High-brightness all semiconductor laser at 1.57 μm for space-borne lidar measurements of atmospheric carbon dioxide: device design and analysis of requirements

Abstract

The availability of suitable laser sources is one of the main challenges in future space missions for accurate measurement of atmospheric CO 2 . The main objective of the European project BRITESPACE is to demonstrate the feasibility of an all-semiconductor laser source to be used as a space-borne laser transmitter in an Integrated Path Differential Absorption (IPDA) lidar system. We present here the proposed transmitter and system architectures, the initial device design and the results of the simulations performed in order to estimate the source requirements in terms of power, beam quality, and spectral properties to achieve the required measurement accuracy. The laser transmitter is based on two InGaAsP/InP monolithic Master Oscillator Power Amplifiers (MOPAs), providing the ON and OFF wavelengths close to the selected absorption line around 1.57 µm. Each MOPA consists of a frequency stabilized Distributed Feedback (DFB) master oscillator, a modulator section, and a tapered semiconductor amplifier optimized to maximize the optical output power. The design of the space-compliant laser module includes the beam forming optics and the thermoelectric coolers.The proposed system replaces the conventional pulsed source with a modulated continuous wave source using the Random Modulation-Continuous Wave (RM-CW) approach, allowing the designed semiconductor MOPA to be applicable in such applications. The system requirements for obtaining a CO 2 retrieval accuracy of 1 ppmv and a spatial resolution of less than 10 meters have been defined. Envelope estimated of the returns indicate that the average power needed is of a few watts and that the main noise source is the ambient noise.

A Review of High-Power Semiconductor Optical Amplifiers in the 1550 nm Band

“…The SOA is extremely competitive, whether it is used as a MOPA amplifier or directly used as an optical amplifier for LiDAR instead of the EDFA. Generally, it is suitable for reducing the cost and volume as much as possible while increasing the laser power to achieve longer distance ranging, although there are still many performance indicators that need to be optimized [119][120][121]. In TOF technology, the SOA needs to exhibit higher gain and saturation output power, as well as a faster gain-recovery speed, to meet the amplification requirements of high-frequency-pulsed-laser signals.…”

Monolithic integration of a high power semiconductor Master Oscillator Power Amplifier

“…8b shows the optical modulation amplitude (OMA) and the Extinction Ratio (ER) as a function of the modulation amplitude Vpp. At 12.5 MHz a maximum OMA of ~ 170 mW with an ER of ~ 42 dB is obtained for Vpp = 20 V. This modulation results are encouraging for the application of the device as laser source for the detection of atmospheric CO 2 by random modulation-continuous wave differential absorption lidar (RMCW DIAL) [3].…”

Emission characteristics of 1.5 um monolithically integrated master oscillator power amplifiers

“…The objective of the RANGER project was to implement a lidar system to measure distances using a high brightness semiconductor laser. BRITESPACE was conceived with the aim of designing, fabricating and validating a semiconductor laser for the detection of carbon dioxide in future Earth observation missions [37]. The proposed system was an IPDA lidar based on an integrated semiconductor MOPA.…”

“…-on-line 0.1 MHz -off-line 100 MHz Table 5.1: General requirements of the BRITESPACE CW-RM IPDA lidar system for measuring carbon dioxide in the atmosphere [37]. ( * ) Dry-air volume mixing ratio of CO 2 .…”