths with
  • minimum SNR 36 dB
  • linewidths lt 0.15 nm

21
Tunable SFL
  • Stability repeated scans of output spectra
  • Output power fluctuations lt 1.5 dB
  • Wavelength variations lt 0.05 nm

Switch in cross-state (?? 3.2 nm)
Switch in bar state (?? 1.6 nm)
22
Waveband-Switchable SFL
  • Phase modulator in HiBi-FLM allows tuning of the
    comb filter transfer function
  • Used to vary amount of birefringence in the loop
  • Shift in comb response but comb spacing is
    unchanged
  • 21 wavelengths with 100 GHz spacing

M. P. Fok et al, IEEE PTL, vol. 17, pp. 1393-1395
(2005)
23
SFL with HiBi-FLM and Hybrid SOA-EDFA Gain Medium
  • Increased wavelength range of operation

Y.-G. Han et al, IEEE PTL, vol. 17, pp. 989-991
(2005)
24
FBG-Based Fabry-Pérot
  • Superimposed chirped FBGs can be used to create a
    high-finesse FP resonator (CFPR)

R. Slavík et al, IEEE PTL, vol. 16, pp. 1017-1019
(2004)
25
SFL with a CFPR
  • Standing-wave cavity

FSR 25 GHz
V. Baby et al, CIPI Project IT2
26
SFL with a CFP Resonator
  • Tunable operation by adjusting PC in HiBi-FLM

27
SFL with a CFP Resonator
  • 35 wavelengths with 25 GHz spacing

9 dB
28
Application of Multi-wavelength SFL
  • Photonic code conversion in packet-switched
    networks with code-based processing (CIPI Project
    IT2)

R. E. Gordon and L. R. Chen, IEEE PTL, vol. 18,
pp. 586-588 (2006)
29
Photonic Code Conversion Schematic and Principle
ON
Input Code i
?i1
CONTROL ARM
4 x 1
?i2
VOA
MOD
EDFA
PCC
?i3
?i4
SOA1
SOA2
OCA
Isolator
SAT
PC1
PC2
OCB
90
RING
10
OFF
PD Rx
AWG
Output Code j
Loop Mirrors
?j1
?j2
?j3
?j4
30
Photonic Code Conversion Schematic and Principle
OFF
Input Code i
?i1
CONTROL ARM
4 x 1
?i2
VOA
MOD
EDFA
PCC
?i3
?i4
SOA1
SOA2
OCA
Isolator
UNSAT
PC1
PC2
OCB
90
RING
10
ON
PD Rx
AWG
Output Code j
Loop Mirrors
?j1
?j2
?j3
?j4
31
PCC Results
32
Applications of Tunable Multi-wavelength SFL
  • Measuring chromatic dispersion based on
    time-of-flight

V. Pagé and L. R. Chen, Opt Commun (to appear,
2006)
33
Measuring CD based on TOF Results
  • Measurements using both wavelength spacings

34
Measuring CD based on TOF Results
  • CD measurements for both wavelength spacings and
    comparison to standard phase-shift technique

35
Applications of Tunable Multi-wavelength SFL
  • Tunable photonic microwave filter
  • Microwave filter response (using 9.5 km of SMF as
    dispersive medium)

L. R. Chen and V. Pagé, IEE EL, vol. 41, pp.
1183-1184 (2005)
36
Summary
  • Using SOA as a gain medium allows for
  • Stable, multi-wavelength operation at room
    temperature
  • Narrow wavelength spacings (25 GHz demonstrated)
  • Relatively simply implementation
  • Issues for further study
  • Power equalization
  • Single longitudinal mode operation
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