Multi-rate DPSK optical transceivers for free-space applications

Caplan, D.O.; Carney, John; Fitzgerald, John J.; Gaschits, Igor D.; Kaminsky, Richard D.; Lund, G.; Hamilton, Scott A.; Magliocco, R. J.; Murphy, Robert J.; Rao, Hemonth G.; Spellmeyer, Neal; Wang, J. P.

doi:10.1117/12.2057570

Cited by 16 publications

(16 citation statements)

References 40 publications

(64 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This stems from several reasons including a power-independent decision threshold, a 3 dB better communications sensitivity compared to intensity-based modulation formats such as on-off keying and binary-pulse-position modulation, and implementation with commonly available components. [5][6][7] In addition, rate-adaptive modem designs have been demonstrated [8][9][10][11][12] which can be used to optimize system performance over the highly variable channel associated with mobile free-space optical communication links. [13][14][15] Some of these designs have been implemented with near quantum-limited performance.…”

Section: Importance Of Frequency Stabilitymentioning

confidence: 99%

Frequency stabilization of laser diodes in an aggressive thermal environment

et al. 2015

View full text Add to dashboard Cite

Mobile free-space laser communication systems must reconcile the requirements of low size, weight, and power with the ability to both survive and operate in harsh thermal and mechanical environments. In order to minimize the aperture size and amplifier power requirements of such systems, communication links must exhibit performance near theoretical limits. Such performance requires laser transmitters and receiver filters and interferometers to maintain frequency accuracy to within a couple hundred MHz of the design frequency. We demonstrate an approach to achieving high frequency stability over wide temperature ranges by using conventional DFB lasers, tuned with TEC and current settings, referenced to an HCN molecular frequency standard. A HCN cell absorption line is scanned across the TEC set-point to adjust the DFB laser frequency. Once the center of the line is determined, the TEC set-point is offset as required to obtain frequency agility. To obtain large frequency offsets from an HCN absorption line, as well as continuous laser source operation, a second laser is offset from the reference laser and the resulting beat tone is detected in a photoreceiver and set to the desired offset using a digital frequency-locked loop. Using this arrangement we have demonstrated frequency accuracy and stability of better than 8 MHz RMS over an operational temperature range of 0ºC to 50º C, with operation within minutes following 8 hour soaks at -40º C and 70º C.

show abstract

Section: Importance Of Frequency Stabilitymentioning

confidence: 99%

Frequency stabilization of laser diodes in an aggressive thermal environment

et al. 2015

View full text Add to dashboard Cite

show abstract

“…The multi-rate DPSK modem design uses a burst-mode architecture and a variety of self-test functionality to offer flexibility and robust operation for challenging free-space environments [1][2][3][4][5][6] . In order to successfully test the operation of this modem, we developed advanced test and diagnostic capabilities which can be easily reconfigured to support the various modem functional modes.…”

Section: Introductionmentioning

confidence: 99%

“…The multi-rate burst-mode architecture enables flexible communications across many channel conditions. The channel data rate is reduced by creating a burst-mode waveform with data bursts followed by "off" time during which no optical pulses are transmitted [3][4][5] . Since the transmitter power amplifier is an average-power-limited device, reductions in the duty cycle of the transmit waveform results in an increase in peak power at the output of the transmitter 9 .…”

Section: Introductionmentioning

confidence: 99%

Performance and qualification of a multi-rate DPSK modem

et al. 2014

Self Cite

View full text Add to dashboard Cite

Recently, we demonstrated a multi-rate DPSK modem with high-sensitivity over a wide dynamic range, which can significantly benefit performance and cost of NASA's Laser Communication Relay Demonstration. This increased flexibility, combined with the need to verify robust operation under challenging free-space environmental conditions, results in a large number of operational states which must be accurately and thoroughly tested. To support this, we developed test and diagnostic capabilities that can be easily reconfigured to assess modem performance across a wide range of data rates and operational modes. These capabilities include internal self-test modes in which test waveforms can be directed from the transmitter into the receiver to determine modem communications performance. We used these self-test capabilities to demonstrate robust performance in realistic environments during thermal-vacuum, shock/vibration, and EMI/EMC testing.

show abstract

“…The loopback receiver has utility beyond laboratory or ground-based testing, [12][13][14]16 since a variant of this receiver can be integrated into the flight design to provide a built-in self-test (BIST) functionality. With this configuration, BIST provides important diagnostic information about the health of the optical transmitter.…”

Section: Built-in Self-testmentioning

confidence: 99%

“…[12][13][14] This receiver consists of a comparator-based analog front-end that converts the input analog electrical signal into digital for processing by the FPGA. A digital to analog converter (DAC) is used to generate a threshold voltage that can be adjusted to optimize the error rate.…”

Section: Loopback Receiver and End-to-end Link Validationmentioning

confidence: 99%

Implementation and validation of a CubeSat laser transmitter

2016

Self Cite

View full text Add to dashboard Cite

The paper presents implementation and validation results for a CubeSat-scale laser transmitter. The master oscillator power amplifier (MOPA) design produces a 1550 nm, 200 mW average power optical signal through the use of a directly modulated laser diode and a commercial fiber amplifier. The prototype design produces highfidelity M-ary pulse position modulated (PPM) waveforms (M=8 to 128), targeting data rates > 10 Mbit/s while meeting a constraining 8 W power allocation. We also present the implementation of an avalanche photodiode (APD) receiver with measured transmitter-to-receiver performance within 3 dB of theory. Via loopback, the compact receiver design can provide built-in self-test and calibration capabilities, and supports incremental on-orbit testing of the design.

show abstract

Multi-rate DPSK optical transceivers for free-space applications

Cited by 16 publications

References 40 publications

Frequency stabilization of laser diodes in an aggressive thermal environment

Frequency stabilization of laser diodes in an aggressive thermal environment

Performance and qualification of a multi-rate DPSK modem

Implementation and validation of a CubeSat laser transmitter

Contact Info

Product

Resources

About