Integrated Coherent Tunable Laser (ICTL) With Ultra-Wideband Wavelength Tuning and Sub-100 Hz Lorentzian Linewidth

Paul A Morton,Christopher D Morton,Jacob B Khurgin,Joel Guo,Michael J Morton,Jon Peters,John E Bowers,Minh Tran,Chao Xiang

doi:10.1109/jlt.2021.3127155

Abstract

This paper describes the design, fabrication, and record performance of a new class of ultra-wideband wavelength tuning, ultra-low noise semiconductor laser, the Integrated Coherent Tunable Laser (ICTL). The ICTL device is designed for, and fabricated in, a CMOS foundry based Silicon Photonics platform, utilizing heterogeneous integration of III-V material to create the integrated gain section of the laser–enabling high-volume mass-market manufacturing at low cost and with high reliability. The ICTL incorporates three or more ultra-low loss micro-ring resonators, with large ring size, in a Sagnac loop reflector geometry, creating exceptional laser reflector performance, plus an extended laser cavity length that enables highly-coherent output; ultra-low linewidth and phase noise. This paper describes record integrated laser performance; 118 nm wavelength tuning, covering S-, C- and L-bands, with Lorentzian linewidth <100 Hz, and with excellent relative intensity noise (RIN) of ≤ −155 dBc/Hz. The remarkable performance of the ICTL device, coupled with the high volume/low cost capability of the Silicon Photonics platform enables next-generation applications including ultra-wideband WDM transmission systems, fiber-optic and medical-wearable sensing systems, and automotive FMCW LiDAR systems utilizing wavelength scanning.

Highlights

High-performance lasers are key components for a wide range of communications, sensing, and RF photonics applications
Many applications require lasers that operate over a wide wavelength range, e.g. ultra-wide band (UWB) wavelength division multiplexed (WDM) systems operating across S, C- and L-Bands [2], or in systems leveraging ultra-wideband wavelength tunability, e.g. automotive LIDAR using wavelength for scanning [3], where the wavelength tuning range is paramount
This paper describes a laser design that addresses all of these requirements; high power, ultra-low Frequency Noise (FN) and Lorentzian linewidth, ultra-wideband wavelength tuning, and extremely low relative intensity noise (RIN) [4]

Summary

INTRODUCTION

High-performance lasers are key components for a wide range of communications, sensing, and RF photonics applications. Applications currently dominated by expensive, bulky, powerhungry solid state and fiber lasers can be addressed by integrated, ultra-low linewidth semiconductor lasers with the benefits of reduced size, weight, power consumption and cost (SWaP-C). This paper describes a laser design that addresses all of these requirements; high power, ultra-low FN and Lorentzian linewidth, ultra-wideband wavelength tuning, and extremely low relative intensity noise (RIN) [4]. The Integrated Coherent Tunable Laser (ICTL) device is developed on a CMOS Foundry compatible Silicon Photonics platform that is enabled by heterogeneous integration [5], to create a high-volume, low-cost, integrated laser with unparalleled performance, that will be disruptive in many applications [6]

ICTL DESIGN

HETEROGENEOUS SILICON PHOTONICS FABRICATION

ICTL MEASUREMENTS

Findings

CONCLUSIONS