Cost-effective 1310/1550nm Dual-wavelength P2P Gb/s PMD

Transcription

1 Cost-effective 1310/1550nm Dual-wavelength P2P Gb/s PMD Hisashi (Harry) Takada Industries, Ltd. sei.co..co.jp IEEE 802.3ah St. Louis, MO, March

2 Single-wavelength vs Dual-wavelength 1. Source Laser 2. Link budget 3. Reflection 1310/1310nm Single-wavelength Uncooled 1310nm FP- LD for both directions Half-mirror loses 3dB or more at both ends, 7dB~ loss as a whole Sensitive to reflection 1310/1550nm Dual-wavelength 1310nm FP-LD at ONU 1550nm DFB at OLT (uncooled for both) Proven Thin Film Filter has little excess loss Immune to reflection 2

3 1310/1310nm Single-wavelength P2P ONU Reflection leads to RX noise OLT 1.3µm 1.3µm Tx: 1.3µm FP-LD 1.25Gb/s Rx: 1.25Gb/s pin-preamp 1.3/1.3µm Half-mirror Tx: 1.3µm FP-LD 1.25Gb/s Rx: 1.25Gbps pin-preamp 1.3/1.3µm Half-mirror Loses half the power at both ends 3

4 1310/1550nm Dual-wavelength P2P ONU Reflection is rejected by TFF OLT 1.3µm 1.5µm Tx: 1.3µm FP-LD 1.25Gb/s Rx: 1.25Gb/s pin-preamplifier 1.3/1.5µm TFF Tx: 1.5µm FP-LD 1.25Gb/s Rx: 1.25Gb/s pin-preamplifier 1.5/1.3µm TFF 4

5 Source Laser Considerations 1. Cost comparison of 1310 FP and 1550 DFB 1550 DFB is generally more expensive than 1310 FP by several dollars when the isolator is not necessary. For Gb/s 10km transmission, uncooled FP or DFB without isolator will be good enough. 2. Link budget comparison 7dB~ half-splitting loss requires higher link budget (12dB 19dB~ virtually) accordingly. This 7dB~ extra budget leads to more expensive TX and/or RX specifications. As a whole, 1550 DFB will be cheaper. 5

6 Waveform of 1.5µm m TX w/o ISOLATOR Un-isolated LD output waveform 1.25Gb/s, PN7, with 4 th B-T Filter -10degC -10degC 25degC 25degC 70degC 70degC Back to Back After 80km Transmission 6

7 Optical Reflection Effect on TX output w/o B-T Filter 1.25Gb/s PN7-7.7dB reflection After 80km Transmission -7.7dB reflection -10degC 25degC 70degC w/ isolator w/o isolator 7

8 Optical Reflection Effect on BER Bit Error Ratio After 80km Transmission -7.7dB reflection 1.25Gb/s PN7-10degC 2B-5 T=-10 25degC 70degC 2R-5 T= km 80km-7.7dB Optical Input Power (dbm) Bit Error Ratio B-5 T=25 80km- 80km-7.7dB Optical Input Power (dbm) Bit Error Ratio No reflection Penalty 80km 80km-7.7dB Optical Input Power (dbm) Pmin=0.22dB Pmin=0.11dB Pmin=0.62dB -7.7dB reflection Un-isolation penalty is minimal. 8

9 CWDM DFB Laser Diodes SLT44XX Series Features : nm (8 Colors 2.5Gb/s, LR-2 Applications TFFMUX/DMUX) Wavelength (nm) E620 E855 F095 F340 F590 F850 11nmA 13nmB 2nm 3nm 1490 G G Temperature (deg.c) 9

10 Bi-directional Device (Waveguide( Waveguide-type) TX: RX: LD, Monitor Photodiode Photodiode, Pre-amplifier Back-Facet Monitor PD RX Pre-Amp IC RX PD Laser Diode Straight Waveguide Thin Film Filter ONU OLT Out: 1310nm / 1550nm In: 1550nm / 1310nm Single-Mode Fiber 10

11 Reflection by Bi-directional device 0 Reflection (db) Fiber end LD facet LD facet 1310/1310nm Measured at 1310nm Distance (mm) 1310/1550nm Measured at 1310nm & 1550nm Reflection (db) Fiber end 1550nm 1310nm LD facet LD facet Distance (mm)

12 Bi-directional Transceiver module MicroOptics-type Waveguide-type OR 1310Tx/1550Rx for 2x5 SFF with SC 1550Tx/1310Rx for 2x5 SFF with SC Bi-directional SFF TRx 12

13 Crosstalk measurement at 156Mbps R=0.4A/W LD:ON LD:OFF R=1.0A/W LD:ON LD:OFF 1310/1310nm Back-to to-back 1310/1550nm 10km B.E.R B.E.R dBm dBm Incident Power [dbm] Incident Power [dbm]

14 2-wave 1.25Gbps (b-t-b)( OLT ONU BER R=1.0A/W P f =-10dBm LD:OFF BER R=0.8A/W P f =-10.5dBm LD:OFF dBm BER Received Power (dbm) dBm BER Received Power (dbm)

15 Proposed Link Specifications Item Transmission Speed TX wavelength (range, nm) RMS spectral width (nm) TX output power (average) TX rise/fall time Extinction Ratio (min) RX Sensitivity (range) 1270 ~ 1355 upstream <2nm Specification 1.25Gb/s -3dBm ~ -9dBm <0.26ns 9dB 1480 ~ 1580 downstream <1nm -3dBm ~ -21dBm 15

16 Transmitter Output Characteristics 1.25Gbps Gbps,, PRBS2 23-1, SMF 40 Ta=0 degree C Vcc=3.3V 40 Ta= 70 degree C Vcc=3.3V Output Power (dbm) Output Power (dbm) 16

17 Receiver Sensitivity Characteristics Ta=0 degree C Vcc=3.1 V Sensitivity (dbm) Ta=70 degree C Vcc=3.1V Sensitivity (dbm) Gbps PRBS2 7-1 BER=10-12 Ta=25 degree C Vcc=3.3V Sensitivity (dbm) Ta=0degree C Vcc=3.5V Sensitivity (dbm) Ta=70 degree C Vcc=3.5V Sensitivity (dbm) 17

18 Summary 1310nm FP/1550nm DFB is.. - based on mature WDM technology, - immune to optical reflection, - allowing largest link budget, - utilizing inexpensive uncooled lasers, - implemented with industry-standard Small Form Factor transceiver (SFF TRx), etc., therefore, the most proven, cost-effective and practical P2P Gb/s PMD solution. 18