Semiconductor Optical Amplifiers in Avionics C Michie W

Semiconductor Optical Amplifiers in Avionics C Michie, W Johnstone , I Andonovic , E Murphy , H White, A Kelly

Semiconductor Optical Amplifiers in Avionics • Significant advantages within Avionics context from use of optical communications networks • bandwidth, EMI, significant weight savings • Current systems limited to point, multimode • This work • Learn from terrestrial communications using COTS • Focus on PONs – cost is critical • Strategies towards WDM – minimal component inventory • Key operational consideration • Extended temperature range

Long Haul; DWDM systems maximise fibre bandwidth usage TXλ 1 TXλ 2 TXλX TXλN 40 wavelengths, 200 GHz spacing 10, 40, 100+ Gbit/channel

Long Haul; DWDM systems maximise fibre bandwidth usage • Wavelength specific transmitters – single wavelength, DFB – Temperature regulated • Many wavelengths – inventory issues for Avionic system • Temperature Control – increased power consumption • Expensive for Avionics – not a flier!

Passive Optical Networks • • High bandwidth Access solutions Cost is critical – minimise number of components Minimise manufacturing specification Operate without cooling if possible • Reflective Semiconductor Based Optical Amplifiers – RSOA – transmitter and amplifier using same component

RSOAs as transmitters P λ BLS User end CS- RSOA

RSOAs as transmitters P λ CS-RSOA P CS-RSOA Broad Band BLS Source CS-RSOA User

Avionics Link • Simple link – 500 m, 1 Gbit/s • Single Broad band seed source – might need two ? • Multiplexer, de-multiplexer • Minimal cooling/heating

BLS 0. 6 d. B 0. 8 d. B 3. 5 d. B 0. 6 d. B Rx Rx Rx Tx RSOA Fibre Link Tx RSOA Rx Tx RSOA Rx Rx Rx Fibre Link

RSOA Design In. P: In. Ga. As. P Buried Heterostructure Lateral Waveguide Tapers Tensile Bulk High back refectivity 0. 88 Front facet AR coated RSOA in TO

TO-packaged S-band RSOA parametric tests Standard tests at 25ºC and 80 m. A

Dynamic Range • Psat ~ 5 d. Bm, Gain > 20 d. B • so we need -15 d. Bm input to saturate • Can get 0 d. Bm/nm from COTS sources • -5 d. Bm/nm is obtainable with lower power module – NB the above module needs to be cooled but it should be the only component within the system • To get 12 d. B dynamic range (allows 3 d. B plus of margin) we can allow gain/Psat drop with temperature

RSOA modulation experiments TO packaged devices on ETS evaluation board 50 m. A DC bias, 60 m. A modulation S band RSOA, CW injection at 1465 – 1530 nm Stage temperature 25°C Modulation at 1. 25 Gbps data rate with 211 -1 PRBS bit pattern The Rx - APD photoreceiver with limiting amplifier

Sensitivity, Output Power, Gain and Path Loss Capability at 1490 nm and 25ºC ~30 d. B return path loss capability at -20 d. Bm input

Sensitivity, Output Power, Gain and Path Loss Capability at 1580 nm and 25ºC

Sensitivity, Output Power, Gain and PLC versus Wavelength at 25ºC -20 d. Bm CW input power and 25ºC stage temperature Eye diagram at 1490 nm

S, C and L band performance S-band device C-band device

RSOA with Broadband light source

Path Loss Capability TLS, Bl. S

High Temperature RSOA Design Al. In. Ga. As Ridge Waveguide Single Polarisation High back refectivity 0. 88 Front facet AR coated 0. 01% RSOA in TO

Temperature Performance of RSOA Tuneable Laser Variable Attenuator RSOA Temperature Controlled Mount Optical Spectrum Analyser Evaluate Gain, NF, Psat as a function of temperature. Enables prediction of performance (Power budget for BER 10 -9)

Packaged BH Temperature Characterisation

Chip on Carrier Ridge Temperature Characterisation

Temperature Characterisation

Conclusions • WDM PONs enabled by RSOAs – TO packaged polarisation insensitive S band RSOA – ~1 d. B penalty at 1. 25 Gbit/s compared to commercial M-Z modulator • High Temperature Operation Al. In. Ga. As active region – – Ridge waveguide design due to oxidation Single polarisation Potential to increase operating temperature to > 70 C Much reduced cooling requirement