2020/7/31
State Key Lab on Integrated Optoelectronics
Directly Modulated DFB LDs
Applications
– Gigabit Ethernet – Metropolitan transmission – Bit rate: up to 10 Gb/s – Wavelength: 1.3 m & 1.55 m
10 Gb/s EA Modulator Integrated DFB LDs for Trunk Line Communications
Transmission length: 100 km Feature: Low power penalty (<1.5 dB) & Wide bandwidth (~14 GHz)
Limitations
– Limited bandwidth for APD detectors – Trade-off between bandwidth and efficiency for surface
illuminated p-i-n detectors
Current Trend
– Side illuminated structure Waveguide p-i-n photodiodes
2020/7/31
State Key Lab on Integrated Optoelectronics
10 Gb/s Directly Modulated DFB LDs for Metropolitan Data T
2020/7/31
Multi-range Wavelength Selectable LDs
For use in back-up & add-drop in DWDM photonic network DFB-LDs integrated with MMI coupler, SOA, and EA modulator Compact size (400 m 2840 m)
2020/7/31
State Key Lab on Integrated Optoelectronics
10 Gb/s EA Modulator Integrated DFB LDs
Eye Diagram
2020/7/31
BER Performance
State Key Lab on Integrated Optoelectronics
半导体光电子学
2020/7/31
Background
The Demand for More Bandwidth Internet, multimedia communications, and etc Methods to Increase System Capacity WDM (Wavelength-Division Multiplexing) OTDM (Optical Time-Division Multiplexing) Benefits of WDM techniques Flexibility and scalability for a variety of network architectures
Advantages
– Compact size – Low coupling loss – Low frequency chirping – Reduced cost – Improved reliability
2020/7/31
State Key Lab on Integrated Optoelectronics
Low-Cost Uncooled LDs
Applications
– Access network – Metropolitan transmission – Bit rate: 155 MB/s (FP-LDs) ~ 10 Gb/s (DFB-LDs)
Requirements
– Wide temperature range operation – Cost-effective structure for device fabrication – High efficiency and large tolerance for coupling output light
2020/7/31
State Key Lab on Integrated Optoelectronics
Key Devices for WDM Optical Fiber Network Systems
Light Sources
– Low-cost uncooled LDs – Directly modulated LDs – Modulator integrated DFB LDs – Wavelength tunable/selectable LDs
Wavelength Tunable vs. Wavelength Selectable
– Wavelength Tunable LDs:Based on DBR structures Compact device structure Poor reliability & Electric crosstalk at high frequency
Limitations
– Limited transmission span (< 20 km) due to large linewidth enhancement factor (> 4)
– Modulation speed is limited by carrier relaxation oscillation
into a single mode fiber
2020/7/31
State Key Lab on Integrated Optoelectronics
Uncooled Gain-Coupled DFB LDs
Stable single mode operation from - 40 to 85C Integrated beam-expander for improved coupling tolerance Gain-coupled DFB lasers with current-blocking gratings
2020/7/31
State Key Lab on Integrated Optoelectronics
Wideband Waveguide Photodiode for 40 Gb/s Systems
Monolithic receiver composed of multimode waveguide p-i-n photodiode and a HEMT distributed amplifier
2020/7/31
State Key Lab on Integrated Optoelectronics
Multi-Range Wavelength Selectable LD Arrays for DWDM Systems
15 nm/chip wavelength selectable range
Wavelength Tunable/Selectable LDs
Advantages
– Ability to restore failed channels – Reduced transmitter cost – Increased flexibility for future network managing
WDM techniques are the backbone of modern optical fiber networks
2020/7/31
State Key Lab on Integrated Optoelectronics
2020/7/31
State Key Lab on Integrated Optoelectronics
High-Speed Photodetectors
SOA and Wavelength Converter
AWG and Related
2020/7/31
State Key Lab on Integrated Optoelectronics
2020/7/31
State Key Lab on Integrated Optoelectronics
2020/7/31
State Key Lab on Integrated Optoelectronics
BER Characteristics
State Key Lab on Integrated Optoelectronics
EA Modulator Integrated DFB LDs
Applications
– Trunk line transmission – Bit rate: 2.5 Gb/s ~ 40 Gb/s
– Wavelength Selectable LDs: Based on DFB LD arrays Relatively complicated device structure Improved reliability and wavelength stability
2020/7/31
State Key Lab on Integrated Optoelectronics
Wavelength & Threshold current
Lasing Spectra
2020/7/31
State Key Lab on Integrated Optoelectronics
High-Speed Photodetectors
Conventional Configurations