Title: MidInfrared Light Sources Based on Difference Frequency Generation in DirectBonded PeriodicallyPoled
1Mid-Infrared Light Sources Based on Difference
Frequency Generationin Direct-Bonded
Periodically-Poled LiNbO3 Ridge Waveguides
MIOMD-?, Lancaster, Sep. 11-14
H. Suzuki, O. Tadanaga, T. Yanagawa, Y.
Nishida H. Miyazawa, K. Magari and M. Asobe NTT
Photonics Laboratories NTT Corporation
(hiroyuki_at_aecl.ntt.co.jp)
2Outline
- Background
- Key device High-efficiency PPLN waveguides
- Application to visible laser sources
- Characteristics of mid-IR DFG light sources in
the 2-3mm regions - Demonstration of gas absorption measurements
- Future plan
3High-efficiency wavelength converter for WDM
applications
Device structure
0-dB DWDM signal conversion
40Gb/sx8ch conversion by multi-PPLN WC
Telecom applications ? Non-telecom applications
4Construction of laser light sources
Telecom LD1
l3 generation by SFG or DFG in PPLN WG
Telecom LD2
PPLN WG
Desired laser light generation from selected?1
?2 Sum-frequency generation (SFG) _at_
visible Difference-frequency generation (DFG) _at_
mid-IR
5560-590 nm light sourcesusing sum-frequency
generation
Output wavelength 560nm 0.98mm1.3mm 590nm
1.06mm1.3mm
- Output power
- gt10mW for CW
- gt5mW for direct modulation
- Direct modulation capability
- Low noise
6Mid-infrared DFG light source based on PPLN
waveguide
- Telecom LD pumped
- mid-IR light generation
- between 2 and 5 mm
-
- gtRT CW operation
-
- Widely tunable
- _at_ 2.3-mm range
7Absorption intensity of various gases
Target wavelengths
8Direct bonded ridge waveguide
Zn-doped or non-doped LN substrate
Diamond blade
Electrical poling
Polarization
Direct bonding
Bonded LN/LT wafer
LT or Mg-doped LN substrate
lt10 mm
Lapping and polishing
Waveguide fabrication using dicing saw
Photograph of waveguide cross-section
High damage resistance Long-term
reliability High conversion efficiency
Precise design
9DFG characteristics of3-mm band waveguide
DFG tuning curve
L 28.4 mm L50 mm RT
Pump NdYLF 10 mW Signal Tunable LD 1 mW
Conversion efficiency 40 /W Output 0.26-mW
with 11-mW pump and 66-mW signal
10CH4 (_at_ 3.3 mm) detection setup
11CH4 absorption spectrum
CH4 gas cell 10 Torr, 20cm (CaF2 windows)
Reference cell 10-5 Torr, 20cm (CaF2 windows)
12Broad-band phase-matching_at_ 2.3 mm
lp 0.94 mm Wide tuning range _at_ 2.3 mm
13Simulated DFG characteristicsin a 5 cm-long bulk
sample
14DFG tuning curve
DFG characteristics of fabricated 2mm-band
waveguide
Signal power vs Output power
L 25.60 mm L50 mm RT
3-dB bandwidth _at_ RT 100 nm Conversion
efficiency 100 /W Output gt0.4 mW
15CO (_at_ 2.4 mm) detection setup
16CO isotopomer absorption spectrum
12CO / buffer gas cell 300 Torr, 20cm
(anhydros SiO2 windows) 13CO / buffer gas
cell 300 Torr, 20cm (anhydros SiO2 windows)
12CO (100Torr)
13CO (100Torr)
Reference gas cell 300 Torr, 40cm
17CO ro-vibration absorption spectra
12CO (100 Torr, 20cm)
13CO (100 Torr, 20cm)
18Assignment of 12CO ro-vibration absorption lines
P-branch
R-branch
19Signal bandwidth vs Pump wavelength
20ppm-level CO2 detection in air _at_ 2.7 mm
4 ppm
Multi-pass cell Pump laser _at_ 0.98 mm
21Mid-IR PPLN waveguide module
PPLN waveguide module
PPLN waveguide
22Summary
- Laser diode pumped mid-IR light sources
- using DFG in direct bonded PPLN waveguide.
-
- Mid-IR light generated in the 2- and 3-mm
regions. - Conversion efficiency 40100 /W.
- Output mW level
-
- Absorption measurements demonstrated
- for CH4, CO isotomomers and CO2.
-
- Mid-IR PPLN waveguide being developed.