scholarly journals Electrically Parallel Three-Element 980 nm VCSEL Arrays with Ternary and Binary Bottom DBR Mirror Layers

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 397
Author(s):  
Nasibeh Haghighi ◽  
James Lott
Keyword(s):  
Free Space ◽  
Low Cost ◽  
Cavity Surface ◽  
Free Space Optical ◽  
Optical Links ◽  
Sensing Applications ◽  
Free Data ◽  
Starting Point ◽  
Emitting Lasers ◽  
Vcsel Arrays

To meet the performance goals of fifth generation (5G) and future sixth generation (6G) optical wireless communication (OWC) and sensing systems, we seek to develop low-cost, reliable, compact lasers capable of sourcing 5–20 Gb/s (ideally up to 100 Gb/s by the 2030s) infrared beams across free-space line-of-sight distances of meters to kilometers. Toward this end, we develop small arrays of electrically parallel vertical cavity surface emitting lasers (VCSELs) for possible future use in short-distance (tens of meters) free-space optical communication and sensing applications in, for example, homes, data centers, manufacturing spaces, and backhaul (pole-to-pole or pole-to-building) optical links. As a starting point, we design, grow by metal–organic vapor phase epitaxy, fabricate, test, and analyze 980 nm top-emitting triple VCSEL arrays. Via on-wafer high-frequency probe testing, our arrays exhibit record bandwidths of 20–25 GHz, optical output powers of 20–50 mW, and error-free data transmission at up to 40 Gb/s—all extremely well suited for the intended 5G short-reach OWC and sensing applications. We employ novel p-metal and top mesa inter-VCSEL connectors to form electrically parallel but optically uncoupled (to reduce speckle) arrays with performance exceeding that of single VCSELs with equal total emitting areas.

Source Synchronous Double Data Rate (DDR) Parallel Optical Interconnects

2003 ◽  
Author(s):  
Ping Gui ◽  
Fouad Kiamilev ◽  
Xiaoqing Wang ◽  
Michael McFadden ◽  
Charlie Kuznia ◽  
...  
Keyword(s):  
Free Space ◽  
High Speed ◽  
Flip Chip ◽  
Data Rate ◽  
Cavity Surface ◽  
Cmos Process ◽  
Free Space Optical ◽  
Optical Links ◽  
Parallel Optical Interconnects ◽  
Emitting Lasers

Double data rate (DDR) signaling is widely used in electrical interconnects to eliminate clock recovery and to double communication bandwidth. This paper describes the design of a parallel optical transceiver integrated circuit (IC) that uses source-synchronous, DDR optical signaling. On the transmit side, two 8-bit electrical inputs are multiplexed, encoded and sent over two high-speed optical links. On the receive side, the procedure is reversed to produce two 8-bit electrical outputs. Our IC integrates analog Vertical Cavity Surface Emitting Lasers (VCSEL), drivers and optical receivers with digital DDR multiplexing, serialization, and deserializaton circuits. It was fabricated in a 0.5-micron Silicon-on-Sapphire (SOS) CMOS process. Linear arrays of quad VCSELs and photodetectors were attached to our transceiver IC using flip-chip bonding. A free-space optical link system was constructed to demonstrate correct IC functionality. The test results show successful transceiver operation at a data rate of 500 Mbps with a 250 MHz DDR clock, achieving a gigabit of aggregate bandwidth. While our DDR scheme is well suited for low-skew fiber-ribbon, free-space and waveguide optical links, it can also be extended to links with higher skew with the addition of skew-compensation circuitry. To our knowledge, this is the first demonstration of parallel optical transceivers that use source-synchronous DDR signaling.

scholarly journals A two-way 224-Gbit/s PAM4-based fibre-FSO converged system

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Hai-Han Lu ◽  
Chung-Yi Li ◽  
Wen-Shing Tsai ◽  
Poh-Suan Chang ◽  
Yan-Yu Lin ◽  
...  
Keyword(s):  
Amplitude Modulation ◽  
Free Space ◽  
Single Mode ◽  
Pulse Amplitude ◽  
Cavity Surface ◽  
Pulse Amplitude Modulation ◽  
Free Space Optical ◽  
Surface Emitting Lasers ◽  
Vertical Cavity Surface ◽  
Emitting Lasers

AbstractA two-way 224-Gbit/s four-level pulse amplitude modulation (PAM4)-based fibre-free-space optical (FSO) converged system through a 25-km single-mode fibre (SMF) transport with 500-m free-space transmission is successfully constructed, which adopts injection-locked vertical-cavity surface-emitting lasers with polarisation-multiplexing mechanism for a demonstration. Compared with one-way transmission, two-way transmission is an attractive architecture for fibre-FSO converged system. Two-way transmission over SMF transport with free-space transmission not only reduces the required number of fibres and the setups of free-space transmission, but also provides the advantage of capacity doubling. Incorporating dual-wavelength four-level pulse amplitude modulation (PAM4) modulation with polarisation-multiplexing mechanism, the transmission capacity of fibre-FSO converged system is significantly enhanced to 224 Gbit/s (56 Gbit/s PAM4/wavelength × 2-wavelength × 2-polarisation) for downlink/uplink transmission. Bit error rate and PAM4 eye diagrams (downstream/upstream) perform well over 25-km SMF transport with 500-m free-space transmission. This proposed two-way fibre-FSO converged system is a prominent one not only because of its development in the integration of fibre backbone with optical wireless extension, but also because of its advantage in two-way transmission for affording high downlink/uplink data rate with good transmission performance.

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