Integrated Waveguide Modulator - Laser Diode (IWM-LD)

Integrated Waveguide Modulator - Laser Diode (IWM-LD)


The past decade witnessed the rapid development of LED based solid-state lighting (SSL) and visible light communication (VLC) systems. However, the relatively low bandwidth (tens or hundreds of MHz) in LEDs limits the data transmission rate. The advent of GaN-based laser-diode offers Gbit/s data rates with high optical power. However, the current approach based on direct-current modulation of c-plane laser diodes suffers from large modulation voltage, transient-heating effect and RC delay.​By seamlessly combining waveguide-modulator and laser diode emitting at 448 nm on semipolar-plane substrate, which has considerably reduced polarization fields, a small-footprint, high-speed, low power-consumption device having the SSL-VLC dual-functionalities was demonstrated. Our device shows a high modulation efficiency of 2.68 dB/V, large modulation bandwidth of > 1GHz with a low operating voltage range of 3.5 V. Our approach enables the platform for high data-rate SSL-VLC dual-function lamps for eventual realization of smart-lighting and internet-of-things.
  • Voltage modulation (QCSE-based).
  • Small area (reduced capacitance).
  • Small modulation current (Suppressed transient heating and reduced switching power).

Our device exhibits a high modulation efficiency (Ron/off/ΔV) of 2.68 dB/V, which is more than double in reported c-plane modulators (~ 1.11 dB/V).


High-modulation-efficiency, integrated waveguide modulator-laser diode at 448 nm
Chao Shen, Tien Khee Ng, John T. Leonard, Arash Pourhashemi, Hassan M. Oubei, Mohd S. Alias, Shuji Nakamura, Steven P. DenBaars, James S. Speck, Ahmed Y. Alyamani, Munir M. Eldesouki, and Boon S. Ooi
ACS Photonics, 3(2), pp. 262–268 (2016)

DOI: 10.1021/acsphotonics.5b00599

HDL: 10754/595377