Ok one other thing you could look at is seeing what your light levels are if the optics you are using supports this. Most modern sfp do support light readings.
Show port 49 (or 50) transceiver info detail... if your optics supports this command you will get transmit and receive power from both sides. It will help determine if you have any layer one issues...
output from a switch
PLW_X430-24t_SS_W38thSt.1 # sh por 25 trans info det
Port : 25
Media Type : LX
Vendor Name : FINISAR CORP.
Part Number : FTRJ1319P1BTL-EX
Serial Number : P8S0NZ0
Wavelength : 1310 nm
Temp (Celsius) : 41.12 Status : Normal
Low Warn Threshold : -30.00 High Warn Threshold : 93.00
Low Alarm Threshold : -40.00 High Alarm Threshold : 110.00
Voltage AUX-1/Vcc (Volts) : 3.31 Status : Normal
Low Warn Threshold : 2.90 High Warn Threshold : 3.70
Low Alarm Threshold : 2.70 High Alarm Threshold : 3.90
Tx Power (dBm) : -4.31 Status : Normal
Low Warn Threshold : -11.51 High Warn Threshold : -1.00
Low Alarm Threshold : -13.51 High Alarm Threshold : 1.00
Rx Power (dBm) : -6.67 Status : Normal
Low Warn Threshold : -20.00 High Warn Threshold : -1.00
Low Alarm Threshold : -23.97 High Alarm Threshold : 0.75
Tx Bias Current (mA): 21.11 Status : Normal
Low Warn Threshold : 4.00 High Warn Threshold : 70.00
Low Alarm Threshold : 2.00 High Alarm Threshold : 80.00