1. Broadband Lateral Tapered Structures for Improved Bandwidth and Loss Characteristics for All-Optical Wavelength Converters
Xuejin Yan, Joe Summers, Wei Wang, Marcelo Davanco, Wenbin Zhao, Milan Masanovic, Vikrant Lal, and Daniel Blumenthal
Electrical and Computer Engineering University of California at Santa Barbara
Good morning, my name is Xuejin Yan and My topic is

2. Summary of Work
Objective: Develop building blocks to extend tuning range and decrease insertion loss of SOA XPM tunable wavelength converter to 30nm tuning range at 1.55m wavelength.
Approach: Monolithically Integrate SOA wavelength converter with Mach-Zehnder structure with tunable laser using based-InP material.
Major accomplishments:
1) Designed new type of broadband splitter/combiner for WC.
2) Active/passive structures have been designed for same structures.
2) Splitter loss was measured to be better than MMI and Y-splitter over a wavelength range of 100nm.
3) Active XGM was demonstrated using this design.
4) A TWC has been designed and preliminary measurements are being taken.
5) low reflection and low loss coupling techniques have been designed and fabricated: (i) a window design and (ii) a tapered mode converter
Here is the summary of the work we did

3. Outline
Mach-Zehnder SOA wavelength converter with new waveguide structure.
The splitter with lateral tapers
The vertical coupler at the interface of active to passive waveguide
The mode-shape converter with lateral taper and InP windows
XGM results (first stage of wavelength conversion)
Tunable wavelength converter(WC with integrated tunable laser).
The structure of the TWC
Progress for TWC
C Future work
Here is my outline,

4. The picture of WC
Here is the picture of the wavelength converter( XPM and XGM )

5. Splitter and combiner Waveguide layer InP Substrate
This is the structure of the splitter. The three waveguides are tapered laterally in the coupling region. The lower pictures are the simulation results of BPM.

6. Wavelength sensitivity of the splitter
Its advantages are low loss and very low wavelength sensitive. This curve has shown its these characteristics.

7. The picture of the splitter

8. Near Field Image of Splitter
Distance between two spots is 250 m

9. The spectrum of the splitter with integrated SOA

10. Active to passive vertical transformer
Active layer
InP etching stop layer
Waveguide layer
InP Substrate

11. The Vertical Coupler

12. InP window and mode-shape converter
Lateral taper
InP window
InP Substrate

13. The Function of InP Window

14. Near Field Image of Splitter with 50mm InP Window

15. Gain Suppression of SOA
Input light
Output light

16. 2.5GHz XGM eye diagram
Probing wavelength =1560nm, pumping wavelength =1570nm.

17. 5.0GHz XGM Eye Diagram
Probing wavelength =1560nm, pumping wavelength =1570nm.

18. Progress for TWC
SSG-DBR laser has been integrated into WC to reduce coupling loss
Splitter dimensions have been increased to ease fabrication
The first device of TWC has been fabricated

19. Wavelength Converter with Integrated SSG-DBR Laser

20. Future Work Measure and characterize the new TWC devices
Optimize the processing and design of TWC
Provide a high quality TWC device